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Lindqvist型多酸衍生物的电子性质的量子化学研究:有机无机杂化的功能材料
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摘要
通过超分子排列方法用各种有机配体设计和合成大量的结构奇特的杂化多金属氧酸盐(POMs)引起了广泛关注,并加快了这类材料的发展。我们使用量子化学方法设计一些更多所谓阴阳离子盐和主客体化合物的杂化材料,这些材料具有活性的电荷磁性质并能够发生解吸附-再吸附过程。多酸可以接受或释放一定数量的电子,并保持结构的完整性,从而充当很好的多电子传播器。这一特性可以使无机有机杂化的多酸化合物活跃在电极修饰和电催化研究中。这些基于多酸的无机有机杂化材料在电学,光学和信息技术领域拥有巨大的发展前景。我们已经对有机无机杂化的功能材料进行了一系列的研究。
     本论文中,采用量子化学方法中的时间依赖的密度泛函方法(TDDFT)对基于多酸的杂化材料的电子性质、偶极极化率、偶极距变化(Δμ)、态密度和二阶非线性光学响应(NLO)进行研究。
     1.第一部分是对功能材料的有价值的补充,在这里,电荷转移方向通过有机配体的链长的改变而改变,六钼酸盐到有机胺的电荷转移是增加这种功能材料的NLO响应的主要决定因素。原为电子受体的多酸簇变成电子供体,而有机胺作为电子受体,它们通过π共轭桥连接实现电子转移,而这种多酸作为电子供体的材料为功能化材料化学开辟了新的领域。本章对一维(D-D-A-A),二维和三维非线性光学材料的理论设计证明有机无机杂化的多酸衍生物具有很大的NLO响应。
     2.第二部分主要报道了二氮烯苯基取代的多酸化合物可调的NLO性质,并且可以提供一种新途径设计并合成基于有机无机杂化多酸衍生物的高效功能材料。含有有机配体的多酸簇改变了体系电荷转移特征,实现了功能材料的新领域。本章采用DFT方法研究二氮烯苯基取代的六钼酸盐的非线性光学性质。二氮烯苯基取代的作为电子供体提高了第一超极化率,NLO性质通过配体的共轭链的增长而增加。因此,可以调节二氮烯苯基取代的六钼酸盐的NLO行为使之成为高效的NLO材料。
     3.六钼酸盐中衍生物有机部分中三联吡啶的引入使之成为超分子化学中有效的分子前驱体。将多酸簇桥联到悬挂的三联吡啶上可以产生供受体化合物并成为潜在的非线性光学材料。本章研究发现改变三联吡啶上的不同取代基可以改变体系的非线性光学响应,并为实验合成新型的功能材料提供合成方案。轨道分析表明多酸和三联吡啶的电荷转移程度在二维的有机金属/多酸杂化体系中增加。这次研究为研究三联吡啶取代的六钼酸盐的大的NLO性质提供了重要的思路。
     4.本章研究发现,有机胺取代的六钼酸盐衍生物的NLO响应可以从218.61×10~(-30) esu增加到490.10×10~(-30) esu。本章采用TDDFT方法研究了有机胺取代的六钼酸盐衍生物的偶极极化率和二阶非线性光学响应。具有吸电子能力的F原子的引入在调节这类有机无机杂化的多酸化合物的NLO响应起到很重要的作用,尤其化合物6[Mo6O18(NC16H8F2(CF3)2I)]2-的静态二阶极化率(βvec)达到490.10×10~(-30) esu。因此我们研究的体系可以成为很好的NLO可控的光学材料。对βvec的主要贡献分析显示沿着z轴从多酸到有机配体的电荷转移由于末端苯环上F原子的加入而提高,并且电荷转移从头部的多酸向末端的氟化的苯环移动。计算的βvec值可以通过在有机胺基团末端的苯环上引入不同的卤素原子进行调节。此外,两个三氟甲基在有机胺末端苯环上I原子两侧的取代极大影响了体系的非线性光学响应,并且使从多酸到有机胺配体的电荷转移随之增加。不同卤素原子的取代给体系的NLO响应的改变带来连锁反应。由于末端基团吸电子能力的增加,体系1到6的NLO响应按照以下顺序增加:CH3 (1) < F (2) < Cl (3) < Br (4) < I (5) < CF3 (6)。因此,我们可以利用这种连锁反应去增大电子受体的能力从而提高对体系NLO响应的影响程度。因此,本章的研究为调节有机胺取代的六钼酸盐的NLO性质提供了有力的研究手段。
     5.三联吡啶取代的六钼酸盐的非线性光学响应可以从体系1的886.55×10~(-30) esu增大到体系7的4622.92×10~(-30) esu。本章采用TDDFT方法对三联吡啶取代的六钼酸盐衍生物的偶极极化率和二阶非线性光学性质进行了研究。量子力学计算发现体系7[Mo_6O_(18)(N_4C_(25)H_(14)(CF_3)_2 (CN)_2)]~(2-)在所有体系中的NLO响应最大。吸电子基团(F, Cl, Br, I, CF3和CN)在三联吡啶末端的引入使电荷转移沿着z轴从多酸簇向三联吡啶转移,从而导致体系7产生更有效的二阶NLO响应。通过取代而造成分子组成上的微小改变却能够导致NLO上极不相称的巨大变化,这种变化称为蝴蝶反应。
     6.本章采用DFT方法研究了钒硅酸盐[Si8V14O50]12-以及相关离子,并对杂原子GeIV, PV, AsV和SiIV的变化对体系的电子和氧化还原性质的影响进行了研究。用GeIV,AsV和PV取代SiIV为实验合成其他的类似钒硅酸盐,钒锗酸盐,钒磷酸盐和钒砷酸盐以及他们的杂多阴离子衍生物提供了一条新途径。
The design and synthesis of novel compounds hybridizing polyoxometalates (POMs) with a variety of organic ligands through supramolecular arrays have aroused particular interest and accelerated the development of this new kind of materials. We have quantum chemically designed these hybrid compounds, which are generally called anion-cation salts and host-guest solids, and which can possess active electrical and magnetic properties as well as desorption-readsorption properties. POMs can accept and release a certain number of electrons without decomposition, thus serving as multielectron relays. This attribute has made these inorganic-organic hybrids very attractive in electrode modification and electrocatalytic research. These POM-based inorganic-organic materials have immense potential in the field of electronics, photonics, and information technology. We have found new and novel insights into the properties of inorganic-organic hybrid functional materials.
     In this thesis, the quantum chemical approach has been carried out to investigate electronic properties, dipole polarizabilities, change of dipole moments (Δμ), density of states, and second-order nonlinear optical (NLO) properties of POM-based inorganic-organic hybrid functional materials by employing time dependent density functional theory (TDDFT).
     1- The first research report is a valuable addition in the field of advanced functional materials where the direction of charge transfer had been altered by changing the length of organic ligand in which hexamolybdates-to-organoimido charge transfer was a vital determinant to increase the NLO response of proposed functional material. The electron accepting property of POM cluster has been changed as it acts as a donor and organoimido ligand acts as an acceptor (D-bridge-A) via charge-transport property ofπ-conjugated bridge which has established the identity of POM as a donor as well in a rigorous way and has opened new horizons in the field of functional material chemistry. Here the quantum design of 1-D (D-D-A-A), 2-D, and 3-D nonlinear optical materials have also been suggested based on inorganic-organic hybrids with remarkably large NLO responses.
     2- In second research report the tunable NLO behavior of aryldiazenido hexamolybdates has been demonstrated and it may provide a new means for experimentalists to design high-performance functional materials based on inorganic-organic hybrid composites. The inclusion of organic ligand in inorganic cluster (POM) has changed the nature and direction of charge transfer which might be a surprising addition in the field of functional materials. The nonlinear optical properties of aryldiazenido hexamolybdates were studied by DFT analysis. An electron donor in the aryldiazenido ligand enhanced the first hyperpolarizability, and the NLO properties could be improved strikingly by increasing the conjugation path of the ligand. Thus, the NLO behavior of aryldiazenido hexamolybdates can be tuned for the design of high-performance NLO materials.
     3- In third research report the inclusion of the terpyridine moiety (organic pendant) in substituted hexamolybdates (POM) is shown to be important because they may act as efficient molecular precursors for application in supramolecular chemistry. The polyoxomolybdate cluster connected to pendant terpyridine units via a bridging group to generate donor-acceptor complexes suitable for applications as non linear optical materials. The study varied the substituents pendant to the terpyridine ligand and the results provide synthetic targets for the development of new functional materials with improved responses through the incorporation of various substituents. The orbital analysis shows that the degree of charge transfer (CT) between POM and terpyridine segment was increased in 2D and organometallic/POM hybrid systems. This investigation provides important and thought provoking insight into the robustly large NLO properties of terpyridine substituted hexamolybdates.
     4- In this work, NLO response of organoimido-substituted hexamolybdates has been tuned from 218.61×10~(-30) esu to 490.10×10~(-30) esu. The dipole polarizabilities and second-order nonlinear optical (NLO) properties of organoimido derivatives of hexamolybdates have been investigated by using time-dependent density functional response theory (TDDFT). The electron with drawing ability of F (fluorine) has played an important role to tune second-order NLO response in this class of organic-inorganic hybrid compounds particularly system 6 [Mo6O18(NC16H8F2(CF3)2I)]2- with the static second-order polarizability (βvec) computed to be 490.10×10~(-30) esu. Thus, our studied systems have feasibility to be excellent tunable second-order nonlinear optical materials. The analysis of the major contributions to theβvec value suggests that the CT from POM to organic ligand (D–A) along the z-axis has been enhanced with addition of F atoms at the end phenyl ring which directs head (POM) to tail (fluorinated ring) charge transfer. The computedβvec values have been tuned by incorporation of different halogen atoms at the end phenyl ring of organoimido segment. Furthermore, substitution of two trifluoromethyl (-CF_3) groups sidewise along with iodine (I) at the terminus of end phenyl ring in organoimido ligand has striking influence to tune the optical nonlinearity as CT from POM to organoimido ligand was significantly increased. The systematic small changes in molecular composition by substitution of different halogen groups cause ripple effect which leads to tuning the NLO response; the so-called“ripple effect”catches this point nicely. The NLO response of systems (1-6) has been increased by increasing the strength of terminal group in the following order: CH_3 (1) < F (2) < Cl (3) < Br (4) < I (5) < CF3 (6). So, we can use the principle of Ripple Effect to magnify the actions of electron acceptors and their effects on NLO responses of studied systems. Thus present investigation provides thought provoking insight into the tunable NLO properties of organoimido substituted hexamolybdates.
     5- A dramatic increase in second-order NLO response of terpyridine-substituted hexamolybdates has been observed from 886.55×10~(-30) esu (system 1) to 4622.92×10~(-30) esu (system 7). The dipole polarizabilities and second-order nonlinear optical (NLO) properties of terpyridine derivatives of hexamolybdates have been investigated by using time-dependent density functional response theory (TDDFT). The Quantum mechanical design suggests that [Mo_6O_(18)(N_4C_(25)H_(14)(CF_3)_2 (CN)_2)]~(2-) (system 7) is the best choice among all studied systems to improve nonlinearity. The electron withdrawing ability of electron acceptor groups (F, Cl, Br, I, CF3 and CN) at the end of terpyridine ligand directs the CT from POM-cluster to terpyridine segment along the z-axis which leads to an efficient second-order NLO molecular designing of our studied systems. These small changes in molecular composition by substitution may have disproportionally huge effects on the NLO properties, the so-called“butterfly effect”catches this point nicely.
     6- In this work, DFT calculations were carried out on vanadosilicate [Si8V14O50]12- and other related anions, the effect of substitution of Ge~(IV), P~V, As~V with Si~(IV) on the electronic and redox properties was investigated. The substitution of Si~(IV) with Ge~(IV), P~V, and As~V may open up possibilities for the experimentalists to synthesize other mimicked vandosilicates, vanadogermenates, vanadophosphates and vanadoarsenates as well as their heteropolyanions respectively.
引文
[1] Pope M T, Müller A. Polyoxometalate Chemistry[M]. Dordrecht: Kluwer, 2001, 1.
    [2] Berzelius J. The preparation of the phophomolybdate ion [PMo12O40]3-[J]. Pogg Ann. 1826, 6: 369-371.
    [3] Keggin J F. Structure of the molecule of 12-phosphotungstic acid[J]. Nature, 1933, 131(3321): 908-909.
    [4] (a) Kozhevnikov I V. Catalysis by heteropoly acids and multicomponent polyoxometalates in liquid-phase reactions[J]. Chem Rev, 1998, 98 (1): 171-198. (b) Mizuno N, Misono M. Heterogenous catalysis[J]. Chem Rev, 1998, 98 (1): 199-218. (c) Sadakane M, Steckhan E. Electrochemical properties of polyoxometalates as electrocatalysts[J] Chem Rev, 1998, 98 (1): 219-238.
    [5] Rhule J T, Hill C L, Judd D A. Polyoxometaltes in medicine[J]. Chem Rev, 1998, 98(1): 327-357.
    [6] (a) Müller A, Peters F, Pope M.T, et al. Polyoxometalates: Very large clusters nanoscale magnets[J]. Chem Rev, 1998, 98: 239-272. (b) Klemperer W G, Wall CG. Polyoxoanion chemistry moves toward the future: From solids and solutions to surfaces[J]. Chem Rev, 1998, 98: 297-306. (c) Pope M T, Müller A. Polyoxometalates: From planotic solids to anti-retroviral activity[M]. Kluwer Academic: Dordrecht, The Netherlands, 1994.
    [7] Wang E B, Hu C W, Xu L, Introduction of Polyoxometalates Chemistry[M]. Bejing: Chemical Industry Press, 1998. 4.
    [8] Clemente-Juan J M, Coronado E. Magnetic clusters from polyoxometalate complexes[J]. Coord Chem Rev, 1999, 193-195: 361-394.
    [9] Lindqvist I. The structure of the hexaniobate anion[J]. Ark Kemi, 1952, 5: 247-250.
    [10] Keggin J F. The structure and formula of 12-phosphotungstic acid [J]. Proc R Soc A, 1934, 144: 75-100.
    [11] Dawson B. The structure of the 9(18)-heteropoly anion in potassium 9(18)-tungstophosphate, K6(P2W18O62)·14H2O[J]. Acta Crystallogr, 1953, 6: 113-126.
    [12] Pope M T. Heteropoly and isopoly oxometalates[M]. Springer-Verlag: Berlin, 1983.
    [13] Hill C L, Guest Editor. Introduction: Polyoxometalates-Multicomponent molecular vehicles to probe fundamental issues and practical problems[J]. Chem Rev, 1998, 98(1): 1-2.
    [14] Katsoulis D E. A survey of applications of polyoxometalates[J]. Chem Rev, 1998, 98(1): 359-387.
    [15] Yamase T. Photo- and electrochromism of polyoxometalates and related materials[J]. Chem Rev, 1998, 98(1): 307-325.
    [16] Coronado E, Gómez-García C J. Polyoxometalate-based molecular materials[J]. Chem Rev, 1998, 98(1): 273-296.
    [17] X-ray structural studies of [Mo6O19]2- with various counteractions include: (a) Allcock H R, Bissell E C, Shaw E T. Crystal and molecular structure of a new hexamolybdate-cyclophosphazene complex[J]. Inorg Chem, 1973, 12(12): 2963-2968. (b) Garner C D, Howlander N C, Mabbs F E, McPhail A T, et al.Studies in eight-coordination part 5: Crystal and molecular structure and electron spin resonance spectra of tetrakis (diethyldithiocarbamato) molybdenum (V) hexamolybdate and chloride[J]. J Chem Soc Dalton Trans, 1978 (11): 1582-1589. (c) Nagano O, Sasaki Y. Acta Cryst, Structure of the hydrated potassium hexamolybdate complex of hexaoxacyclooctadecane (18-crown-6)[J]. 1979, B35: 2387-2389. (d) Clegg W, Sheldrick G M, Garner C D, et al. Structure of bis (tetraphenylarsonium) hexamolybdate(VI)[J]. Acta Crystallogr 1982, B38: 2906-2909. (e) Dahlstrom P, Zubieta J, Neaves B, et al. Bis (tetramethylammonium) hexamolybdate hydrate, [(CH3)4N]2[Mo6O19]·H2O[J]. Cryst Struct Commun, 1982, 11: 463-469. (f) Arzoumanian H, Baldy A, Lai R, et al. Organomet Chem 1985, 295: 343. (g) Shoemaker C B, McAfee L V, Shoemaker D P, et al. Structure of hydronium-1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown 6)-hexamolybdate (VI) (2/2/1)[J]. Acta Crystallogr 1986, C42: 1310-1313. (h) Riera V, Ruiz M A, Villafane F, et al. Organomet Chem, 1988, C4: 345 (i) Zhang C, Ozawa Y, Hayashi Y, et al. Organomet Chem 1989, C21-25: 373. (j) Bernstein S N, Dunbar K R. Novel Strategies for the Synthesis and Crystallization of Electrophilic Dinuclear Cations: Solution and Solid-State Properties of [Re2(NCCH3)10][Mo6O19]2-[J]. Angew Chem Int Ed Engl, 1992, 31(10): 1360-1362.
    [18] Fuchs J, Freiwald W, Hartl H. Determination of the crystal structure of tetrabutylammonium hexaxamolybdate framework[J]. Acta Crystallogr, 1978, B34: 1764-1770.
    [19] Goiffon A, Philippot E, Maurin M. Crystal structure of sodium niobate (Na7) (H3O) Nb6O19.14H2O[J]. Rev Chim Miner, 1980, 17: 466-476.
    [20] Lindqvist I, Aronsson B. The crystal structure of the hexatantalate anion[J]. Ark Kemi 1954, 7: 49-52.
    [21] Although [V6O19]8- is unknown, the hexavanadate core is present in several structurally characterized systems such as the Rh and Ir derivatives [(η5-C5Me5)M]4 [V6O19]: (a) Hayashi Y, Ozawa Y, Isobe K. The first“Vanadate Hexamer”capped by four Pentamethylcyclopentadienyl-rhodium or -iridium groups[J]. Chem Lett, 1989, (18): 425-428. (b) Chae H K, Klemperer W G, Day V W. An organometal hydroxide route to [(C5Me5)Rh]4(V6O19)[J]. Inorg Chem, 1989, 28(8): 1423-1424. (c) Hayashi Y, Ozawa Y, Isobe K. Site-selective oxygen exchange and substitution of organometallic groups in an amphiphilic quadruple-cubane-type cluster. Synthesis and molecular structure of [(MCp*)4V6O19] (M = rhodium, iridium)[J]. Inorg Chem 1991, 30(5): 1025-1033.
    [22] Gouzerh P, Proust A. Main group element, organic, and organometallic derivatives of polyoxometalates[J]. Chem Rev, 1998, 98(1): 77-111.
    [23] Proust A, Villanneau R. In Polyoxometalates from topology via self-assembly to applications[M]. Pope M T, Müller A. Kluwer, Dordrecht. 2001, 23-38.
    [24] Proust A. Functionalized polyoxometalates: A new generation of soluble oxides[J]. Actual Chimique, 2000, (7-8): 55-61.
    [25] Allcock H R, Bissell E C, Shaw E T. Crystal and molecular structure of a new hexamolybdate-cyclophosphazene complex[J]. Inorg Chem, 1973, 12(12): 2963-2968.
    [26] (a) Gouzerh P, Jeannin Y, Proust A, et al. Two novel polyoxomolybdates containing the (MoNO)3- Unit: [Mo5Na(NO)O13(OCH3)4]2- and [Mo6(NO)O18]3-[J]. Angew Chem Int Ed Engl 1989, 28(10): 1363-1364.Angew Chem 1989, 101: 1377-1389. (b) Proust A, Gouzerh P, Robert F. Molybdenum oxo nitrosyl complexes 1. Defect Lindqvist compounds of the type [Mo5O13(OR)4(NO)]3- (R = CH3, C2H5): Solid-state interactions with alkali-metal cations[J]. Inorg Chem, 1993, 32(23): 5291-5298.
    [27] Bank S, Liu S, Shaikh S N, et al. Molybdenum-95 NMR studies of (aryldiazenido)- and (organohydrazido)molybdates. Crystal and molecular structure of [n-Bu4N]3+[Mo6O18(NNC6F5)]3-[J]. Inorg Chem 1988, 27(20): 3535-3543.
    [28] Proust A, Thouvenot R, Herson P. Revisiting the synthesis of [Mo6Cp*O18]-. X-Ray structural analysis, UV-visible, electrochemical and multinuclear NMR characterization[J]. J Chem Soc Dalton Trans 1999, 51-55.
    [29] Kwen H, Young V G, Maatta E A. A diazoalkane derivative of a polyoxometalate: Preparation and structure of [Mo6O18(NNC(C6H4OCH3)CH3)]2-[J]. Angew Chem Int Ed, 1999, 38(8): 1145-1146.
    [30] Du Y, Rheingold A L, Maatta E A. A polyoxometalate incorporating an organoimido ligand: Preparation and structure of [Mo5O18(MoNC6H4CH3)]2-[J]. J Am Chem Soc, 1992, 114(1): 345-346.
    [31] Proust A, Thouvenot R, Chaussade M, et al. Phenylimido derivatives of [Mo6O19]2?: Syntheses, X-ray structures, vibrational, electrochemical, 95Mo and 14N NMR studies[J]. Inorg Chim Acta, 1994, 224(1-2): 81-85.
    [32] Clegg W, Errington R J, Fraser K A, et al. Polyoxometalates: From platonic solids to anti-retroviral activity (Eds.: Pope M T): Kluwer Academic Publishers, Dordrecht, The Netherlands, 1994, 113.
    [33] Strong J B, Yap G P A, Ostrander R, et al. A new class of functionalized polyoxometalates: Synthetic, structural, spectroscopic, and electrochemical studies of organoimido derivatives of [Mo6O19]2-[J]. J Am Chem Soc, 2000, 122(4): 639-649.
    [34] Stark J L, Young V G, Maatta E A, et al. A functionalized polyoxometalate bearing a ferrocenylimido ligand: Preparation and structure of [(FeN)Mo6O18]2-[J]. Angew Chem Int Ed, 1995, 107: 2547-2548.
    [35] Stark J L, Rheingold A L, Maatta E A. Polyoxometalate clusters as building blocks: preparation and structure of bis(hexamolybdate) complexes covalently bridged by organodiimido ligands[J]. J Chem Soc Chem Commun, 1995, 1165-1166.
    [36] Clegg W, Errington R J, Fraser K, et al. Functionalization of [Mo6O19]2- with aromatic-amines: Synthesis and structure of a hexamolybdate building block with linear difunctionality[J]. Chem Commun, 1995, (4): 455-456.
    [37] Wei Y, Xu B, Barnes C L, et al. An efficient and convenient reaction protocol to organoimido derivatives of polyoxometalates[J]. J Am Chem Soc, 2001, 123(17): 4083-4080.
    [38] Roesner R A, McGrath S C, Brockman J T, et al. Mono- and di-functional aromatic amines with p-alkoxy substituents as novel arylimido ligands for the hexamolybdate ion[J]. Inorg Chim Acta, 2003, 342: 37-47.
    [39] Xu L, Lu M, Xu B, et al. Towards main-chain-polyoxometalate-containing hybrid polymers: A highly efficient approach to bifunctionalized organoimido derivatives of hexamolybdates[J]. Angew Chem Int Ed, 2002, 41: 4129-4132.
    [40] Xu B, Wei Y, Peng Z H, et al. Hybrid molecular materials based on covalently linked inorganic polyoxometalates and organic conjugated systems[J]. Angew Chem Int Ed, 2001, 40: 2290-2292.
    [41] Lu M, Wei Y, Xu B, et al. Hybrid molecular dumbbells: Bridging polyoxometalate clusters with an organicπ-conjugated rod[J]. Angew Chem Int Ed, 2002, 41: 1566-1568.
    [42] Xu B B, Peng Z H, Wei Y G, et al. Polyoxometalates covalently bonded with terpyridine ligands[J]. Chem Commun, 2003, 20: 2562-2563.
    [43] Xia Y, Wei Y, Wang Y, et al. A kinetically controlled trans bifunctionalized organoimido derivative of the lindqvist-type hexamolybdate: Synthesis, spectroscopic characterization, and crystal structure of (n-Bu4N)2{trans-[Mo6O17(NAr)2]} (Ar = 2,6-dimethylphenyl)[J]. Inorg Chem, 2005, 44(26): 9823-9828.
    [44] Xia Y, Wu P, Wei Y, et al. Synthesis, crystal structure, and optical properties of a polyoxometalate-based inorganic-organic hybrid solid (n-Bu4N)2[Mo6O17(≡NAr)2] (Ar = o-CH3OC6H4)[J]. Cryst Growth Des, 2006, 6(1): 253-257.
    [45] Yan L K, Su Z M, Guan W, et al. Why does disubstituted hexamolybdate with arylimido prefer to form an orthogonal derivative? Analysis of stability, bonding character, and electronic properties on molybdate derivatives by density functional theory (DFT) study[J]. J Phys Chem B, 2004, 108: 17337-17343.
    [46] Shen Y R. The Principles of nonlinear optics[M]. Wiley: New York, 1984.
    [47] Harper P, Wherrett B. Eds nonlinear optics[M]. Academic Press: New York, 1977.
    [48] Saleh B E A, Teich M C. Fundamentals of photonics[M]. Wiley: New York, 1991.
    [49] Chemla D S, Zyss J. Eds nonlinear optical properties of organic molecules and crystals[M]. Academic Press: Orlando, FL, 1987, 1 and 2:
    [50] Zyss J. Molecular nonlinear optics: Materials, physics and devices[M]. Academic Press: Boston, 1994.
    [51] Bosshard Ch, Sutter K, Prêtre Ph, et al. Organic nonlinear optical materials (Advances in nonlinear optics)[M]. Gordon & Breach: Amsterdam, 1995, 1:
    [52] Nalwa H S, Miyata S. Nonlinear optics of organic molecules and polymers[M]. CRC Press: Boca Raton, FL, 1997, 10: 571-609.
    [53] Nalwa H S. Organometallic materials for nonlinear optics[J]. Appl Organomet Chem, 1991, 5: 349-377.
    [54] Marder S R. Metal-containing materials for nonlinear optics. In inorganic materials[M]. Bruce D W, O’Hare D. Eds Wiley: Chichester, UK, 1992, 2: 121-169.
    [55] Kanis D R, Ratner M A, Marks T J. Design and construction of molecular assemblies with large second-order optical nonlinearities. Quantum chemical aspects[J]. Chem Rev, 1994, 94(1): 195-242.
    [56] Long N. Organometallic compounds for nonlinear optics -The search for enlightenment[J]. Angew Chem Int Ed Engl, 1995, 34: 21-38.
    [57] Whittall I R, McDonagh A M, Humphrey M G, et al. Organometallic complexes in nonlinear optics II: Third-order nonlinearities and optical limiting studies[J]. Adv Organomet Chem 1998, 43: 349-405.
    [58] Whittall I R, McDonagh A M, Humphrey M G, et al. Organometallic complexes in nonlinear optics I: Second-order nonlinearities[J]. Adv Organomet Chem, 1998, 42: 291-362
    [59] Heck J, Dabek S, Meyer-Friedrichsen T, et al. Coord Chem Rev 1999, (190-192): 1217-1254.
    [60] Gray G M, Lawson C M. Structure–property relationships in transition metal-organic third-order nonlinear optical materials. In optoelectronic properties of inorganic compounds[M]. Roundhill D M, Fackler J P, Eds Plenum: New York, 1999, 1-27.
    [61] Shi S. Nonlinear optical properties of inorganic clusters. In optoelectronic properties of inorganic compounds[M]. Roundhill D M, Fackler J P, Jr Eds Plenum: New York, 1999, 55-105 .
    [62] Qin J, Liu D, Dai C, et al. Influence of the molecular configuration on second-order nonlinear optical properties of coordination compounds[J]. Coord Chem Rev 1999, 188: 23-34.
    [63] Barlow S, Marder S R. Electronic and optical properties of conjugated group 8 metallocene derivatives[J]. Chem Commun, 2000, 1555-1562.
    [64] Le Bozec H, Renouard T. Dipolar and non dipolar bipyridine metal complexes for nonlinear optics[J]. Eur J Inorg Chem 2000, 229-239.
    [65] Di Bella S. Second-order nonlinear optical properties of transition metal complexes[J]. Chem Soc Rev, 2001, 30: 355-366.
    [66] Lacroix P G. Second-order optical nonlinearities in coordination chemistry: The case of bis (salicylaldiminato) metal schiff base complexes[J]. Eur J Inorg Chem, 2001, (2): 339-348.
    [67] Zyss J, Ledoux I. Nonlinear optics in multipolar media: theory and experiments[M]. Chem Rev 1994, 94(1): 77-105.
    [68] Tykwinski R. R, Gubler U, Martin R E, et al. Structure-property relationships in third-order nonlinear optical chromophores[J]. J Phys Chem B, 1998, 102: 4451-4465.
    [69] (a) Roundhill D M, Fackler J P. Optoelectronic properties of inorganic compounds[M]. Plenum Press, New York, 1999. (b) Coe B J, in: McCleverty J A, Meyer T J. Eds Comprehensive coordination chemistry[J]. Elsevier Pergamon, Oxford, UK, 2004, 9: 621-687; (c) Coe B J, Curati N R M. Metal complexes for molecular electronics and photonics.[J]. Inorg Chem, 2004, 25: 147-184.
    [70] (a) Oudar J L, Chemla D S. Hyperpolarizabilities of the nitroanilines and their relations to the excited state dipole moment[J]. J Chem Phys, 1977, 66(6): 2664-2668. (b) Oudar J L. Optical nonlinearities of conjugated molecules. Stilbene derivatives and highly polar aromatic compounds[J]. J Chem Phys, 1977, 67(2): 446-457.
    [71] Yan L K, Yang G C, Guan W, et al. Density functional theory study on the first hyperpolarizabilities of organoimido derivatives of hexamolybdates[J]. J phys chem B, 2005, 109: 22332-22336.
    [72] Yan L K, Jin M S, Zhuang J, et al. Theoretical study on the considerable second-order nonlinear optical properties of naphthylimido-substituted hexamolybdates[J]. J Phys Chem A, 2008, 112: 9919-9923.
    [73] Guan W, Yang G C, Yan L K, et al. Prediction of second-order optical nonlinearity of trisorganotin-substitutedβ-Keggin Polyoxotungstate[J]. Inorg Chem 2006, 45: 7864-7868.
    [74] Yang G C, Guan W, Yan L K. Theoretical study on the electronic spectrum and the origin of remarkably large third-order nonlinear optical properties of organoimide derivatives of hexamolybdates[J]. J Phys Chem B, 2006, 110: 23092-23098.
    [75] Janjua M R S A, Liu C G, Guan W, et al. Prediction of remarkably large second-order nonlinear optical properties of organoimido-substituted hexamolybdates[J]. J Phys Chem A, 2009, 113(15): 3576-3587.
    [76] Janjua M R S A, Liu C G, Guan W, et al. A quantum mechanical study of the second-order nonlinear optical properties of aryldiazenido-substituted hexamolybdates: A surprising charge transfer[J]. Eur J Inorg Chem, 2009, 34: 5181-5188.
    [77] Janjua M R S A, Guan W, Yan L K, et al. Prediction of robustly large molecular second-order nonlinear optical properties of terpyridine-substituted hexamolybdates: Structural modelling towards a rational entry to NLO materials[J]. J Mol Graph Model, 2010, DOI:10.1016/j.jmgm.2010.01.011.
    [78] Long D L, Tsunashima R, Cronin L. Polyoxometalates: Building blocks for functional nanoscale systems[J]. Angew Chem Int Ed, 2010, 49: 1736-1758.
    [1] Quantum Chemistry, The NIH Guide to Molecular Modeling. National Institutes of Health. Retrieved 2007-09-08.
    [2] Planck M. On the law of distribution of energy in the normal spectrum". Annalen der Physik, 1901, 4: 553.
    [3] Young D. C. Computational chemistry: A practical guide for applying techniques to real-world problems[M]. New York: John Wiley & Sons, Inc, 2001.7-92.
    [4] Ventura O. N. and Kieninger M. Computational chemistry as an analytical tool: Thermochemical examples in atmospheric chemistry[J]. Pure & Appl Chem, 1998, 70 (12): 2301- 2307.
    [5] Lewars E. Computational chemistry introduction to the theory and applications of molecular and quantum mechanics[M]. New York: Kluwer Academic Publishers, 2004, 1-6.
    [6] HyperChem manual, Computational chemistry, practical guide, theory and methods[M]. Canada: Hypercube, Inc, 1996, 7-10.
    [7] Cramer C. J. Essential of computational chemistry theories and models, second edition[M]. Chichester, England: John Wiley & Sons Ltd, 2004,1-16.
    [8] Foresman J B, Frisch E. Exploring chemistry with electronic structure methods, second edition[M]. Pittsburgh: Gaussian, Inc, 1996, 165-183.
    [9] Schr?dinger E. An introductory theory of the mechanics of atoms and molecules[J]. Phys Rev, 1926, 28(6): 1049-1070.
    [10] Grosse H, Martin A. Particle physics and Schr?dinger equation[M]. Cambridge: Cambridge University press.
    [11] (a) Jensen F. Introduction to computational chemistry[M]. Chichester, England: John Wiley & Sons Ltd, 1999, XIII-5: 53-284 (b) Zheng X. A computational investigation of hydrocarbon cracking: Gas phase and heterogeneous catalytic reactions on zeolites[D]: PhD thesis, Arizona: University of Arizona, 2005.
    [12] Lewars E. Computational chemistry: Introduction to the theory and applications of molecular and quantum mechanics[M]. New York: Kluwer Academic Publishers, 2004, 1-78.
    [13] Mueller M. Fundamentals of quantum chemistry molecular spectroscopy and modern electronic structure computations[M]. New York: Kluwer Academic Publishers, 2002, 14-33.
    [14] Tsai C. S. An introduction to computational biochemistry[M]. New York: Wiley-Liss, 2002, 291-339.
    [15] Schubert E F. Physical foundations of solid-state devices[M]. New York: Rensselaer Polytechnic Institute, Troy, 2005, 27-32.
    [16] (a) Born M, Oppenheimer J R. Zur quantentheorie der molekeln[J]. Ann Physik, 1927, 84(20): 457-484. (b) Born M, Huang K. Dynamical theory of crystal lattices[M]. New York: Oxford UniversityPress, 1954.
    [17] Rogers D W. Computational chemistry using the PC[M]. New Jersey: John Wiley & Sons, 2003, 93-108.
    [18] Koch W, Holthausen M C. A chemist’s guide to density functional theory[M]. Weinheim, Germany: Wiley-VCH Verlag, 2001, 8-71.
    [19] Maseras F, Lledós A. Computational modeling of homogenous catalysis[M]. New York: Kluwer Academic Publishers, 2002, 13-18.
    [20] Parr R G, Yang W. Density functional theory of atoms and molecules[M]. Oxford: Oxford University Press, Inc, 1989, 1-75.
    [21] Atkins P W, Friedman R S. Molecular quantum mechanics third edition[M]. Oxford: 1996, 276-290.
    [22] Eschrig H. The fundamentals of density functional theory[M]. Germany: B. G. Teubner Verlagsgesellschaft, Leipzig, 1996, 23-29.
    [23] Dreizler R M, Gross E U. Density functional theory: An approach to the quantum many-body problem[M]. Berlin: Springer-Verlag, 1990, 7-162.
    [24] Leach A R. Molecular modelling principles and applications[M]. Harlow, England: Pearson Education Limited, 2001.
    [25] Geerlings P, De Proft F, Langenaeker W. Conceptual density functional theory[J]. Chem Rev, 2003, 103: 1793-1878.
    [26] Ziegler T. Approximate density functional theory as a practical tool in molecular energetics and dynamics[J]. Chem Rev, 1991, 91: 651-667.
    [27] Parr R G, Yang W. Density-functional theory of the electronic structure of molecules[J]. Annu Rev Phys Chem, 1995, 46: 701-728.
    [28] Koch W, Holthausen M C. A chemist’s guide to density functional theory, Wiley-VCH, Weinheim: Germany, 2000.
    [29] Hohenberg P, Kohn W. Inhomogeneous electron gas[J]. Phys Rev B, 1964, 136: 864-871.
    [30] Kohn W, Sham L J. Self-consistent equations including exchange and correlation effects[J]. Phys Rev, 1965, 140 (4A): 1133-1138.
    [1] Pope M T. Heteropoly and isopoly oxometalates[M]. New York: Springer-Verlag, 1983, 1.
    [2] Hill C L, Guest Editor. Introduction: Polyoxometalates-Multicomponent molecular vehicles to probe fundamental issues and practical problems[J]. Chem Rev, 1998, 98(1): 1-2.
    [3] Pope M L. Müller A. Polyoxometalate chemistry: An old field with new dimensions in several disciplines[J]. Angew Chem Int Ed Engl, 1991, 30(1): 34-48.
    [4] Hill C L, Prosser-McCarther C M. Homogenous catalysis by transition metal oxygen anion clusters[J]. Coord Chem Rev, 1995, 143: 407-455.
    [5] Baker L C W, Figgis J S. New fundamental type of inorganic complex: Hybrid between heteropoly and conventional coordination complexes. Possibilities for geometrical isomerisms in 11-, 12-, 17-, and 18-heteropoly derivatives[J]. J Am Chem Soc, 1970, 92(12): 3794-3797.
    [6] Zeng H, Newkome G R, Hill C T. Poly(polyoxometalate) dendrimers: Molecular prototypes of new catalytic materials[J]. Angew Chem Int Ed, 2000, 39(10): 1771-1774.
    [7] Gouzerh P, Proust A. Main group element, organic, and organometallic derivatives of polyoxometalates[J]. Chem Rev, 1998, 98(1): 77-111.
    [8] Du Y, Rheingold A L, Maatta E A. A polyoxometalate incorporating an organoimido ligand: Preparation and structure of [Mo5O18(MoNC6H4CH3)]2-[J]. J Am Chem Soc, 1992, 114(1): 345-346.
    [9] Clegg W, Errington R J, Fraser K, et al. Functionalization of [Mo6O19]2- with aromatic-amines: Synthesis and structure of a hexamolybdate building block with linear difunctionality[J]. Chem Commun, 1995, (4): 455-456.
    [10] Proust A, Thouvenot R, Chaussade M, et al. Phenylimido derivatives of [Mo6O19]2-: Syntheses, X-ray structures, vibrational, electrochemical, 95Mo and 14N NMR studies[J]. Inorg Chim Acta, 1994, 224(1-2): 81-95.
    [11] Wei Y G, Xu B B, Barnes C L, et al. An efficient and convenient reaction protocol to organoimido derivatives of polyoxometalates[J]. J Am Chem Soc 2001, 123(17): 4083-4084.
    [12] Wei Y G, Lu M, Cheung C F, et al. Functionalization of [MoW5O19]2- with aromatic amines: Synthesis of the first arylimido derivatives of mixed-metal polyoxometalates[J]. Inorg Chem, 2001, 40(22): 5489-5490.
    [13] Xu L, Lu M, Xu B B, et al. Towards main-chain-polyoxometalate containing hybrid polymers: A highly efficient approach to bifunctionalized organoimido derivatives of hexamolybdates[J]. Angew Chem Int Ed, 2002, 41(21): 4129-4132.
    [14] Judeinstein P. Synthesis and properties of polyoxometalates based inorganic-organic polymers[J]. Chem Mater, 1992, 4(1): 4-7.
    [15] Strong J B, Yap G P A, Ostrander R, et al. A new class of functionalized polyoxometalates: Synthetic, structural, spectroscopic, and electrochemical studies of organoimido derivatives of [Mo6O19]2-[J]. J Am Chem Soc, 2000, 122(4): 639-649.
    [16] (a) Mayer C R, Cabuil V, Lalot T, et al. Incorporation of magnetic nanoparticles into new hybrid networks on the basis of Heteropolyanions and polyacrylamide[J]. Angew Chem, 1999, 111(24): 3878-3881. (b) Mayer C R, Cabuil V, Lalot T, et al. Incorporation of magnetic nanoparticles in new hybrid networks based on heteropolyanions and polyacrylamide[J]. Angew Chem Int Ed, 1999, 38(24): 3672-3675.
    [17] Mayer C R, Thouvenot R, Lalot T. New hybrid covalent networks based on polyoxometalates: Part 1. hybrid networks based on poly(ethyl methacrylate) chains covalently cross-linked by heteropolyanions: Synthesis and swelling properties[J]. Chem Mater, 2000, 12(2): 257-260.
    [18] Schroden R C, Blanford C F, Melde B J, et al. Direct synthesis of ordered macroporous silica materials functionalized with polyoxometalate clusters[J]. Chem Mater, 2001, 13(3): 1074-1081.
    [19] Johnson B J S, Stein A. Surface modification of mesoporous, macroporous, and amorphous silica with catalytically active polyoxometalate clusters[J]. Inorg Chem, 2001, 40(4): 801-808.
    [20] Strong J B, Haggerty B S, Rheingold A L, et al. A superoctahedral complex derived from a polyoxometalate:the hexakis (arylimido) hexamolybdate anion [Mo6(NAr)6O13H]2-[J]. Chem Commun, 1997, 1137-1138.
    [21] Moore A R, Kwen H, Beatty A B, et al. Organoimido-polyoxometalates as polymer pendants[J]. Chem Commun, 2000, 1793-1794.
    [22] Xu B B, Wei Y G, Barnes C L, et al. Hybrid molecular materials based on covalently linked inorganic polyoxometalates and organic conjugated systems[J]. Angew Chem Int Ed 2001, 40(12): 2290-2292.
    [23] Lu M, Wei Y G, Xu B B, et al. Hybrid molecular dumbbells: Bridging polyoxometalate clusters with an organic pi-conjugated rod[J]. Angew Chem Int Ed, 2002, 41(9): 1566-1568.
    [24] (a) Pope M T. Heteropoly and isopoly oxometalates[M]. Springer-Verlag: Berlin, 1983. (b) Pope M T, Müller A. Polyoxometalates: From platonic solid to anti-retroviral activity[M]. Kluwer: Dordrecht, 1994. (c) Rhule J T, Hill C L, Judd D A. Polyoxometaltes in medicine[J]. Chem Rev, 1998, 98(1): 327-357. (d) Hasenknopf B. Polyoxometalates: Introduction to a class of inorganic compounds and their biomedical applications[J]. Front Biosci, 2005, 10: 275-287. (e) Yin C X, Sasaki Y, Finke R G. Auto-oxidation-Product-Initiated dioxygenases: Vanadium-based, record catalytic lifetime catechol dioxygenase catalysis[J]. Inorg Chem, 2005, 44(23): 8521-8530. (f) Gong Y, Hu C W, Liang H. Research progress in synthesis and catalysis of polyoxometalates[J]. Prog Nat Sci, 2005, 15(5): 385-394. (g) Proust A. Functionalized polyoxometalates: A new generation of soluble oxides[J]. Actual Chimique, 2000, (7-8): 55-61. (h) Casa?-Pastor N, Gomez-Romero P. Polyoxometalates: From inorganic chemistry to materials science[J]. Front Biosci, 2004, 9: 1759-1770.
    [25] Gouzerh P, Proust A. Main-group element, organic, and organometallic derivatives of polyoxometalates[J]. Chem Rev, 1998, 98(1): 77-111.
    [26] Coronado E, Gómez-García C J. Polyoxometalate-based molecular materials[J]. Chem Rev, 1998, 98(1): 273-296.
    [27] Blau W. Organic materials for nonlinear optical devices[J]. Phys Technol, 1987, 18(6): 250-257.
    [28] Nie W. Optical nonlinearity: Phenomena, applications, and materials[J]. Adv Mater, 1993, 5(7-8): 520-545.
    [29] Powell C E, Humphrey M G. Nonlinear optical properties of transition metal acetylides and their derivatives[J]. Coord Chem Rev, 2004, 248(7-8): 725-756.
    [30] Bredas J L, Adant C, Tackx P, et al. Third-order nonlinear optical response in organic materials: Theoretical and experimental aspects[J]. Chem Rev, 1994, 94(1): 243-278.
    [31] Katsoulis D E. A survey of applications of polyoxometalates[J]. Chem Rev, 1998, 98(1): 359-387.
    [32] Yan L K, Su Z M, Guan W, et al. Why does disubstituted hexamolybdate with arylimido prefer to form an orthogonal derivative? Analysis of stability, bonding character, and electronic properties on molybdate derivatives by density functional theory (DFT) study[J]. J Phys Chem B, 2004, 108: 17337-17343.
    [33] Yan L K, Yang G C, Guang W, et al. Density functional theory study on the first hyperpolarizabilities of organoimido derivatives of hexamolybdates[J]. J Phys Chem B, 2005, 109: 22332-22336.
    [34] Bredas J L, Beljonne D, Coropceanu V, et al. Charge-Transfer and energy-transfer processes in pi.-conjugated oligomers and polymers: A molecular picture[J]. Chem Rev, 2004, 104(11): 4971-5003.
    [35] Locknar S A, Peteanu L A, Shuai Z G. Calculation of ground and excited state polarizabilities of unsubstituted and donor/acceptor polyenes: A comparison of the finite-field and sum-over-states methods[J]. J Phys Chem A, 1999, 103(14): 2197-2201.
    [36] van Gisbergen S J A, Snijders J G, Baerends E J. Accurate density functional calculations on frequency-dependent hyperpolarizabilities of small molecules[J]. J Chem Phys, 1998, 109(24): 10657-10668.
    [37] (a) Rohmer M M, Bénard M, Blaudeau J P, et al. From Lindqvist and Keggin ions to electronically inverse hosts: AB initio modelling of the structure and reactivity of polyoxometalates[J]. Coord Chem Rev, 1998, 178-180: 1019-1049. (b) Lopez X, Bo C, Poblet J M. Electron and proton affinity of mixed-addenda Keggin and Wells-Dawson anions[J]. J Am Chem Soc, 2002, 124(42): 12574-12582. (c) Bridgeman A J, Cavigliasso G. Electronic structure of theαandβisomers of [Mo8O26]4-[J]. Inorg Chem, 2002, 41(13): 3500-3507.
    [38] Yang G C, Guang W, Yan L K, et al. Theoretical study on the electronic spectrum and the origin of remarkably large third-order nonlinear optical properties of organoimide derivatives of hexamolybdates[J]. J Phys Chem B, 2006, 110: 23092-23098.
    [39] (a) te Velde G, Bickelhaupt F M, Baerends E J, et al. Chemistry with ADF[J]. J Comput Chem, 2001, 22(9): 931-967. (b) Guerra C F, Snijders J G, Te Velde G, et al. Towards an order-N DFT method[J]. Theor Chem Acc 1998, 99(6): 391-403. (c) ADF2006.01, SCM, Theoretical Chemistry, Vrije Universiteit, Amsterdam, The Netherlands, http://www.scm.com
    [40] van Lenthe E, Baerends E J, Snijders J G. Relativistic regular two-component Hamiltonians[J]. J Chem Phys, 1993, 99(9): 4597-4610
    [41] Becke A D. Density-functional exchange-energy approximation with correct asymptotic behavior[J]. Phys Rev A, 1988, 38(6): 3098-3100.
    [42] Perdew J P. Density-functional approximation for the correlation energy of the inhomogeneous electron gas[J]. Phys Rev B, 1986, 33(12): 8822-8824.
    [43] van Gisbergen S J A, Snijders J G, Baerends E J. Implementation of time-dependent density functional response equations[J]. Comp Phys Commun, 1999, 118(2-3): 119-138.
    [44] van Leeuwen R, Baerends E J. Exchange-correlation potential with correct asymptotic behavior[J]. Phys Rev A, 1994, 49(4): 2421-2431.
    [45] van Gisbergen S J A, Osinga V P, Gritsenko O V, et al. Improved density functional theory results for frequency-dependent polarizabilities, by the use of an exchange-correlation potential with correct asymptotic behavior[J]. J Chem Phys, 1996, 105(8): 3142-3151.
    [46] van Gisbergen S J A, Snijders J G, Baerends E J. Time-dependent density functional results for the dynamic hyperpolarizability of C60[J]. Phys Rev Lett, 1997, 78(16): 3097-3100.
    [47] van Gisbergen S J A, Snijders J G, Baerends E J J. Calculating frequency-dependent hyperpolarizabilities using time-dependent density functional theory[J]. Chem Phys, 1998, 109(24): 10644-10656.
    [48] Grozema F C, Telesca R, Jonkman H T, et al. Excited state polarizabilities of conjugated molecules calculated using time dependent density functional theory[J]. J Chem Phys, 2001, 115(21): 10014-10021.
    [49] O'Boyle N M, Tenderholt A L, Langner K M. A library for package-independent computational chemistry algorithms[J]. J Comp.Chem, 2008, 29: 839-845.
    [50] (a) Guan W, Yang G C, Yan L K, et al. Prediction of second-order optical nonlinearity of trisorganotin-substitutedβ-keggin polyoxotungstate[J]. Inorg Chem, 2006, 45(19): 7864-7868. (b) Guan W, Yang G C, Yan L K, et al. How do the different defect structures and element substitutions affect the nonlinear optical properties of lacunary keggin polyoxometalates? A DFT study[J]. Eur J Inorg Chem, 2006, (20): 4179-4183.
    [51] Carey D M L, Munoz-Castro A, Bustos C J, Manriquez J M, et al.π-Donor/Acceptor effect on Lindqvist type polyoxomolibdates because of various multiple-bonded nitrogenous ligands[J]. J. Phys. Chem. A. 2007, 111(28): 6563-6567.
    [52] (a) Lu M, Wei Y G, Xu B B, et al. Hybrid molecular dumbbells: Bridging polyoxometalate clusters with an organic pi-conjugated rod[J]. Angew Chem Int Ed, 2002, 41(9): 1566-1568. (b) Xu B B, Wei Y G, Barnes C L, et al. Hybrid molecular materials based on covalently linked inorganic polyoxometalates and organic conjugated systems[J]. Angew Chem Int Ed, 2001, 40(12) : 2290-2292.
    [53] Yan L K, Jin M S, Zhuang J, et al. Theoretical study on the considerable second-order nonlinear optical properties of naphthylimido-substituted hexamolybdates[J]. J Phys Chem A, 2008, 112: 9919-9923.
    [54] Kanis D R, Ratner M A, Marks T J. Design and construction of molecular assemblies with large second-order optical nonlinearities. Quantum chemical aspects[J]. Chem Rev, 1994, 94(1): 195-242.
    [55] Pal S K, Krishnan A, Das P K, et al. Schiff base linked ferrocenyl complexes for second-order nonlinear optics[J]. J Organomet Chem, 2000, 604(2): 248-259.
    [56] (a) Oudar J L, Chemla D S. Hyperpolarizabilities of the nitroanilines and their relations to the excited state dipole moment[J]. J Chem Phys, 1977, 66(6): 2664-2668. (b) Oudar J L. Optical nonlinearities of conjugated molecules. Stilbene derivatives and highly polar aromatic compounds[J]. J Chem Phys, 1977, 67(2): 446-457.
    [57] Haberlen O D, Chung S C, Stener M, et al. From clusters to bulk: A relativistic density functional investigation on a series of gold clusters Aun, n = 6,…,147[J]. J Chem Phys 1997, 106(12): 5189-5201.
    [58] Xia Y, Wu P, Wei Y, et al. Synthesis, Crystal Structure, and Optical Properties of a Polyoxometalate-Based Inorganic-Organic Hybrid Solid, (n-Bu4N)2[Mo6O17(≡NAr)2] (Ar = o-CH3OC6H4)[J]. Cryst Growth Des, 2006, 6(1): 253-257.
    [59] Stark J L, Young V G, Maatta E A, et al. A functionalized polyoxometalate bearing a ferrocenylimido ligand: Preparation and structure of [(FeN)Mo6O18]2-[J]. Angew Chem Int Ed, 1995, 107: 2547-2548.
    [60] Rao V P, Jen A K Y, Chandrasekhar J, et al. The important role of heteroaromatics in the design of efficient second-order nonlinear optical molecules: Theoretical investigation on push-pull heteroaromatic stilbenes[J]. J Am Chem Soc, 1996, 118 (49): 12443-12448.
    [61] Cheng L, Tam W, Stevenson S H, et al. Experimental investigations of organic molecular nonlinear optical polarizabilities. 1. Methods and results on benzene and stilbene derivatives[J]. J Phys Chem, 1991, 95(26): 10631-10643.
    [1] Pope M T, Heteropoly and isopoly oxometalates[M]. New York: Springer Verlag, 1983, 1.
    [2] Pope M T, Müller A. Polyoxometalate Chemistry: An old field with new dimensions in several disciplines[M]. Angew Chem Int Ed Engl, 1991, 30(1): 34-48.
    [3] Pope M T, Müller A. Polyoxometalates: From planotic solids to anti-retroviral activity[M]. Kluwer Academic: Dordrecht, The Netherlands, 1994.
    [4] Pope M T. In Comprehensive Coordination Chemistry II: From biology to nanotechnology[M]. Wedd AG Ed Elsevier Ltd, Oxford, U.K 2004 4: 635-678.
    [5] Hill C L. In Comprehensive Coordination Chemistry-II: From biology to nanotechnology[M]. Wedd AG Ed Elsevier: Oxford 2004, 4: 679-759.
    [6] Hill C L, Guest Editor. Introduction: Polyoxometalates-Multicomponent molecular vehicles to probe fundamental issues and practical problems[J]. Chem Rev, 1998, 98(1): 1-2.
    [7] (a) Sanchez C, Soler-Illia D, Ribot F, et al. Designed hybrid organic?inorganic nanocomposites from functional nanobuilding blocks[J]. Chem Mater, 2001, 13(10): 3061-3083. (b) Xu L, Lu M, Xu B B, et al. Towards main-chain-polyoxometalate containing hybrid polymers: A highly efficient approach to bifunctionalized organoimido derivatives of hexamolybdates[J]. Angew Chem Int Ed, 2002, 41(21): 4129-4132. (c) Lu M, Wei Y G, Xu B B, et al. Hybrid molecular dumbbells: Bridging polyoxometalate clusters with an organic pi-conjugated rod[J]. Angew Chem Int Ed, 2002, 41(9): 1566-1568. (d) Xu B B, Wei Y G, Barnes C L, et al. Hybrid molecular materials based on covalently linked inorganic polyoxometalates and organic conjugated systems[J]. Angew Chem Int Ed, 2001, 40(12) : 2290-2292.
    [8] (a) Dolbecq A, Mialane P, Lisnard L, et al. Hybrid organic-inorganic 1D and 2D frameworks with -Keggin polyoxomolybdates as building blocks[J]. Chem Eur J, 2003, 9(12): 2914-2920. (b) Kang J, Xu B, Peng Z, et al. Molecular and polymeric hybrids based on covalently linked polyoxometalates and transition-metal complexes[J]. Angew Chem Int Ed, 2005, 44: 6902-6905.(c) Xu B, Peng Z, Wei Y, et al. Polyoxometalates covalently bonded with terpyridine ligands[J]. Chem Commun, 2003, 20: 2562-2563.
    [9] (a) Sadakane M, Dickman M H, Pope M T. Controlled Assembly of Polyoxometalate Chains from Lacunary Building Blocks and Lanthanide-Cation Linkers[J]. Angew Chem Int Ed, 2000, 39(16): 2914-2916. (b) Li Q, Wei Y, Hao J, et al. Unexpected C:C bond formation via doubly dehydrogenative coupling of two saturated sp3 C-H bonds activated with a polymolybdate[J]. J Am Chem Soc, 2007, 129(18): 5810–5811. (c) Zhu Y, Wang L, Hao J, et al. Synthetic, structural, spectroscopic, electrochemical studies and self-assembly of nanoscale polyoxometalate?organic hybrid molecular dumbbells[J]. Cryst Growth Des, 2009, 9(8): 3509–3518.
    [10] Kortz U, Savelieff M G, Abou Ghali F Y, et al. Heteropolymolybdates of AsIII, SbIII, BiIII, SeIV, and TeIV functionalized by amino acids[J]. Angew Chem Int Ed, 2002, 41(21): 4070-4072.
    [11] (a) Yuan M, Li Y G, Wang E B, et al. Hydrothermal synthesis and crystal structure of a hybrid material based on [Co4(phen)8(H2O)2(HPO3)2]4+ and a highly reduced polyoxoanion[J]. J Chem Soc Dalton Trans,2002, 2916-2920. (b) Li Y G, Hao N, Wang E B, et al. New high-dimensional networks based on polyoxometalate and crown ether building blocks[J]. Inorg Chem 2003, 42(8): 2729-2735.
    [12] Eaton D F. Nonlinear optical materials[J]. Science, 1991, 253(5017): 281-287.
    [13] Marder S R, Cheng L T, Tiemann B G, et al. Large first hyperpolarizabilities in push-pull polyenes by tuning of the bond length alternation and aromaticity[J]. Science, 1994, 263(5146): 511-514.
    [14] Blanchard-Desce M, Alain V, Bedworth P V, et al. Large quadratic hyperpolarizabilities with donor-acceptor polyenes exhibiting optimum bond length alternation: Correlation between structure and hyperpolarizability[J]. Chem Eur J, 1997, 3(7): 1091-1104.
    [15] Cheng W D, Xiang K H, Pandey R, et al. Calculations of linear and nonlinear optical properties of H-Silsesquioxanes[J]. J Phys Chem B, 2000, 104(29): 6737-6742.
    [16] Ichida M, Sohda T, Nakamura A. Third-order nonlinear optical properties of C60 CT complexes with aromatic amines[J]. J Phys Chem B, 2000, 104(30): 7082-7084.
    [17] Powell C E, Humphrey M G. Nonlinear optical properties of transition metal acetylides and their derivatives[J]. Chem Rev, 2004, 248(7-8): 725-756.
    [18] Guan W, Yang G C, Yan L K, et al. Prediction of second-order optical nonlinearity of trisorganotin-substitutedβ-keggin polyoxotungstate[J]. Inorg Chem, 2006, 45(19): 7864-7868.
    [19] Rohmer M M, Bénard M, Blaudeau J P, et al. From Lindqvist and Keggin ions to electronically inverse hosts: AB initio modelling of the structure and reactivity of polyoxometalates[J]. Coord Chem Rev, 1998, 178-180: 1019-1049.
    [20] Lopez X, Bo C, Poblet J M. Electron and proton affinity of mixed-addenda Keggin and Wells-Dawson anions[J]. J Am Chem Soc, 2002, 124(42): 12574-12582.
    [21] Bridgeman A J, Cavigliasso G. Electronic structure of theαandβisomers of [Mo8O26]4-[J]. Inorg Chem, 2002, 41(13): 3500-3507.
    [22] Fernandez J A, Lopez X, Bo C, et al. Polyoxometalates with internal cavities: Redox activity, basicity, and cation encapsulation in [Xn+P5W30O110](15-n)- Preyssler complexes, with X = Na+, Ca2+, Y3+, La3+, Ce3+, and Th4+[J]. J Am Chem Soc, 2007, 129(40): 12244-12253.
    [23] Romo S, Fernandez J A, Maestre J M, et al. Density Functional Theory and ab Initio Study of Electronic and Electrochemistry Properties of the Tetranuclear Sandwich Complex [FeIII4(H2O)2(PW9O34)2]6-[J]. Inorg Chem, 2007, 46(10): 4022-4027.
    [24] Yan L K, Su Z M, Guan W, et al. Why does disubstituted hexamolybdate with arylimido prefer to form an orthogonal derivative? Analysis of stability, bonding character, and electronic properties on molybdate derivatives by density functional theory (DFT) study[J]. J Phys Chem B, 2004, 108: 17337-17343.
    [25] Guan W, Yan L K, Su Z M, et al. Electronic properties and stability of dititaniumIV substitutedα-Keggin polyoxotungstate with heteroatom phosphorus by DFT[J]. Inorg Chem, 2005, 44(1): 100-107.
    [26] Yan L K, Su Z M, Tan K, et al. Electronic properties of Strandberg anions: A DFT study of [X2Mo5O23]n-, (X = PV, SVI, AsV, SeVI), and [(RP)2Mo5O21]4- (R = H, CH3, C2H5)[J]. Int J Quantum Chem, 2005, 105(1): 37-42.
    [27] Guan W, Yan L K, Su Z M, et al. Density functional study of protonation sites ofα-Keggin isopolyanions[J]. Int J Quantum Chem, 2006, 106(8): 1860-1864.
    [28] X-ray structural studies of [Mo6O19]2- with various counteractions include: (a) Allcock H R, Bissell E C, Shaw E T. Crystal and molecular structure of a new hexamolybdate-cyclophosphazene complex[J]. Inorg Chem, 1973, 12(12): 2963-2968. (b) Garner C D, Howlander N C, Mabbs F E, McPhail A T, et al. Studies in eight-coordination part 5: Crystal and molecular structure and electron spin resonance spectra oftetrakis (diethyldithiocarbamato) molybdenum (V) hexamolybdate and chloride[J]. J Chem Soc Dalton Trans, 1978 (11): 1582-1589. (c) Nagano O, Sasaki Y. Acta Cryst, Structure of the hydrated potassium hexamolybdate complex of hexaoxacyclooctadecane (18-crown-6)[J]. 1979, B35: 2387-2389. (d) Clegg W, Sheldrick G M, Garner C D, et al. Structure of bis (tetraphenylarsonium) hexamolybdate(VI)[J]. Acta Crystallogr 1982, B38: 2906-2909. (e) Dahlstrom P, Zubieta J, Neaves B, et al. Bis (tetramethylammonium) hexamolybdate hydrate, [(CH3)4N]2[Mo6O19]·H2O[J]. Cryst Struct Commun, 1982, 11: 463-469. (f) Arzoumanian H, Baldy A, Lai R, et al. Organomet Chem 1985, 295: 343. (g) Shoemaker C B, McAfee L V, Shoemaker D P, et al. Structure of hydronium-1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown 6)-hexamolybdate (VI) (2/2/1)[J]. Acta Crystallogr 1986, C42: 1310-1313. (h) Riera V, Ruiz M A, Villafane F, et al. Organomet Chem, 1988, C4: 345 (i) Zhang C, Ozawa Y, Hayashi Y, et al. Organomet Chem 1989, C21-25: 373. (j) Bernstein S N, Dunbar K R. Novel Strategies for the Synthesis and Crystallization of Electrophilic Dinuclear Cations: Solution and Solid-State Properties of [Re2(NCCH3)10][Mo6O19]2-[J]. Angew Chem Int Ed Engl, 1992, 31(10): 1360-1362.
    [29] Fuchs J, Freiwald W, Hartl H. Determination of the crystal structure of tetrabutylammonium hexaxamolybdate framework[J]. Acta Crystallogr, 1978, B34: 1764-1770.
    [30] (a) Lindqvist I. The structure of the hexaniobate anion[J]. Ark Kemi, 1952, 5: 247-250. (b) Goiffon A, Philippot E, Maurin M. Crystal structure of sodium niobate (Na7) (H3O) Nb6O19.14H2O[J]. Rev Chim Miner, 1980, 17: 466-476.
    [31] Lindqvist I, Aronsson B. The crystal structure of the hexatantalate anion[J]. Ark Kemi 1954, 7: 49-52
    [32] Although [V6O19]8- is unknown, the hexavanadate core is present in several structurally characterized systems such as the Rh and Ir derivatives [(η5-C5Me5)M]4 [V6O19]: (a) Hayashi Y, Ozawa Y, Isobe K. The first“Vanadate Hexamer”capped by four Pentamethylcyclopentadienyl-rhodium or -iridium groups[J]. Chem Lett, 1989, (18): 425-428. (b) Chae H K, Klemperer W G, Day V W. An organometal hydroxide route to [(C5Me5)Rh]4(V6O19)[J]. Inorg Chem, 1989, 28(8): 1423-1424. (c) Hayashi Y, Ozawa Y, Isobe K. Site-selective oxygen exchange and substitution of organometallic groups in an amphiphilic quadruple-cubane-type cluster. Synthesis and molecular structure of [(MCp*)4V6O19] (M = rhodium, iridium)[J]. Inorg Chem 1991, 30(5): 1025-1033.
    [33] Gouzerh P, Proust A. Main group element, organic, and organometallic derivatives of polyoxometalates[J]. Chem Rev, 1998, 98(1): 77-111.
    [34] Proust A, Villanneau R. In Polyoxometalates from topology via self-assembly to applications[M]. Pope M T, Müller A. Kluwer, Dordrecht. 2001, 23-38.
    [35] (a) Gouzerh P, Jeannin Y, Proust A, et al. Two novel polyoxomolybdates containing the (MoNO)3- Unit: [Mo5Na(NO)O13(OCH3)4]2- and [Mo6(NO)O18]3-[J]. Angew Chem Int Ed Engl 1989, 28(10): 1363-1364. Angew Chem 1989, 101: 1377-1389. (b) Proust A, Gouzerh P, Robert F. Molybdenum oxo nitrosyl complexes 1. Defect Lindqvist compounds of the type [Mo5O13(OR)4(NO)]3- (R = CH3, C2H5): Solid-state interactions with alkali-metal cations[J]. Inorg Chem, 1993, 32(23): 5291-5298. (c) Proust A, Thouvenot R, Robert F, et al. Molybdenum oxo nitrosyl complexes. 2. Molybdenum-95 NMR studies of defect and complete Lindqvist-type derivatives. Crystal and molecular structure of (n-Bu4N)2[Mo6O17(OCH3)(NO)][J]. Inorg Chem, 1993, 32(23): 5299-5304. (d) Proust A, Thouvenot R, Roh S G, et al. Lindqvist-type oxo-nitrosyl complexes: Syntheses, vibrational, multinuclear magnetic resonance (14N, 17O, 95Mo, and 183W), and electrochemical studies of [M5O18{M'(NO)}]3- anions (M, M' = Mo, W)[J]. Inorg Chem, 1995, 34(16): 4106-4112. (e) Proust A, Fournier M, Thouvenot R, et al. Synthesis and characterization of Keggin derivatives containing an [Mo(NO)]3+ unit: (n-Bu4N)4[PM11O39{Mo(NO)}] (M = Mo, W)[J]. Inorg Chim Acta, 1994, 215(1-2): 61-66.
    [36] Proust A, Thouvenot R, Chaussade M, et al. Phenylimido derivatives of [Mo6O19]2-: Syntheses, X-ray structures, vibrational, electrochemical, 95Mo and 14N NMR studies[J]. Inorg Chim Acta, 1994, 224(1-2): 81-95.
    [37] Strong J B, Yap G P A, Ostrander R, et al. A new class of functionalized polyoxometalates: Synthetic, structural, spectroscopic, and electrochemical studies of organoimido derivatives of [Mo6O19]2-[J]. J Am Chem Soc, 2000, 122(4): 639-649.
    [38] Kwen H, Tomlinson S, Maatta E A, et al. Functionalized heteropolyanions: high-valent metal nitrido fragments incorporated into a Keggin polyoxometalate structure[J]. Chem Commun, 2002, 24: 2970-2971.
    [39] Bustos C, Hasenknopf B, Thouvenot R, et al. Lindqvist-type (aryldiazenido) polyoxomolybdates: Synthesis, and structural and spectroscopic characterization of compounds of the type (nBu4N)3 [Mo6O18(N2Ar)]3-[J]. Eur J Inorg Chem, 2003, (15): 2757-2766.
    [40] (a) te Velde G, Bickelhaupt F M, Baerends E J, et al. Chemistry with ADF[J]. J Comput Chem, 2001, 22(9): 931-967. (b) Guerra C F, Snijders J G, Te Velde G, et al. Towards an order-N DFT method[J]. Theor Chem Acc 1998, 99(6): 391-403. (c) ADF2006.01, SCM, Theoretical Chemistry, Vrije Universiteit, Amsterdam, The Netherlands, http://www.scm.com
    [41] van Lenthe E, Baerends E J, Snijders J G. Relativistic regular two-component Hamiltonians[J]. J Chem Phys, 1993, 99(9): 4597-4610
    [42] Becke A D. Density-functional exchange-energy approximation with correct asymptotic behavior[J]. Phys Rev A, 1988, 38(6): 3098-3100.
    [43] Perdew J P. Density-functional approximation for the correlation energy of the inhomogeneous electron gas[J]. Phys Rev B, 1986, 33(12): 8822-8824.
    [44] van Gisbergen S J A, Snijders J G, Baerends E J. Implementation of time-dependent density functional response equations[J]. Comp Phys Commun, 1999, 118(2-3): 119-138.
    [45] van Leeuwen R, Baerends E J. Exchange-correlation potential with correct asymptotic behavior[J]. Phys Rev A, 1994, 49(4): 2421-2431.
    [46] van Gisbergen S J A, Snijders J G, Baerends E J J. Calculating frequency-dependent hyperpolarizabilities using time-dependent density functional theory[J]. Chem Phys, 1998, 109(24): 10644-10656.
    [47] van Gisbergen S J A, Osinga V P, Gritsenko O V, et al. Improved density functional theory results for frequency-dependent polarizabilities, by the use of an exchange-correlation potential with correct asymptotic behavior[J]. J Chem Phys, 1996, 105(8): 3142-3151.
    [48] van Gisbergen S J A, Snijders J G, Baerends E J. Time-dependent density functional results for the dynamic hyperpolarizability of C60[J]. Phys Rev Lett, 1997, 78(16): 3097-3100.
    [49] van Gisbergen S J A, Snijders J G, Baerends E J. Accurate density functional calculations on frequency-dependent hyperpolarizabilities of small molecules[J]. J. Chem Phys, 1998, 109(24): 10657-10668.
    [50] O'Boyle N M, Tenderholt A L, Langner K M. A library for package-independent computational chemistry algorithms[J]. J Comp.Chem, 2008, 29: 839-845.
    [51] Janjua M R S A, Liu C G, Guan W, et al. Prediction of remarkably large second-order nonlinear optical properties of organoimido-substituted hexamolybdates[J]. J Phys Chem A, 2009, 113(15): 3576-3587. (b) Si Y L, Liu C G, Wang E B, et al. Theoretical study on the two-dimensional second-order nonlinear optical properties: A series of charge transfer covalently bonded organoimido derived hexamolybdates complexes[J]. Theor Chem Account, 2009, 122: 217-226.
    [52] (a) Yan L K, Yang G C, Guang W, et al. Density functional theory study on the first hyperpolarizabilities of organoimido derivatives of hexamolybdates[J]. J Phys Chem B, 2005, 109: 22332-22336. (b) Yan L K, Jin M S, Zhuang J, et al. Theoretical study on the considerable second-order nonlinear optical properties of naphthylimido-substituted hexamolybdates[J]. J Phys Chem A, 2008, 112: 9919-9923.
    [53] (a) Zhuang J, Yan L K, Liu C.G, et al. A quantum chemical study of the structure, bonding characteristics and nonlinear optical properties of aryloxido and salicylaldehydo derivatives of [XW5O18]3- (X = Zr or Ti)[J]. Eur J Inorg Chem, 2009, 31: 2529-2535. (b) Yang G C, Guang W, Yan L K, et al. Theoretical study on the electronic spectrum and the origin of remarkably large third-order nonlinear optical properties of organoimide derivatives of hexamolybdates[J]. J Phys Chem B, 2006, 110: 23092-23098. (c) Yan L K, Su Z M, Guan W, et al. Why does disubstituted hexamolybdate with arylimido prefer to form an orthogonal derivative? Analysis of stability, bonding character, and electronic properties on molybdate derivatives by density functional theory (DFT) study[J]. J Phys Chem B, 2004, 108: 17337-17343.
    [54] (a) Guan W, Yang G C, Yan L K, et al. Prediction of second-order optical nonlinearity of trisorganotin-substitutedβ-keggin polyoxotungstate[J]. Inorg Chem, 2006, 45(19): 7864-7868. (b) Guan W, Yang G C, Yan L K, et al. How do the different defect structures and element substitutions affect the nonlinear optical properties of lacunary keggin polyoxometalates? A DFT study[J]. Eur J Inorg Chem, 2006, (20): 4179-4183. [55] Mac-Leod Carey D, Mu?oz-Castro A, Bustos C J, et al.π-Donor/Acceptor effect on lindqvist type polyoxomolibdates because of various multiple-bonded nitrogenous ligands[J]. J Phys Chem A, 2007, 111: 6563-6567.
    [56] Kanis D R, Ratner M A, Marks T J. Design and construction of molecular assemblies with large second-order optical nonlinearities. Quantum chemical aspects[J]. Chem Rev, 1994, 94(1): 195-242.
    [57] Pal S K, Krishnan A, Das P K, et al. Schiff base linked ferrocenyl complexes for second-order nonlinear optics[J]. J Organomet Chem, 2000, 604(2): 248-259.
    [58] (a) Oudar J L, Chemla D S. Hyperpolarizabilities of the nitroanilines and their relations to the excited state dipole moment[J]. J Chem Phys, 1977, 66(6): 2664-2668. (b) Oudar J L. Optical nonlinearities of conjugated molecules. Stilbene derivatives and highly polar aromatic compounds[J]. J Chem Phys, 1977, 67(2): 446-457.
    [59] Kanis D R, Ratner M A, Marks T J. Calculation and electronic description of quadratic hyperpolarizabilities Toward a molecular understanding of NLO responses in organotransition metal chromophores[J]. J Am Chem Soc, 1992, 114(26): 10338-10357.
    [1] Pope M T, Heteropoly and isopoly oxometalates[M]. New York: Springer Verlag, 1983, 1.
    [2] Pope M T, Müller A. Polyoxometalate Chemistry: An old field with new dimensions in several disciplines[M]. Angew Chem Int Ed Engl, 1991, 30(1): 34-48.
    [3] Pope M T, Müller A. Polyoxometalates: From planotic solids to anti-retroviral activity[M]. Kluwer Academic: Dordrecht, The Netherlands, 1994.
    [4] Hill C L, Guest Editor. Introduction: Polyoxometalates-Multicomponent molecular vehicles to probe fundamental issues and practical problems[J]. Chem Rev, 1998, 98(1): 1-2.
    [5] Nalwa H S. Handbook of organic conductive molecules and polymers Ed Wiley, Chichester, 1997, I–IV: 487-515.
    [6] Bredas J L, Silbey R. Conjugated polymers[M]. Kluwer Academic: Dordrecht, The Netherlands, 1991, 315-362.
    [7] Kraft A, Grimsdale A C, Holmes A B. Electroluminescent conjugated polymers - seeing polymers in a new light[J]. Angew Chem Int Ed, 1998, 37: 402-428.
    [8] Pope M, Swenberg C E. Electronic processes in organic crystals and polymers, 2nd ed., Oxford University Press, Oxford, 1999, 482-494.
    [9] Stark J L, Young V G, Maatta E A. A functionalized polyoxometalate bearing a ferrocenylimido ligand: Preparation and structure of [(FcN)Mo6O18]2-[J]. Angew Chem Int Ed, 1995, 34: 2547-2548.
    [10] Stark J L, Rheingold A L, Maatta E A. Polyoxometalate clusters as building blocks: Preparation and structure of bis(hexamolybdate) complexes covalently bridged by organodi-imido ligands[J]. J Chem Soc Chem Commun, 1995, 11: 1165-1166.
    [11] Blau W. Nonlinear optical effects in organic polymers[J]. Phys Technol, 1987, 18: 250-268.
    [12] Nalwa H S, Miyata S. Nonlinear optics of organic molecules and polymers[M]. CRC Press: Boca Raton, FL, 1997, 10: 571-609.
    [13] Zyss J. Molecular nonlinear optics: Materials, physics and devices[M]. Academic Press: Boston, 1994.
    [14] Chemla D S, Zyss J. Nonlinear optical properties of organic molecules and crystals[M]. Academic Press: Orlando, FL, 1987, Vols. 1 and 2.
    [15] Powell C E, Humphrey M G. Nonlinear optical properties of transition metal acetylides and their derivatives[J]. Chem Rev, 2004, 248(7-8): 725-756.
    [16] Le Bozec H, Renouard T. Dipolar and non dipolar bipyridine metal complexes for nonlinear optics[J]. Eur J Inorg Chem 2000, 229-239.
    [17] Qin J, Liu D, Dai C, et al. Influence of the molecular configuration on second-order nonlinear optical properties of coordination compounds[J]. Coord Chem Rev 1999, 188: 23-34.
    [18] Whittall I R, McDonagh A M, Humphrey M G, et al. Organometallic complexes in nonlinear optics I: Second-order nonlinearities[J]. Adv Organomet Chem, 1998, 42: 291-362.
    [19] Long N. Organometallic compounds for nonlinear optics -The search for enlightenment[J]. Angew Chem Int Ed Engl, 1995, 34: 21-38. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Eur J Inorg Chem, 2009, 2529-2535 www.eurjic.org
    [20] Heck J, Dabek S, Meyer-Friedrichsen T, et al. Mono- and dinuclear sesquifulvalene complexes, organometallic materials with large nonlinear optical properties[J]. Coord Chem Rev, 1999, 190: 1217-1254.
    [21] Barlow S, Marder S R. Electronic and optical properties of conjugated group 8 metallocene derivatives[J]. Chem Commun, 2000, 1555-1562.
    [22] Nalwa H S. Organometallic materials for nonlinear optics[J]. Appl Organomet Chem, 1991, 5: 349-377.
    [23] Di Bella S. Second-order nonlinear optical properties of transition metal complexes[J]. Chem Soc Rev, 2001, 30: 355-366.
    [24] Yan L K, Yang G C, Guang W, et al. Density functional theory study on the first hyperpolarizabilities of organoimido derivatives of hexamolybdates[J]. J Phys Chem B, 2005, 109: 22332-22336.
    [25] Yan L K, Jin M S, Zhuang J, et al. Theoretical study on the considerable second-order nonlinear optical properties of naphthylimido-substituted hexamolybdates[J]. J Phys Chem A, 2008, 112: 9919-9923.
    [26] (a) Yang G C, Guang W, Yan L K, et al. Theoretical study on the electronic spectrum and the origin of remarkably large third-order nonlinear optical properties of organoimide derivatives of hexamolybdates[J]. J Phys Chem B, 2006, 110: 23092-23098. (b) Guan W, Yang G C, Yan L K, et al. Prediction of second-order optical nonlinearity of trisorganotin-substitutedβ-keggin polyoxotungstate[J]. Inorg Chem, 2006, 45(19): 7864-7868. (c) Yan L K, Su Z M, Guan W, et al. Why does disubstituted hexamolybdate with arylimido prefer to form an orthogonal derivative? Analysis of stability, bonding character, and electronic properties on molybdate derivatives by density functional theory (DFT) study[J]. J Phys Chem B, 2004, 108: 17337-17343.
    [27] Janjua M R S A, Liu C G, Guan W, et al. Prediction of remarkably large second-order nonlinear optical properties of organoimido-substituted hexamolybdates[J]. J Phys Chem A, 2009, 113(15): 3576-3587.
    [28] Xu B, Peng Z, Wei Y, et al. Polyoxometalates covalently bonded with terpyridine ligands[J]. Chem Commun, 2003, 20: 2562-2563.
    [29] (a) te Velde G, Bickelhaupt F M, Baerends E J, et al. Chemistry with ADF[J]. J Comput Chem, 2001, 22(9): 931-967. (b) Guerra C F, Snijders J G, te Velde G, et al. Towards an order-N DFT method[J]. Theor Chem Acc, 1998, 99(6): 391-403. (c) ADF2008.01, SCM, Theoretical Chemistry, Vrije Universiteit, Amsterdam, The Netherlands, http://www.scm.com
    [30] van Lenthe E, Baerends E J, Snijders J G. Relativistic regular two-component Hamiltonians[J]. J Chem Phys, 1993, 99(9): 4597-4610.
    [31] Becke A D. Density-functional exchange-energy approximation with correct asymptotic behavior[J].Phys Rev A, 1988, 38(6): 3098-3100.
    [32] Perdew J P. Density-functional approximation for the correlation energy of the inhomogeneous electron gas[J]. Phys Rev B, 1986, 33(12): 8822-8824.
    [33] van Gisbergen S J A, Snijders J G, Baerends E J. Implementation of time-dependent density functional response equations[J]. Comp Phys Commun, 1999, 118(2-3): 119-138.
    [34] van Leeuwen R, Baerends E J. Exchange-correlation potential with correct asymptotic behavior[J]. Phys Rev A, 1994, 49(4): 2421-2431.
    [35] (a) van Gisbergen S J A, Osinga V P, Gritsenko O V, et al. Implementation of time-dependent density functional response equations[J]. J Chem Phys, 1996, 105(7): 3142-3151. (b) van Gisbergen S J A, Snijders J G, Baerends E J J. Calculating frequency-dependent hyperpolarizabilities using time-dependent density functional theory[J]. Chem Phys, 1998, 109(24): 10644-10656.
    [36] van Gisbergen S J A, Snijders J G, Baerends E J J. Time-dependent density functional results for the dynamic hyperpolarizability of C60[J]. Chem Phys Rev lett, 1997, 78: 3097-3100.
    [37] van Gisbergen S J A, Snijders J G, Baerends E J. Accurate density functional calculations on frequency-dependent hyperpolarizabilities of small molecules[J]. J. Chem Phys, 1998, 109(24): 10657-10668.
    [38] O'Boyle N M, Tenderholt A L, Langner K M. A library for package-independent computational chemistry algorithms[J]. J Comp.Chem, 2008, 29: 839-845.
    [39] (a) Zhuang J, Yan L K, Liu C.G, et al. A quantum chemical study of the structure, bonding characteristics and nonlinear optical properties of aryloxido and salicylaldehydo derivatives of [XW5O18]3- (X = Zr or Ti)[J]. Eur J Inorg Chem, 2009, 31: 2529-2535. (b) Janjua M R S A, Liu C G, Guan W, et al. A quantum mechanical study of the second-order nonlinear optical properties of aryldiazenido-substituted hexamolybdates: A surprising charge transfer[J]. Eur J Inorg Chem, 2009, 34: 5181-5188. (c) Si Y L, Liu C G, Wang E B, et al. Theoretical study on the two-dimensional second-order nonlinear optical properties: A series of charge transfer covalently bonded organoimido derived hexamolybdates complexes[J]. Theor Chem Account, 2009, 122: 217-226. (d) Yan L K, Dou Z, Guan W, et al. A DFT study on the electronic and redox properties of [PW11O39(ReN)]n– (n =3,4,5)and [PW11O39(OsN)]2–[J]. Eur J Inorg Chem, 2006, 5126-5129. (e) Guan W, Yang G C, Yan L K, et al. How do the different defect structures and element substitutions affect the nonlinear optical properties of lacunary keggin polyoxometalates? A DFT study[J]. Eur J Inorg Chem, 2006, (20): 4179-4183.
    [40] (a) Oudar J L, Chemla D S. Hyperpolarizabilities of the nitroanilines and their relations to the excited state dipole moment[J]. J Chem Phys, 1977, 66(6): 2664-2668. (b) Oudar J L. Optical nonlinearities of conjugated molecules. Stilbene derivatives and highly polar aromatic compounds[J]. J Chem Phys, 1977, 67(2): 446-457.
    [41] Kang J, Xu B, Peng Z, et al. Molecular and polymeric hybrids based on covalently linked polyoxometalates and transition-metal complexes[J]. Angew Chem Int Ed, 2005, 44: 6902-6905.
    [42] Mac-Leod Carey D, Mu?oz-Castro A, Bustos C J, et al.π-Donor/Acceptor effect on lindqvist typepolyoxomolibdates because of various multiple-bonded nitrogenous ligands[J]. J Phys Chem A, 2007, 111: 6563-6567.
    
    [1] Baker L C W, Glick D C. Present general status of understanding of heteropoly electrolytes and a tracing of some major highlights in the history of their elucidation[J]. Chem Rev, 1998, 98(1): 3-49.
    [2] Pope M T, Heteropoly and isopoly oxometalates[M]. Springer: Berlin 1983, 35, 101.
    [3] Jeannin Y P. The nomenclature of polyoxometalates: How to connect a name and a structure[J]. Chem Rev, 1998, 98(1): 51-76.
    [4] Pope M L. Müller A. Polyoxometalate chemistry: An old field with new dimensions in several disciplines[J]. Angew Chem Int Ed Engl, 1991, 30(1): 34-48.
    [5] Coronado E, Gómez-García C J. Polyoxometalate-based molecular materials[J]. Chem Rev, 1998, 98(1): 273-296.
    [6] Katsoulis D E. A survey of applications of polyoxometalates[J]. Chem Rev, 1998, 98(1): 359-387.
    [7] Weinstock I A. Homogeneous-phase electron-transfer reactions of polyoxometalates[J]. Chem Rev 1998, 98(1): 113-170.
    [8] Sadakane M, Steckhan E. Electrochemical properties of polyoxometalates as electrocatalysts[J]. Chem Rev, 1998, 98: 219-238.
    [9] Kozhevnikov I V. Catalysis by heteropoly acids and multicomponent polyoxometalates in liquid-phase reactions[J]. Chem Rev, 1998, 98 (1): 171-198.
    [10] Müller A, Peters F, Pope M.T, et al. Polyoxometalates: Very large clusters nanoscale magnets[J]. Chem Rev, 1998, 98: 239-272.
    [11] Hasenknopf B. Polyoxometalates: Introduction to a class of inorganic compounds and their biomedical applications[J]. Front Biosci, 2005, 10: 275-287.
    [12] Rhule J T, Hill C L, Judd D A. Polyoxometaltes in medicine[J]. Chem Rev, 1998, 98(1): 327-357.
    [13] Mizuno N, Misono M. Heterogenous catalysis[J]. Chem Rev, 1998, 98(1): 199-218.
    [14] Gouzerh P, Proust A. Main group element, organic, and organometallic derivatives of polyoxometalates[J]. Chem Rev, 1998, 98(1): 77-111.
    [15] Blau W. Organic materials for nonlinear optical devices[J]. Phys Technol, 1987, 18(6): 250-257.
    [16] Nalwa H S, Miyata S. Nonlinear optics of organic molecules and polymers[M]. CRC Press: Boca Raton, FL, 1997, 10: 571-609.
    [17] Zyss J. Molecular nonlinear optics: Materials, physics and devices[M]. Academic Press: Boston, 1994.
    [18] Chemla D S, Zyss J. Nonlinear optical properties of organic molecules and crystals[M]. Academic Press: Orlando, FL, 1987, Vols. 1 and 2.
    [19] Powell C E, Humphrey M G. Nonlinear optical properties of transition metal acetylides and their derivatives[J]. Chem Rev, 2004, 248(7-8): 725-756.
    [20] Le Bozec H, Renouard T. Dipolar and non dipolar bipyridine metal complexes for nonlinear optics[J]. Eur J Inorg Chem 2000, 229-239.
    [21] Qin J, Liu D, Dai C, et al. Influence of the molecular configuration on second-order nonlinear optical properties of coordination compounds[J]. Coord Chem Rev 1999, 188: 23-34.
    [22] Whittall I R, McDonagh A M, Humphrey M G, et al. Organometallic complexes in nonlinear optics I: Second-order nonlinearities[J]. Adv Organomet Chem, 1998, 42: 291-362.
    [23] Long N. Organometallic compounds for nonlinear optics -The search for enlightenment[J]. Angew Chem Int Ed Engl, 1995, 34: 21-38. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Eur J Inorg Chem, 2009, 2529-2535 www.eurjic.org
    [24] Heck J, Dabek S, Meyer-Friedrichsen T, et al. Mono- and dinuclear sesquifulvalene complexes, organometallic materials with large nonlinear optical properties[J]. Coord Chem Rev, 1999, 190: 1217-1254.
    [25] Barlow S, Marder S R. Electronic and optical properties of conjugated group 8 metallocene derivatives[J]. Chem Commun, 2000, 1555-1562.
    [26] Nalwa H S. Organometallic materials for nonlinear optics[J]. Appl Organomet Chem, 1991, 5: 349-377.
    [27] Di Bella S. Second-order nonlinear optical properties of transition metal complexes[J]. Chem Soc Rev, 2001, 30: 355-366.
    [28] Yan L K, Yang G C, Guang W, et al. Density functional theory study on the first hyperpolarizabilities of organoimido derivatives of hexamolybdates[J]. J Phys Chem B, 2005, 109: 22332-22336.
    [29] (a) Yan L K, Jin M S, Zhuang J, et al. Theoretical study on the considerable second-order nonlinear optical properties of naphthylimido-substituted hexamolybdates[J]. J Phys Chem A, 2008, 112: 9919-9923. (b) Janjua M R S A, Liu C G, Guan W, et al. Prediction of remarkably large second-order nonlinear optical properties of organoimido-substituted hexamolybdates[J]. J Phys Chem A, 2009, 113(15): 3576-3587.
    [30] Guan W, Yang G C, Yan L K, et al. Prediction of second-order optical nonlinearity of trisorganotin-substitutedβ-keggin polyoxotungstate[J]. Inorg Chem, 2006, 45: 7864-7868.
    [31] (a) Yang G C, Guang W, Yan L K, et al. Theoretical study on the electronic spectrum and the origin of remarkably large third-order nonlinear optical properties of organoimide derivatives of hexamolybdates[J]. J Phys Chem B, 2006, 110: 23092-23098. (b) Yan L K, Su Z M, Guan W, et al. Why does disubstituted hexamolybdate with arylimido prefer to form an orthogonal derivative? Analysis of stability, bonding character, and electronic properties on molybdate derivatives by density functional theory (DFT) study[J]. J Phys Chem B, 2004, 108: 17337-17343.
    [32] (a) te Velde G, Bickelhaupt F M, Baerends E J, et al. Chemistry with ADF[J]. J Comput Chem, 2001, 22(9): 931-967. (b) Guerra C F, Snijders J G, te Velde G, et al. Towards an order-N DFT method[J]. Theor Chem Acc, 1998, 99(6): 391-403. (c) ADF2008.01, SCM, Theoretical Chemistry, Vrije Universiteit, Amsterdam, The Netherlands, http://www.scm.com
    [33] (a) van Lenthe E, Baerends E J, Snijders J G. Relativistic regular two-component hamiltonians[J]. J Chem Phys, 1993, 99(9): 4597-4610. (b) Vosko S H, Wilk L, Nusair M. Accurate spin-dependent electron liquid correlation energies for local spin-density calculations: A critical analysis[J]. Can J Phys, 1980, 58(8): 1200-1211.
    [34] Becke A D. Density-functional exchange-energy approximation with correct asymptotic behavior[J]. Phys Rev A, 1988, 38: 3098-3100.
    [35] Perdew J P. Density-functional approximation for the correlation energy of the inhomogeneous electron gas[J]. Phys Rev B, 1986, 33: 8822-8824.
    [36] van Gisbergen S J A, Snijders J G, Baerends E J. Implementation of time-dependent density functional response equations[J]. Comp Phys Commun, 1999, 118(2-3): 119-138.
    [37] van Leeuwen R, Baerends E J. Exchange-correlation potential with correct asymptotic behavior[J]. Phys Rev A, 1994, 49(4): 2421-2431.
    [38] van Gisbergen S J A, Osinga V P, Gritsenko O V, et al. Improved density functional theory results for frequency-dependent polarizabilities, by the use of an exchange-correlation potential with correct asymptotic behavior[J]. J Chem Phys, 1996, 105(8): 3142-3151.
    [39] (a) van Gisbergen S J A, Snijders J G, Baerends E J J. Time-dependent density functional results for the dynamic hyperpolarizability of C60[J]. Chem Phys Rev Lett, 1997, 78: 3097-3100. (b) van Gisbergen S J A, Snijders J G, Baerends E J J. Calculating frequency-dependent hyperpolarizabilities using time-dependent density functional theory[J]. Chem Phys, 1998, 109(24): 10644-10656.
    [40] van Gisbergen S J A, Snijders J G, Baerends E J J. Accurate density functional calculations on frequency-dependent hyperpolarizabilities of small molecules[J]. Chem Phys, 1998, 109: 10657-10668.
    [41] (a) Yan L K, Yang G C, Guang W, et al. Density functional theory study on the first hyperpolarizabilities of organoimido derivatives of hexamolybdates[J]. J Phys Chem B, 2005, 109: 22332-22336. (b) Si Y L, Liu C G, Wang E B, et al. Theoretical study on the two-dimensional second-order nonlinear optical properties: A series of charge transfer covalently bonded organoimido derived hexamolybdates complexes[J]. Theor Chem Account, 2009, 122: 217-226. (c) Janjua M R S A, Liu C G, Guan W, et al. A quantum mechanical study of the second-order nonlinear optical properties of aryldiazenido-substituted hexamolybdates: A surprising charge transfer[J]. Eur J Inorg Chem, 2009, 34: 5181-5188.
    [42] (a) Zhuang J, Yan L K, Liu C.G, et al. A quantum chemical study of the structure, bonding characteristics and nonlinear optical properties of aryloxido and salicylaldehydo derivatives of [XW5O18]3- (X = Zr or Ti)[J]. Eur J Inorg Chem, 2009, 31: 2529-2535. (b) Guan W, Yang G C, Yan L K, et al. Prediction of second-order optical nonlinearity of trisorganotin-substitutedβ-keggin polyoxotungstate[J]. Inorg Chem, 2006, 45: 7864-7868. (c) Yan L K, Jin M S, Zhuang J, et al. Theoretical study on the considerable second-order nonlinear optical properties of naphthylimido-substituted hexamolybdates[J]. J Phys Chem A, 2008, 112: 9919-9923.
    [43] (a) Papagni A, Maiorana S, Del Buttero P, et al. Synthesis and spectroscopic and NLO properties of “Push-Pull”structures incorporating the inductive electron-withdrawing pentafluorophenyl group[J]. Eur J Org Chem, 2002, (8): 1380-1384. (b) Romaniello P, Lelj F. Effects of fluorine atoms on the optical nonlinear response of stilbene derivatives[J]. J Fluorine Chem, 2004, 125(2): 145-149. (c) Cariati E, Forni A, Biella S, et al. Tuning second-order NLO responses through halogen bonding[J]. Chem Commun, 2007, 2590-2592. (d) Proust A, Villanneau R. In Polyoxometalates from topology via self-assembly to applications[M]. Pope M T, Müller A. Kluwer, Dordrecht. 2001, 23-38. (e) Peng Z H. Rational synthesis of covalently bonded organic?inorganic hybrids[J]. Angew Chem Int Ed, 2004, 43: 930-935. (e) Zhu L, Zhu Y, Meng X, et al. DCC-Assisted esterification of a polyoxometalate-functionalized phenol with carboxylic acids (DCC: dicyclohexylcarbodiimide)[J]. Chem-Eur J, 2008, 14(35): 10923-10927. (f) Wu P, Li Q, Ge N, et al. An easy route to monofunctionalized organoimido derivatives of the Lindqvist hexamolybdate[J]. Eur J Inorg Chem, 2004, (14) 2819-2822. (g) Wei Y G, Xu B B, Barnes C L, et al. An efficient and convenient reaction protocol to organoimido derivatives of polyoxometalates[J]. J Am Chem Soc 2001, 123(17): 4083-4084. (h) Xue S, Chai A, Wei Y, et al. Two novel mono-organoimido functionalized polyoxometalate clusters: Convenient synthesis, crystal structure and bioactivity of [(n-C4H9)4N]2[Mo6O18(NAr)] (Ar = o-CF3C6H4, p-OCF3C6H4)[J]. J Mol St, 2008, 888(1-3): 300-306. (i) Li Q, Wei Y, Guo H, et al. Syntheses, structural characterizations and electronic absorption spectra simulation of three phenylimido substituted hexamolybdates incorporating a remote chloro group[J]. Inorg Chim Acta, 2008, 361(8): 2305-2313. (j) Li Q, Zhu L, Meng X, et al. Two new bromo-functionalized organoimido derivatives of hexamolybdate: Synthesis, crystal structure, spectroscopic and electrochemical studies[J]. Inorg Chim Acta, 2007, 360(8): 2558-2564. (k) Kwen H, Beatty A M, Maatta E A. C R Chimie, 2005, 8: 1025-1028.
    [44] (a) Xu B B, Wei Y G, Barnes C L, et al. Hybrid molecular materials based on covalently linked inorganic polyoxometalates and organic conjugated systems[J]. Angew Chem Int Ed, 2001, 40(12): 2290-2292. (b) Lu M, Wei Y G, Xu B B, et al. Hybrid molecular dumbbells: Bridging polyoxometalate clusters with an organic pi-conjugated rod[J]. Angew Chem Int Ed, 2002, 41(9): 1566-1568.
    [45] (a) Oudar J L, Chemla D S. Hyperpolarizabilities of the nitroanilines and their relations to the excited state dipole moment[J]. J Chem Phys, 1977, 66(6): 2664-2668. (b) Oudar J L. Optical nonlinearities of conjugated molecules. Stilbene derivatives and highly polar aromatic compounds[J]. J Chem Phys, 1977, 67(2): 446-457.
    [1] Pope M L. Müller A. Polyoxometalate chemistry: An old field with new dimensions in several disciplines[J]. Angew Chem Int Ed Engl, 1991, 30(1): 34-48
    [2] An extensive and authoritative treatise on polyoxometalate chemistry is: Pope M T. Heteropoly and isopoly oxometalates[M]. Springer- Verlag: New York, 1983, 35: 101-117.
    [3] Hill C L, Guest Editor. Introduction: Polyoxometalates-Multicomponent molecular vehicles to probe fundamental issues and practical problems[J]. Chem Rev, 1998, 98(1): 1-2.
    [4] A recent monograph highlighting many aspects of current polyoxometalate research is: Polyoxometalates: From platonic solids to anti-retroviral activity[M]. Pope M T, Muller A, Eds Kluwer Academic Publishers: Dordrecht, The Netherlands, 1994, 1-411. Pope M T, Müller A. Polyoxometalates: From planotic solids to anti-retroviral activity[M]. Kluwer Academic: Dordrecht, The Netherlands, 1994.
    [5] Gouzerh P, Proust A. Main group element, organic, and organometallic derivatives of polyoxometalates[J]. Chem Rev, 1998, 98(1): 77-111.
    [6] Lacroix P G. Second-order optical nonlinearities in coordination chemistry: The case of bis (salicylaldiminato) metal schiff base complexes[J]. Eur J Inorg Chem, 2001, (2): 339-348.
    [7] Di Bella S. Second-order nonlinear optical properties of transition metal complexes[J]. Chem Soc Rev, 2001, 30: 355-366.
    [8] Kanis D R, Ratner M A, Marks T J. Design and construction of molecular assemblies with large second-order optical nonlinearities. Quantum chemical aspects[J]. Chem Rev, 1994, 94(1): 195-242 [9] Zyss J, Ledoux I. Chem Rev, 1994, 94: 77-105.
    [10] Meyers F, Marder S R, Pierce B M, et al. Electric field modulated nonlinear optical properties of donor-acceptor polyenes: Sum-over-states investigation of the relationship between molecular polarizabilities (.alpha., .beta., and .gamma.) and bond length alternation[J]. J Am Chem Soc, 1994, 116(23): 10703-10714.
    [11] Rao V P, Jen A K Y, Chandrasekhar J, et al. The important role of heteroaromatics in the design of efficient second-order nonlinear optical molecules: Theoretical investigation on push-pull heteroaromatic stilbenes[J]. J Am Chem Soc, 1996, 118 (49): 12443-12448.
    [12] Breitung E M, Shu C F, McMahon R J. Thiazole and thiophene analogues of donor?acceptor stilbenes: Molecular hyperpolarizabilities and structure?property relationships[J]. J Am Chem Soc, 2000, 122(6): 1154-1160.
    [13] Albert I D, Marks T J, Ratner M A. Large molecular hyperpolarizabilities: Quantitative analysis of aromaticity and auxiliary donor?acceptor effects[J]. J Am Chem Soc, 1997, 119(28): 6575-6582.
    [14] Yang J S, Liau K L, Li C Y, et al. Meta conjugation effect on the torsional motion of aminostilbenes in the photoinduced intramolecular charge-transfer state[J]. J Am Chem Soc, 2007, 129: 13183-13192.
    [15] Kang H, Facchetti A, Zhu P, et al. Exceptional molecular hyperpolarizabilities in twistedπ-system chromophores[J]. Angew Chem Int Ed Engl, 2005, 44: 7922-7925.
    [16] Kang H, Facchetti A, Jiang H, et al. Ultralarge hyperpolarizability twistedπ-electron system electro-optic chromophores: Synthesis, solid-state and solution-phase structural characteristics, electronic structures, linear and nonlinear optical properties, and computational studies[J]. J Am Chem Soc, 2007, 129(11): 3267-3270.
    [17] Shi Y Q, Zhang C, Zhang H, et al. Low (sub-1-volt) halfwave voltage polymeric electro-opticmodulators achieved by controlling chromophore shape[J]. Science, 2000, 288(5463): 119-122.
    [18] Yan L K, Yang G C, Guang W, et al. Density functional theory study on the first hyperpolarizabilities of organoimido derivatives of hexamolybdates[J]. J Phys Chem B, 2005, 109: 22332-22336. [19] (a) Yan L K, Jin M S, Zhuang J, et al. Theoretical study on the considerable second-order nonlinear optical properties of naphthylimido-substituted hexamolybdates[J]. J Phys Chem A, 2008, 112: 9919-9923. (b Janjua M R S A, Liu C G, Guan W, et al. Prediction of remarkably large second-order nonlinear optical properties of organoimido-substituted hexamolybdates[J]. J Phys Chem A, 2009, 113(15): 3576-3587.
    [20] Guan W, Yang G C, Yan L K, et al. Prediction of second-order optical nonlinearity of trisorganotin-substitutedβ-keggin polyoxotungstate[J]. Inorg Chem, 2006, 45(19): 7864-7868.
    [21] (a) Yang G C, Guang W, Yan L K, et al. Theoretical study on the electronic spectrum and the origin of remarkably large third-order nonlinear optical properties of organoimide derivatives of hexamolybdates[J]. J Phys Chem B, 2006, 110: 23092-23098. (b) Yan L K, Su Z M, Guan W, et al. Why does disubstituted hexamolybdate with arylimido prefer to form an orthogonal derivative? Analysis of stability, bonding character, and electronic properties on molybdate derivatives by density functional theory (DFT) study[J]. J Phys Chem B, 2004, 108: 17337-17343.
    [22] (a) te Velde G, Bickelhaupt F M, Baerends E J, et al. Chemistry with ADF[J]. J Comput Chem, 2001, 22(9): 931-967. (b) Guerra C F, Snijders J G, te Velde G, et al. Towards an order-N DFT method[J]. Theor Chem Acc, 1998, 99(6): 391-403. (c) ADF2008.01, SCM, Theoretical Chemistry, Vrije Universiteit, Amsterdam, The Netherlands, http://www.scm.com
    [23] van Lenthe E, Baerends E J, Snijders J G. Relativistic regular two-component Hamiltonians[J]. J Chem Phys, 1993, 99(9): 4597-4610
    [24] Becke A D. Density-functional exchange-energy approximation with correct asymptotic behavior[J]. Phys Rev A, 1988, 38(6): 3098-3100.
    [25] Perdew J P. Density-functional approximation for the correlation energy of the inhomogeneous electron gas[J]. Phys Rev B, 1986, 33(12): 8822-8824.
    [26] van Gisbergen S J A, Snijders J G, Baerends E J. Implementation of time-dependent density functional response equations[J]. Comp Phys Commun, 1999, 118(2-3): 119-138.
    [27] van Leeuwen R, Baerends E J. Exchange-correlation potential with correct asymptotic behavior[J]. Phys Rev A, 1994, 49(4): 2421-2431.
    [28] van Gisbergen S J A, Osinga V P, Gritsenko O V, et al. Improved density functional theory results for frequency-dependent polarizabilities, by the use of an exchange-correlation potential with correct asymptotic behavior[J]. J Chem Phys, 1996, 105(8): 3142-3151.
    [29] van Gisbergen S J A, Snijders J G, Baerends E J. Time-dependent density functional results for the dynamic hyperpolarizability of C60[J]. Phys Rev Lett, 1997, 78(16): 3097-3100.
    [30] van Gisbergen S J A, Snijders J G, Baerends E J J. Accurate density functional calculations on frequency-dependent hyperpolarizabilities of small molecules[J]. Chem Phys, 1998, 109: 10657-10668.
    [31] (a) Guan W, Yang G C, Yan L K, et al. How do the different defect structures and element substitutions affect the nonlinear optical properties of lacunary keggin polyoxometalates? A DFT study[J]. Eur J Inorg Chem, 2006, 20: 4179-4183. (b) Si Y L, Liu C G, Wang E B, et al. Theoretical study on the two-dimensional second-order nonlinear optical properties: A series of charge transfer covalently bonded organoimido derived hexamolybdates complexes[J]. Theor Chem Account, 2009, 122: 217-226. (c) Zhuang J, Yan L K, Liu C.G, et al. A quantum chemical study of the structure, bonding characteristics and nonlinear optical properties of aryloxido and salicylaldehydo derivatives of [XW5O18]3- (X = Zr or Ti)[J]. Eur J InorgChem, 2009, 31: 2529-2535.
    [32] (a) Janjua M R S A, Liu C G, Guan W, et al. A quantum mechanical study of the second-order nonlinear optical properties of aryldiazenido-substituted hexamolybdates: A surprising charge transfer[J]. Eur J Inorg Chem, 2009, 34: 5181-5188. (b) Mac-Leod Carey D, Mu?oz-Castro A, Bustos C J, et al.π-Donor/Acceptor effect on lindqvist type polyoxomolibdates because of various multiple-bonded nitrogenous ligands[J]. J Phys Chem A, 2007, 111: 6563-6567.
    [33] Xu B, Peng Z, Wei Y, et al. Polyoxometalates covalently bonded with terpyridine ligands[J]. Chem Commun, 2003, 20: 2562-2563.
    [34] (a) Oudar J L, Chemla D S. Hyperpolarizabilities of the nitroanilines and their relations to the excited state dipole moment[J]. J Chem Phys, 1977, 66(6): 2664-2668. (b) Oudar J L. Optical nonlinearities of conjugated molecules. Stilbene derivatives and highly polar aromatic compounds[J]. J Chem Phys, 1977, 67(2): 446-457.
    [1] (a) Kozhevnikov I V. Catalysis by heteropoly acids and multicomponent polyoxometalates in liquid-phase reactions[J]. Chem Rev, 1998, 98 (1): 171-198. (b) Mizuno N, Misono M. Heterogenous catalysis[J]. Chem Rev, 1998, 98 (1): 199-218. (c) Sadakane M, Steckhan E. Electrochemical properties of polyoxometalates as electrocatalysts[J] Chem Rev, 1998, 98 (1): 219-238.
    [2] Rhule J T, Hill C L, Judd D A. Polyoxometaltes in medicine[J]. Chem Rev, 1998, 98(1): 327-357.
    [3] (a) Muller A, Peters F, Pope M.T, et al. Polyoxometalates: Very large clusters nanoscale magnets[J]. Chem Rev, 1998, 98: 239-272. (b) Klemperer W G, Wall CG. Polyoxoanion chemistry moves toward the future: From solids and solutions to surfaces[J]. Chem Rev, 1998, 98: 297-306. (c) Coronado E, Gómez-García C J. Polyoxometalate-based molecular materials[J]. Chem Rev, 1998, 98(1): 273-296. (d) Pope M T, Müller A. Polyoxometalates: From planotic solids to anti-retroviral activity[M]. Kluwer Academic: Dordrecht, The Netherlands, 1994.
    [4] Clemente-Juan J M, Coronado E. Magnetic clusters from polyoxometalate complexes[J]. Coord Chem Rev, 1999, 193-195: 361-394.
    [5] Lindqvist I. The structure of the hexaniobate anion[J]. Ark Kemi, 1952, 5: 247-250.
    [6] (a) Keggin J F. Structure of the molecule of 12-phosphotungstic acid[J]. Nature, 1933, 131(3321): 908-909. (b) Keggin J F. The structure and formula of 12-phosphotungstic acid[J]. Proc R Soc A, 1934, 144: 75-100.
    [7] Dawson B. The structure of the 9(18)-heteropoly anion in potassium 9(18)-tungstophosphate, K6(P2W18O62)·14H2O[J]. Acta Crystallogr, 1953, 6: 113-126.
    [8] Pope M T. Heteropoly and isopoly oxometalates[M]. New York: Springer-Verlag, 1983, 1.
    [9] Hill C L. Ed Chem Rev, 1998, 98: 1 (Special Issue on Polyoxometalates).
    [10] Katsoulis D E. A survey of applications of polyoxometalates[J]. Chem Rev, 1998, 98(1): 359-387.
    [11] Yamase T. Photo- and electrochromism of polyoxometalates and related materials[J]. Chem Rev, 1998, 98(1): 307-325.
    [12] Coronado E, Gómez-García C J. Polyoxometalate-based molecular materials[J]. Chem Rev, 1998, 98(1): 273-296.
    [13] Tripathi A, Hughbanks T, Clearfield A. The first framework solid composed of vanadosilicate clusters[J]. J Am Chem Soc, 2003, 125(35): 10528-10529.
    [14] Guan W, Yan L K, Su Z M, et al. Electronic properties and stability of dititaniumIV substitutedα-Keggin polyoxotungstate with heteroatom phosphorus by DFT[J]. Inorg Chem, 2005, 44(1): 100-107.
    [15] Yan L K, Su Z M, Tan K, et al. Electronic properties of Strandberg anions: A DFT study of [X2Mo5O23]n-, (X = PV, SVI, AsV, SeVI), and [(RP)2Mo5O21]4- (R = H, CH3, C2H5)[J]. Int J Quantum Chem, 2005, 105(1): 37-42.
    [16] Yan L K, Yang G C, Guang W, et al. Density functional theory study on the first hyperpolarizabilities of organoimido derivatives of hexamolybdates[J]. J Phys Chem B, 2005, 109: 22332-22336.
    [17] Guan W, Yan L K, Su Z M, et al. Density functional study of protonation sites ofα-Keggin isopolyanions[J]. Int J Quantum Chem, 2006, 106(8): 1860-1864.
    [18] Yan L K, Su Z M, Guan W, et al. Why does disubstituted hexamolybdate with arylimido prefer to form an orthogonal derivative? Analysis of stability, bonding character, and electronic properties on molybdate derivatives by density functional theory (DFT) study[J]. J Phys Chem B, 2004, 108: 17337-17343.
    [19] Maestre J M, Lopez X, Bo C, et al. A DFT study of the electronic spectrum of theα-Keggin anion [CoIIW12O40]6-[J]. Inorg Chem, 2002, 41(7): 1883-1888.
    [20] Rohmer M M, Bénard M, Blaudeau J P, et al. From Lindqvist and Keggin ions to electronically inverse hosts: AB initio modelling of the structure and reactivity of polyoxometalates[J]. Coord Chem Rev, 1998, 178-180: 1019-1049.
    [21] Maestre J M, Poblet J M, Bo C, et al. Electronic structure of the highly reduced polyoxoanion [PMo12O40(VO)2]5-: A DFT study[J]. Inorg Chem, 1998, 37(13): 3444-3446.
    [22] Lopez X, Maestre J M, Bo C. et al. Electronic properties of polyoxometalates: A DFT study ofα/β-[XM12O40]n- relative stability (M = W, Mo and X a main group element)[J]. J Am Chem Soc, 2001, 123(39): 9571-9576.
    [23] Rohmer M M, Devemy J, Wiest R, et al. Ab Initio modeling of the endohedral reactivity of polyoxometallates: 1. Host?Guest interactions in [RCN (V12O32)4-] (R = H, CH3, C6H5)[J]. J Am Chem Soc, 1996, 118(51): 13007-13014.
    [24] Maestre J M, Lopez X, Bo C, et al. Electronic and Magnetic Properties ofα-Keggin Anions: A DFT Study of [XM12O40]n-, (M = W, Mo; X = AlIII, SiIV, PV, FeIII, CoII, CoIII ) and [SiM11VO40]m- (M = Mo and W)[J]. J Am Chem Soc, 2001, 123(16): 3749-3758.
    [25] Bridgeman A J, Cavigliasso G. Electronic structure of theαandβisomers of [Mo8O26]4-[J]. Inorg Chem, 2002, 41(13): 3500-3507
    [26] Bridgeman A J, Cavigliasso G J. A comparative investigation of structure and bonding in Mo and W [TeM6O24]6- and [PM12O40]3- heteropolyanions[J].Phys Chem A, 2003, 107(34): 6613-6621.
    [27] Poblet J M, Lopez X, Bo C. Ab initio and DFT modelling of complex materials: Towards the understanding of electronic and magnetic properties of polyoxometalates[J]. Chem Soc Rev, 2003, 32(5): 297-308.
    [28] Lopez X, Bo C, Poblet J M. Electron and proton affinity of mixed-addenda Keggin and Wells-Dawson anions[J]. J Am Chem Soc, 2002, 124(42): 12574-12582.
    [29] te Velde G, Bickelhaupt F M, van Gisbergen S J A, et al. Chemistry with ADF[J]. J Comput Chem, 2001, 22(9): 931-967. ( b) Guerra C F, Snijders J G, te Velde G, et al. Towards an order-N DFT method[J]. Theor Chem Acc, 1998, 99(6): 391-403. (c) ADF2006.01[CP], SCM, Theoretical Chemistry, Vrije Universiteit, Amsterdam, The Netherlands, http://www.scm.com
    [30] Vosko S H, Wilk L, Nusair M. Accurate spin-dependent electron liquid correlation energies for local spin-density calculations: A critical analysis[J]. Can J Phys, 1980, 58(8): 1200-1211.
    [31] Becke A D. Density-functional exchange-energy approximation with correct asymptotic-behavior[J]. Phys Rev A, 1988, 38(6): 3098-3100.
    [32] Perdew J P. Density-functional approximation for the correlation-energy of the inhomogenouselectron-gas[J]. Phys Rev B, 1986, 33(12): 8822-8824.
    [33] (a) Chang C, Pelissier M, Durand M. Regular two-component Pauli- like effective hamiltonians in dirac theory[J]. Phys Scr, 1986, 34(5): 394-404.(b) van Lenthe E, Baerends E J, Snijders J G. Relativistic regular 2-component hamiltonians[J]. J Chem Phys, 1993, 99(9): 4597-4610. (c) van Lenthe E, Baerends E J, Snijders J G. Relativistic total energy using regular approximations[J]. J Chem Phys, 1994, 101: 9783-9792. (d) van Lenthe E, van Leeuwen R, Baerends E J, et al. Relativistic regular two-component hamiltonians[J]. Int J Quantum Chem, 1996, 57(3): 281-293.
    [34] Yan L K, Dou Z, Guan W, et al. A DFT study on the electronic and redox properties of [PW11O39(ReN)]n- (n = 3, 4, 5) and [PW11O39(OsN)]2-[J]. Eur J Inorg Chem, 2006, (24): 5126-5129.
    [35] Guan W, Yang G C, Yan L K, et al. How do the different defect structures and element substitutions affect the nonlinear optical properties of lacunary keggin polyoxometalates? A DFT study[J]. Eur J Inorg Chem, 2006, (20): 4179-4183.
    [36] Guan W, Yang G C, Yan L K, et al. Prediction of second-order optical nonlinearity of trisorganotin-substitutedβ-keggin polyoxotungstate[J]. Inorg Chem, 2006, 45(19): 7864-7868.
    [37] Janjua M R S A, Liu C G, Guan W, et al. Prediction of remarkably large second-order nonlinear optical properties of organoimido-substituted hexamolybdates[J]. J Phys Chem A, 2009, 113(15): 3576-3587.
    [38] Mac-Leod Carey D, Mu?oz-Castro A, Bustos C J, et al.π-Donor/Acceptor effect on lindqvist type polyoxomolibdates because of various multiple-bonded nitrogenous ligands[J]. J Phys Chem A, 2007, 111: 6563-6567.

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