铁铁氢化酶活性中心结构与功能模拟
|
摘要
铁铁氢化酶是人类迄今为止发现的最高效的水还原催化剂,其催化速率高达6000-9000s-1。自从其活性中心的单晶结构被测定后,人们围绕它的结构模拟、功能模拟、催化机理做了大量研究工作。通过对一些结构特殊的模型配合物的研究,人们在实验室条件下重现了自然界氢化酶的某些特征。尤其是获得的单电子氧化态中间体与氢化酶活性中心氧化态的构型颇为相像,并表现出相似的电子分布和顺磁特征。相似的构型却未能复制出氢化酶的高催化效率,铁铁模型配合物的功能模拟至今还没有大的突破。相比之下,以钴、镍为中心的金属配合物却往往表现出较好的光和电催化质子还原能力,成为目前氢化酶功能模拟的主要研究方向。
本论文合成并表征了四核和六核铁硫簇合物2、2’和3。这种迷你型的树枝状铁硫配合物表现出与以往报道的多核铁簇合物不同的氧化还原性质。配合物2和3可以在-1.33V～-1.81V(vs Fc+/0)电势范围内分别发生基于金属中心的连续两次和三次的双电子还原反应,在很窄的电势范围内分别获得四个和六个电子。SEC-IR谱图证明配合物2和3的[Fe2S2(CO)6]基团在还原状态下有桥羰基形成。配合物2和3在氧化还原过程中表现出的良好的可逆性,说明苯桥的共轭及刚性对于稳定其还原态物种起到重要的作用。
论文设计合成了一种特殊桥连的氢化酶活性中心模型配合物6,利用“帽”式桥引入不对称的配位环境。来自桥上的斥力使其铁中心相比类似配合物6b更易被氧化。配合物6被氧化后,桥连结构上的酮羰基与溶剂中的水发生加成反应,酮羰基的氧配到铁中心氧化后配体旋转留下的空位上,得到了相对稳定的氧化态产物7。7具有与氢化酶活性中心的一种氧化态(Hoxar)相似的构型、相同的价态,为氢化酶活性中心结构模拟提供了一种新的参考模型。
论文还发现了钴配合物9无论在中性缓冲液中还是在海水中都是一个非常好的电催化还原水的催化剂,其催化水还原过电位低(80mV),活性高,寿命长。在pH7的磷酸缓冲液中,-1.0V电压下,经过20小时的电解,表现出1470mol H2(mol cat)-1h-1(cm2Hg)-’的催化速率,而且没有明显失活。配合物9的另一个优点是能够用廉价的无机盐通过自组装反应得到,这让人联想到自然界的许多金属酶都是通过自组装生成的。这些研究结果表明通过合理设计分子催化剂的结构可以大幅提高电解水制氢的效率,有可能以地球上大量存在的元素作为原料,合成能够代替贵金属铂的高效的分子催化剂,用于水还原产氢。
[FeFe]-hydrogenase ([FeFe]-H2ase) is so far the most efficient catalyst for water reduction, which has a catalytic rate of6000～9000mol H2per second. Chemists have extensively studied its structural and functional mimics and catalytic mechanism since the crystal structure of [FeFe]-H2ase was determined. Chemists have got some features of the hydrogenases existing in nature by studying specially designed model complexes. The intermediates of one electron oxidation state of [FeFe]-H2ases models obtained in lab show almost the same configuration as the Hox state of hydrogenases. These models have similar electron distribution and magnetic property as the Hox. Unfortunately, although the models possess similar structure of [FeFe]-H2ases, they have catalytic properties different from hydrogenases. Some Co and Ni complexes show good photochemical and electrochemical catalytic H2-evolving properties, giving examples for mimicking the function of hydrogenases by small molecules, though no breakthrough is found in functional mimic of [FeFe]-H2ases.
Tetra-and hexanuclear iron-sulfur complexes2,2'and3were prepared and structurally characterized. These mini dendritic iron complexes display redox feature quite different from that of most reported polynucleariron complexes. Complexes2and3display, respectively, two and three consecutive two-electron, metal-center-based reductionevents in the range of-1.33to-1.81V, with relatively narrow potential spans for four-and six-electron transformations. SEC-IR spectra give experimental evidence for the formation of a μ-CO bridge in the two-electron-reduced [Fe2S2(CO)6] unit of2and3. The good reversibility of the reduction processes implies the stabilization of the reduced species of2and3by the conjugated and rigid bridge.
A specially degnined bridge was introduced into the model complex6of [FeFe]-hydrogenase, The "cap-like" bridge resulted in an asymmetric coordination environment of6. The repulsive force from the bridge made the iron center oxidized more easily than its analogue6b. When complex6was oxidized, the ketone carbonyl of the bridge reacted with the water in solvent, and formed a gem-diol sepcies. The oxygen of the ketone coordinates to the open site on the iron center resulting from rotation, thereby forming a covalent bond with the iron atom to afford a relative stable oxidized product7. This complex shows a similar structure with the oxidized state (Hoxair) of the [FeFe]-H2ase active site, and provides a new Fe"Fe" model for the mimic of [FeFe]-H2ases.
A cobalt complex9proves to be an excellent catalyst for electrochemical production of hydrogen both in neutral water and sea water, which displays an extremely low overpotential (80mV) while maintaining high activity and good durability. It displays an activity of1470mol H2(mol cat)-1h-1(cm2Hg)-1over20h CPE (controlled potential electrolysis) experiment at an applied potential of-1.0V in phosphate buffer at pH7, without apparent deactivation. The other merit of this catalyst is its self-assembling property from simple salts of earth-abundant elements, which is reminiscent of self-formation of many metalloenzymes in nature. The discovery of this unusual molecular cobalt catalyst shows promise in using earth-abundant metal-based catalysts as surrogates of precious metal-based ones such as platinum to create highly efficient and economical catalyst systems for water reduction to a sustainable fuel-hydrogen.
本论文合成并表征了四核和六核铁硫簇合物2、2’和3。这种迷你型的树枝状铁硫配合物表现出与以往报道的多核铁簇合物不同的氧化还原性质。配合物2和3可以在-1.33V～-1.81V(vs Fc+/0)电势范围内分别发生基于金属中心的连续两次和三次的双电子还原反应,在很窄的电势范围内分别获得四个和六个电子。SEC-IR谱图证明配合物2和3的[Fe2S2(CO)6]基团在还原状态下有桥羰基形成。配合物2和3在氧化还原过程中表现出的良好的可逆性,说明苯桥的共轭及刚性对于稳定其还原态物种起到重要的作用。
论文设计合成了一种特殊桥连的氢化酶活性中心模型配合物6,利用“帽”式桥引入不对称的配位环境。来自桥上的斥力使其铁中心相比类似配合物6b更易被氧化。配合物6被氧化后,桥连结构上的酮羰基与溶剂中的水发生加成反应,酮羰基的氧配到铁中心氧化后配体旋转留下的空位上,得到了相对稳定的氧化态产物7。7具有与氢化酶活性中心的一种氧化态(Hoxar)相似的构型、相同的价态,为氢化酶活性中心结构模拟提供了一种新的参考模型。
论文还发现了钴配合物9无论在中性缓冲液中还是在海水中都是一个非常好的电催化还原水的催化剂,其催化水还原过电位低(80mV),活性高,寿命长。在pH7的磷酸缓冲液中,-1.0V电压下,经过20小时的电解,表现出1470mol H2(mol cat)-1h-1(cm2Hg)-’的催化速率,而且没有明显失活。配合物9的另一个优点是能够用廉价的无机盐通过自组装反应得到,这让人联想到自然界的许多金属酶都是通过自组装生成的。这些研究结果表明通过合理设计分子催化剂的结构可以大幅提高电解水制氢的效率,有可能以地球上大量存在的元素作为原料,合成能够代替贵金属铂的高效的分子催化剂,用于水还原产氢。
[FeFe]-hydrogenase ([FeFe]-H2ase) is so far the most efficient catalyst for water reduction, which has a catalytic rate of6000～9000mol H2per second. Chemists have extensively studied its structural and functional mimics and catalytic mechanism since the crystal structure of [FeFe]-H2ase was determined. Chemists have got some features of the hydrogenases existing in nature by studying specially designed model complexes. The intermediates of one electron oxidation state of [FeFe]-H2ases models obtained in lab show almost the same configuration as the Hox state of hydrogenases. These models have similar electron distribution and magnetic property as the Hox. Unfortunately, although the models possess similar structure of [FeFe]-H2ases, they have catalytic properties different from hydrogenases. Some Co and Ni complexes show good photochemical and electrochemical catalytic H2-evolving properties, giving examples for mimicking the function of hydrogenases by small molecules, though no breakthrough is found in functional mimic of [FeFe]-H2ases.
Tetra-and hexanuclear iron-sulfur complexes2,2'and3were prepared and structurally characterized. These mini dendritic iron complexes display redox feature quite different from that of most reported polynucleariron complexes. Complexes2and3display, respectively, two and three consecutive two-electron, metal-center-based reductionevents in the range of-1.33to-1.81V, with relatively narrow potential spans for four-and six-electron transformations. SEC-IR spectra give experimental evidence for the formation of a μ-CO bridge in the two-electron-reduced [Fe2S2(CO)6] unit of2and3. The good reversibility of the reduction processes implies the stabilization of the reduced species of2and3by the conjugated and rigid bridge.
A specially degnined bridge was introduced into the model complex6of [FeFe]-hydrogenase, The "cap-like" bridge resulted in an asymmetric coordination environment of6. The repulsive force from the bridge made the iron center oxidized more easily than its analogue6b. When complex6was oxidized, the ketone carbonyl of the bridge reacted with the water in solvent, and formed a gem-diol sepcies. The oxygen of the ketone coordinates to the open site on the iron center resulting from rotation, thereby forming a covalent bond with the iron atom to afford a relative stable oxidized product7. This complex shows a similar structure with the oxidized state (Hoxair) of the [FeFe]-H2ase active site, and provides a new Fe"Fe" model for the mimic of [FeFe]-H2ases.
A cobalt complex9proves to be an excellent catalyst for electrochemical production of hydrogen both in neutral water and sea water, which displays an extremely low overpotential (80mV) while maintaining high activity and good durability. It displays an activity of1470mol H2(mol cat)-1h-1(cm2Hg)-1over20h CPE (controlled potential electrolysis) experiment at an applied potential of-1.0V in phosphate buffer at pH7, without apparent deactivation. The other merit of this catalyst is its self-assembling property from simple salts of earth-abundant elements, which is reminiscent of self-formation of many metalloenzymes in nature. The discovery of this unusual molecular cobalt catalyst shows promise in using earth-abundant metal-based catalysts as surrogates of precious metal-based ones such as platinum to create highly efficient and economical catalyst systems for water reduction to a sustainable fuel-hydrogen.
引文
[1]Adams M. W. W. The structure and mechanism of iron-hydrogenases [J]. Biochim. Biophys. Acta, 1990,1020:115-145.
[2]Adams M. W., Stiefel E. I. Organometallic iron:the key to biological hydrogen metabolism [J]. Curr. Opin. Chem. Biol.,2000,4(2):214-220.
[3]Huynh B. H., Czechowski M. H., Kruger H. J., et al. Desulfovibrio vulgaris hydrogenase:a nonheme iron enzyme lacking nickel that exhibits anomalous EPR and Mossbauer spectra [J]. Proc. Natl. Acad. Sci. U. S. A.,1984,81(12):3728-3732.
[4]Adams M. W., Mortenson L. E. The physical and catalytic properties of hydrogenase Ⅱ of Clostridium pasteurianum. A comparison with hydrogenase Ⅰ [J]. J. Biol. Chem.,1984,259(11):7045-7055.
[5]Albracht S. P. Nickel hydrogenases:in search of the active site [J]. Biochim. Biophys. Acta.,1994, 1188(3):167-204.
[6]Peters J. W. Structure and mechanism of iron-only hydrogenases [J]. Curr. Opin. Struct. Biol.,1999, 9(6):670-676.
[7]Frey M. Hydrogenases:hydrogen-activating enzymes [J]. Chembiochem.,2002,3(2-3):153-160.
[8]Peters J. W., Lanzilotta W. N., Lemon B. J., et al. X-ray crystal structure of the Fe-only hydrogenase (Cpl) from Clostridium pasteurianum to 1.8 angstrom resolution [J]. Science,1998,282(5395): 1853-1858.
[9]Nicolet Y., Piras C., Legrand P., et al. Desulfovibrio desulfuricans iron hydrogenase:the structure shows unusual coordination to an active site Fe binuclear center [J]. Structure,1999,7(1):13-23.
[10]Tran P. D., Le Goff A., Heidkamp J., et al. Noncovalent modification of carbon nanotubes with pyrene-functionalized nickel complexes:carbon monoxide tolerant catalysts for hydrogen evolution and uptake [J]. Angew. Chem. Int. Ed.,2011,50(6):1371-1374.
[11]Nicolet Y., De Lacey A. L., Vernede X., et al. Crystallographic and FTIR spectroscopic evidence of changes in Fe coordination upon reduction of the active site of the Fe-only hydrogenase from Desulfovibrio desulfuricans [J]. J. Am. Chem. Soc,2001,123(8):1596-1601.
[12]Lemon B. J., Peters J. W. Binding of exogenously added carbon monoxide at the active site of the iron-only hydrogenase (CpI) from Clostridium pasteurianum [J]. Biochemistry,1999,38(40): 12969-12973.
[13]Lacey A. L. D., Stadler C., Cavazza C., et al. FTIR Characterization of the Active Site of the Fe-hydrogenase from Desulfovibrio desulfuricans. [J]. J. Am. Chem.Soc,2000,122:11232-11233.
[14]Chen Z., Lemon B. J., Huang S., et al. Infrared studies of the CO-inhibited form of the Fe-only hydrogenase from Clostridium pasteurianum Ⅰ:examination of its light sensitivity at cryogenic temperatures [J]. Biochemistry,2002,41(6):2036-2043.
[15]Fan H. J., Hall M. B. High-spin Ni(Ⅱ), a surprisingly good structural model for [NiFe] hydrogenase [J]. J. Am. Chem. Soc.,2002,124(3):394-395.
[16]Pereira A. S., Tavares P., Moura I., et al. Mossbauer characterization of the iron-sulfur clusters in Desulfovibrio vulgaris hydrogenase [J]. J. Am. Chem. Soc.,2001,123(12):2771-2782.
[17]Bennett B., Lemon B. J., Peters J. W. Reversible carbon monoxide binding and inhibition at the active site of the Fe-only hydrogenase [J]. Biochemistry,2000,39(25):7455-7460.
[18]De Lacey A. L., Stadler C., Cavazza C., et al. FTIR Characterization of the Active Site of the Fe-hydrogenase from Desulfovibrio desulfuricans [J]. J. Am. Chem. Soc.,2000,122(45): 11232-11233.
[19]Popescu C. V., Munck E. J. Am. Chem. Soc.,1999,121:7877-7884.
[20]Lyon E. J., Georgakaki I. P., Reibenspies J. H., et al. Carbon Monoxide and Cyanide Ligands in a Classical Organometallic Complex Model for Fe-Only Hydrogenase [J]. Angew. Chem. Int. Ed., 1999,38(21):3178-3180.
[21]Schmidt M., Contakes S. M., Rauchfuss T. B. J. Am. Chem. Soc.,1999,121:9736-9737.
[22]Le Cloirec A., C. Davies S., J. Evans D., et al. A di-iron dithiolate possessing structural elements of the carbonyl/cyanide sub-site of the H-centre of Fe-only hydrogenase [J]. Chem. Commun.,1999, 0(22):2285-2286.
[23]Fan H. J., Hall M. B. A capable bridging ligand for Fe-only hydrogenase:density functional calculations of a low-energy route for heterolytic cleavage and formation of dihydrogen [J]. J. Am. Chem. Soc.,2001,123(16):3828-3829.
[24]Li H., Rauchfuss T. B. Iron carbonyl sulfides, formaldehyde, and amines condense to give the proposed azadithiolate cofactor of the Fe-only hydrogenases [J]. J. Am. Chem. Soc.,2002,124(5): 726-727.
[25]Ott S., Kritikos M., Akermark B., et al. A biomimetic pathway for hydrogen evolution from a model of the iron hydrogenase active site [J]. Angew. Chem. Int. Ed.,2004,43(8):1006-1009.
[26]Felton G. A., Vannucci A. K., Chen J., et al. Hydrogen generation from weak acids:electrochemical and computational studies of a diiron hydrogenase mimic [J]. J. Am. Chem. Soc.,2007,129(41): 12521-12530.
[27]Darchen A., Mousser H., Patin H. Two-electron transfer catalysis of carbon monoxide exchangel with a ligand in hexacarbonyldi-iron compounds [([μ-RS)2Fe2(CO)6] [J]. J. Chem. Soc, Chem. Commun.,1988,0(14):968-970.
[28]Chong D., Georgakaki I. P., Mejia-Rodriguez R., et al. Electrocatalysis of hydrogen production by active site analogues of the iron hydrogenase enzyme:structure/function relationships [J]. Dalton Trans.,2003,0(21):4158-4163.
[29]Borg S. J., Behrsing T., Best S. P., et al. Electron transfer at a dithiolate-bridged diiron assembly: electrocatalytic hydrogen evolution [J]. J. Am. Chem. Soc.,2004,126(51):16988-16999.
[30]Borg S. J., Bondin M.I., Best S. P., et al. Electrocatalytic proton reduction by dithiolate-bridged diiron carbonyl complexes:a connection to the H-cluster [J]. Biochem. Soc. Trans.,2005,33(Pt 1): 3-6.
[31]Singh P. S., Rudbeck H. C., Huang P., et al. (1,0) Mixed-valence state of a diiron complex with pertinence to the [FeFe]-hydrogenase active site:an IR, EPR, and computational study [J]. Inorg. Chem.,2009,48(23):10883-10885.
[32]Best S. P., Borg S. J., White J. M., et al. On the structure of a proposed mixed-valent analogue of the diiron subsite of [FeFe]-hydrogenase [J]. Chem. Commun.,2007,42:4348-4350.
[33]Wright R. J., Zhang W., Yang X., et al. Isolation, observation, and computational modeling of proposed intermediates in catalytic proton reductions with the hydrogenase mimic Fe2(CO)6S2C6H4 [J]. Dalton Trans.,2012,41(1):73-82.
[34]Darensbourg M. Y., Lyon E. J., Zhao X., et al. The organometallic active site of [FeFe]-hydrogenase: models and entatic states [J]. Proc. Natl. Acad. Sci. U. S. A.,2003,100(7):3683-3688.
[35]Liu T., Darensbourg M. Y. A mixed-valent, Fe(Ⅱ)Fe(Ⅰ),diiron complex reproduces the unique rotated state of the [FeFe]-hydrogenase active site [J]. J. Am. Chem. Soc.,2007,129(22): 7008-7009.
[36]Justice A. K., Rauchfuss T.B., Wilson S. R. Unsaturated, mixed-valence diiron dithiolate model for the H(ox) state of the [FeFe]-hydrogenase [J]. Angew. Chem. Int. Ed.,2007,46(32):6152-6154.
[37]Justice A. K., De Gioia L., Nilges M. J., et al. Redox and structural properties of mixed-valence models for the active site of the [FeFe]-hydrogenase:progress and challenges [J]. Inorg. Chem., 2008,47(16):7405-7414.
[38]Singleton M. L., Bhuvanesh N., Reibenspies J. H., et al. Synthetic support of de novo design: sterically bulky [FeFe]-hydrogenase models [J]. Angew. Chem. Int. Ed.,2008,47(49):9492-9495.
[39]Camara J. M., Rauchfuss T. B. Mild redox complementation enables H2 activation by [FeFe]-hydrogenase models [J]. J. Am. Chem. Soc.,2011,133(21):8098-8101.
[40]Olsen M. T., Rauchfuss T. B., Wilson S. R. Role of the azadithiolate cofactor in models for [FeFe]-hydrogenase:novel structures and catalytic implications [J]. J. Am. Chem. Soc.,2010, 132(50):17733-17740.
[41]Olsen M. T., Barton B. E., Rauchfuss T. B. Hydrogen activation by biomimetic diiron dithiolates [J]. Inorg. Chem.,2009,48(16):7507-7509.
[42]Razavet M., Borg S. J., George S. J., et al. Transient FTIR spectroelectrochemical and stopped-flow detection of a mixed valence{Fe(Ⅰ)-Fe(Ⅱ)} bridging carbonyl intermediate with structural elements and spectroscopic characteristics of the di-iron sub-site of all-iron hydrogenase [J]. Chem. Commun.,2002,7:700-701.
[43]Erdem O. F., Schwartz L., Stein M., et al. A model of the [FeFe]-hydrogenase active site with a biologically relevant azadithiolate bridge:a spectroscopic and theoretical investigation [J]. Angew. Chem. Int. Ed.,2011,50(6):1439-1443.
[44]Mealli C., Rauchfuss T. B. Models for the hydrogenases put the focus where it should be-hydrogen [J]. Angew. Chem. Int. Ed.,2007,46(47):8942-8944.
[45]Carroll M. E., Barton B. E., Rauchfuss T. B., et al. Synthetic models for the active site of the [FeFe]-hydrogenase:catalytic proton reduction and the structure of the doubly protonated intermediate [J]. J. Am. Chem. Soc.,2012,134(45):18843-18852.
[46]Silakov A., Reijerse E. J., Albracht S. P., et al. The electronic structure of the H-cluster in the [FeFe]-hydrogenase from Desulfovibrio desulfuricans:a Q-band 57Fe-ENDOR and HYSCORE study [J]. J. Am. Chem. Soc.,2007,129(37):11447-11458.
[47]Adamska A., Silakov A., Lambertz C., et al. Identification and characterization of the "super-reduced" state of the H-cluster in [FeFe]-hydrogenase:a new building block for the catalytic cycle? [J]. Angew. Chem. Int. Ed.,2012,51(46):11458-11462.
[48]Baffert C., Artero V., Fontecave M. Cobaloximes as functional models for hydrogenases.2. Proton electroreduction catalyzed by difluoroborylbis(dimethylglyoximato)cobalt(Ⅱ) complexes in organic media [J]. Inorg. Chem.,2007,46(5):1817-1824.
[49]Hu X., Brunschwig B. S., Peters J. C. Electrocatalytic hydrogen evolution at low overpotentials by cobalt macrocyclic glyoxime and tetraimine complexes [J]. J. Am. Chem. Soc.,2007,129(29): 8988-8998.
[50]Razavet M., Artero V., Fontecave M. Proton electroreduction catalyzed by cobaloximes:functional models for hydrogenases [J]. Inorg. Chem.,2005,44(13):4786-4795.
[51]Collman J. P., Cawse J. N., Kang J. W. Synthesis of sigma-bonded allenyl complexes of iridium, platinum, and cobalt [J]. Inorg. Chem.,1969,8(12):2574-2579.
[52]Schrauzer G. N., Kratel G. Organometallverbindungen von Cobaloximen und vom Vitamin B12 [J]. Angew. Chem.,1965,77(3):130-130.
[53]Jacques P. A., Artero V., Pecaut J., et al. Cobalt and nickel diimine-dioxime complexes as molecular electrocatalysts for hydrogen evolution with low overvoltages [J]. Proc. Natl. Acad. Sci. U. S. A., 2009,106(49):20627-20632.
[54]Curtis C. J., Miedaner A., Ellis W. W., et al. Measurement of the hydride donor abilities of [HM(diphosphine)2]+complexes (M=Ni, Pt) by heterolytic activation of hydrogen [J]. J. Am. Chem. Soc.,2002,124(9):1918-1925.
[55]Curtis C. J., Miedaner A., Ciancanelli R., et al. [Ni(Et2PCH2NMeCH2PEt2)2]2+ as a functional model for hydrogenases [J]. Inorg. Chem.,2003,42(1):216-227.
[56]Wilson A. D., Newell R. H., Mcnevin M. J., et al. Hydrogen oxidation and production using nickel-based molecular catalysts with positioned proton relays [J]. J. Am. Chem. Soc.,2006,128(1): 358-366.
[57]Wilson A. D., Fraze K., Twamley B., et al. The role of the second coordination sphere of [Ni(PCy2NBz2)2](BF4)2 in reversible carbon monoxide binding [J]. J. Am. Chem. Soc.,2008,130(3): 1061-1068.
[58]Yang J. Y., Chen S., Dougherty W. G., et al. Hydrogen oxidation catalysis by a nickel diphosphine complex with pendant tert-butyl amines [J]. Chem. Commun.,2010,46(45):8618-8620.
[59]Galan B. R., Schoffel J., Linehan J. C., et al. Electrocatalytic oxidation of formate by [Ni(P(R)2N(R')2)2(CH3CN)]2+ complexes [J]. J. Am. Chem. Soc.,2011,133(32):12767-12779.
[60]Kilgore U. J., Stewart M. P., Helm M. L., et al. Studies of a series of [Ni(P(R)2N(Ph)2)2(CH3CN)]2+ complexes as electrocatalysts for H2 production:substituent variation at the phosphorus atom of the P2N2 ligand [J]. Inorg. Chem.,2011,50(21):10908-10918.
[61]Liu T., Chen S., O'hagan M. J., et al. Synthesis, characterization, and reactivity of Fe complexes containing cyclic diazadiphosphine ligands:the role of the pendant base in heterolytic cleavage of H2 [J]. J. Am. Chem. Soc.,2012,134(14):6257-6272.
[62]O'hagan M., Ho M. H., Yang J. Y., et al. Proton delivery and removal in [Ni(P(R)2N(R')2)2]2+ hydrogen production and oxidation catalysts [J]. J. Am. Chem. Soc.,2012,134(47):19409-19424.
[63]Pool D. H., Stewart M. P., O'hagan M., et al. Acidic ionic liquid/water solution as both medium and proton source for electrocatalytic H2 evolution by [Ni(P2N2)2]2+ complexes [J]. Proc. Natl. Acad. Sci. U. S. A.,2012,109(39):15634-15639.
[64]Raugei S., Chen S., Ho M. H., et al. The role of pendant amines in the breaking and forming of molecular hydrogen catalyzed by nickel complexes [J]. Chemistry,2012,18(21):6493-6506.
[65]Shaw W. J., Helm M. L., Dubois D. L. A modular, energy-based approach to the development of nickel containing molecular electrocatalysts for hydrogen production and oxidation [J]. Biochim. Biophys. Acta.,2013, doi:10.1016/j.bbabio.2013.01.003.
[66]Helm M. L., Stewart M. P., Bullock R. M., et al. A synthetic nickel electrocatalyst with a turnover frequency above 100,000 s-1 for H2 production [J]. Science,2011,333(6044):863-866.
[67]Wang M., Chen L., Sun L. Recent progress in electrochemical hydrogen production with earth-abundant metal complexes as catalysts [J]. Energy Environ. Sci,2012,5(5):6763-6778.
[68]Karunadasa H. I., Chang C. J., Long J. R. A molecular molybdenum-oxo catalyst for generating hydrogen from water [J]. Nature,2010,464(7293):1329-1333.
[69]Karunadasa H. I., Montalvo E., Sun Y., et al. A molecular MoS(2) edge site mimic for catalytic hydrogen generation [J]. Science,2012,335(6069):698-702.
[70]Sun Y., Bigi J. P., Piro N. A., et al. Molecular cobalt pentapyridine catalysts for generating hydrogen from water [J]. J. Am. Chem. Soc.,2011,133(24):9212-9215.
[71]Capon J.-F., Gloaguen F., Petillon F. Y., et al. Electron and proton transfers at diiron dithiolate sites relevant to the catalysis of proton reduction by the [FeFe]-hydrogenases [J]. Coord. Chem. Rev, 2009,253(9-10):1476-1494.
[72]Barton B. E., Rauchfuss T. B. Terminal hydride in [FeFe]-hydrogenase model has lower potential for H2 production than the isomeric bridging hydride [J]. Inorg. Chem.,2008,47(7):2261-2263.
[73]Ezzaher S., Capon J.-F., Gloaguen F., et al. Electron-Transfer-Catalyzed rearrangement of unsymmetrically substituted diiron dithiolate complexes related to the active site of the [FeFe]-Hydrogenases [J]. Inorg. Chem.,2007,46(23):9863-9872.
[74]Barton B. E., Olsen M. T., Rauchfuss T. B. Aza- and oxadithiolates are probable proton relays in functional models for the [FeFe]-hydrogenases [J]. J. Am. Chem. Soc.,2008,130(50): 16834-16835.
[75]Silakov A., Wenk B., Reijerse E., et al. 14N-HYSCORE investigation of the H-cluster of [FeFe]-hydrogenase:evidence for a nitrogen in the dithiol bridge [J]. Phys. Chem. Chem. Phys.,2009, 11(31):6592-6599.
[76]Erdem F., Schwartz L., Stein M., et al. A model of the [FeFe]-hydrogenase active site with a biologically relevant azadithiolate bridge:a spectroscopic and theoretical investigation [J]. Angew. Chem. Int. Ed.,2011,50(6):1439-1443.
[77]Thomas C. M., Liu T., Hall M. B., et al. Series of mixed valent Fe(Ⅱ)Fe(Ⅰ) complexes that model the Hox state of [FeFe]-hydrogenase:redox properties, density-functional theory investigation, and reactivities with extrinsic CO [J]. Inorg. Chem.,2008,47(15):7009-7024.
[78]Tard C., Liu X., Ibrahim S. K., et al. Synthesis of the H-cluster framework of iron-only hydrogenase [J]. Nature,2005,433(7026):610-613.
[79]Liu Y.-C., Lee C.-H., Lee G.-H., et al. Influence of a Redox-Active Phosphane Ligand on the Oxidations of a Diiron Core Related to the Active Site of Fe-Only Hydrogenase [J]. Eur. J. Inorg. Chem.,2011,2011 (7):1155-1162.
[80]Zeng X., Li Z., Xiao Z., et al. Using pendant ferrocenyl group(s) as an intramolecular standard to probe the reduction of diiron hexacarbonyl model complexes for the sub-unit of [FeFe]-hydrogenase [J]. ElectroChem. Commun.,2010,12(3):342-345.
[81]Si Y., Charreteur K., Capon J.-F., et al. Non-innocent bma ligand in a dissymetrically disubstituted diiron dithiolate related to the active site of the [FeFe]-hydrogenases [J]. J. Inorg. Biochem.,2010, 104(10):1038-1042.
[82]Camara J. M., Rauchfuss T. B. Combining acid-base, redox and substrate binding functionalities to give a complete model for the [FeFe]-hydrogenase [J]. Nat. Chem.,2012,4(1):26-30.
[83]Le Goff A., Artero V., Jousselme B., et al. From hydrogenases to noble metal-free catalytic nanomaterials for H2 production and uptake [J]. Science,2009,326(5958):1384-1387.
[84]Andreiadis E. S., Jacques P. A., Tran P. D., et al. Molecular engineering of a cobalt-based electrocatalytic nanomaterial for H2 evolution under fully aqueous conditions [J]. Nat. Chem.,2013, 5(1):48-53.
[85]Tran P. D., Le Goff A., Heidkamp J., et al. Noncovalent modification of carbon nanotubes with pyrene-functionalized nickel complexes:carbon monoxide tolerant catalysts for hydrogen evolution and uptake [J]. Angew. Chem. Int. Ed.,2011,50(6):1371-1374.
[86]Fihri A., Artero V., Razavet M., et al. Cobaloxime-based photocatalytic devices for hydrogen production [J]. Angew. Chem. Int. Ed.,2008,47(3):564-567.
[87]Li X., Wang M., Zhang S., et al. Noncovalent Assembly of a Metalloporphyrin and an Iron Hydrogenase Active-Site Model:Photo-Induced Electron Transfer and Hydrogen Generation [J]. J. Phys. Chem. B,2008,112(27):8198-8202
[88]Zhang P., Wang M., Li C., et al. Photochemical H2 production with noble-metal-free molecular devices comprising a porphyrin photosensitizer and a cobaloxime catalyst [J]. Chem. Commun., 2010,46(46):8806-8808.
[89]Duan L., Bozoglian F., Mandal S., et al. A molecular ruthenium catalyst with water-oxidation activity comparable to that of photosystem I [J]. Nat. Chem.,2011,4(5):418-423.
[90]Kanan M. W., Nocera D. G. In situ formation of an oxygen-evolving catalyst in neutral water containing phosphate and Co2+[J]. Science,2008,321(5892):1072-1075.
[91]Conway B. E., Bai L. H2 evolution kinetics at high activity Ni-Mo-Cd electrocoated cathodes and its relation to potential dependence of sorption of H [J]. Int. J. Hydrogen Energy,1986,11(8):533-540.
[92]Reece S. Y., Hamel J. A., Sung K., et al. Wireless solar water splitting using silicon-based semiconductors and earth-abundant catalysts [J]. Science,2011,334(6056):645-648.
[93]Diallo A. K., Daran J. C., Varret F., et al. How do redox groups behave around a rigid molecular platform? Hexa(ferrocenylethynyl)benzenes and their "electrostatic" redox chemistry [J]. Angew. Chem. Int. Ed.,2009,48(17):3141-3145.
[94]Astruc D. Ferrocenyl dendrimers:multi-electron redox reagents and their applications [J]. New J. Chem.,2011,35(4):764-772.
[95]Zhao Q., Harris T. D., Betley T. A. [((H)L)2Fe6(NCMe)m]n+(m=0,2,4,6; n=-1,0,1,2,3,4,6): an electron-transfer series featuring octahedral Fe6 clusters supported by a hexaamide ligand platform [J]. J. Am. Chem. Soc.,2011,133(21):8293-8306.
[96]Felton G. A. N., Mebi C. A., Petro B. J., et al. Review of electrochemical studies of complexes containing the Fe2S2 core characteristic of [FeFe]-hydrogenases including catalysis by these complexes of the reduction of acids to form dihydrogen [J]. J. Organomet. Chem.,2009,694(17): 2681-2699.
[97]Maiolo F., Testaferri L., Tiecco M., et al. Fragmentation of aryl alkyl sulfides. A simple, one-pot synthesis of polymercaptobenzenes from polychlorobenzenes [J]. J. Org. Chem.,1981,46(15): 3070-3073.
[98]Yip H. K., Schier A., Riede J., et al. Benzenehexathiol as a template rim for a golden wheel: synthesis and structure of [{CSAu(PPh3)}6] [J]. J. Chem. Soc., Dalton Trans.,1994,0(15): 2333-2334
[99]Capon J. F., Gloaguen F., Schollhammer P., et al. Di-iron aza diphosphido complexes:mimics for the active site of Fe-only hydrogenase, and effects of changing the coordinating atoms of the bridging ligand in [Fe2[μ-(ECH2)2NR](CO)6] [J]. J. Electroanal. Chem.,2004,566:241-247.
[100]Gloaguen F., Morvan D., Capon J. F., et al. Bioactive capsular polysaccharide from the thermophilic cyanophyte/cyanobacterium mastigocladus laminosus-cytotoxic properties [J]. J. Electroanal. Chem.,2007,603:15-20.
[101]Chong D., Georgakaki I. P., Mejia-Rodriguez R., et al. Electrocatalysis of hydrogen production by active site analogues of the iron hydrogenase enzyme:structure/function relationships [J]. Dalton Trans.,2003,4158-4163.
[102]Lyon E. J., Georgakaki I. P., Reibenspies J. H., et al. Carbon monoxide and cyanide ligands in a classical organometallic complex model for Fe-only hydrogenase [J]. Angew. Chem. Int. Ed.,1999, 38:3178-3180.
[103]Orain P.-Y., Capon J.-F., Gloaguen F., et al. Tuning of electron transfer in diiron azo-bridged complexes relevant to hydrogenases [J]. Int. J. Hydrogen. Energy.,2010,35(19):10797-10802.
[104]Chen J., Vannucci A. K., Mebi C. A., et al. Synthesis of diiron hydrogenase mimics bearing hydroquinone and related ligands. electrochemical and computational studies of the mechanism of hydrogen production and the role of O-H-S hydrogen bonding [J]. Organometallics,2010,29(21): 5330-5340.
[105]Diallo A. K., Daran J.-C., Varret F., et al. How do redox groups behave around a rigid molecular platform? hexa(ferrocenylethynyl)benzenes and their "electrostatic" redox chemistry [J]. Angew. Chem. Int. Ed.,2009,48(17):3141-3145.
[106]Zhao Q., Harris T. D., Betley T. A. [(HL)2Fe6(NCMe)m]n+(m= 0,2,4,6; n=-1,0,1,2,3,4,6): An electron-transfer series featuring octahedral Fe6 clusters supported by a hexaamide ligand platform [J]. J. Am. Chem. Soc.,2011,133(21):8293-8306.
[107]Li P., Wang M., Pan J., et al. [FeFe]-Hydrogenase active site models with relatively low reduction potentials:Diiron dithiolate complexes containing rigid bridges [J]. J. Inorg. Biochem.,2008, 102(4):952-959.
[108]Boelens M., De Kimpe N., Keppens M., et al. Proof of the stereochemistry of cis-2,5-dibromocyclopentanone [J]. J. Org. Chem.,1994,59(15):4170-4171.
[109]Wright J. A., Pickett C. J. Protonation of a subsite analogue of [FeFe]-hydrogenase:mechanism of a deceptively simple reaction revealed by time-resolved IR spectroscopy [J]. Chem. Commun., 2009,0(38):5719-5721.
[110]Song L.-C., Li C.-G., Gao J., et al. Synthesis, Structure, and Electrocatalysis of Diiron C-Functionalized Propanedithiolate (PDT) Complexes Related to the Active Site of [FeFe]-Hydrogenases [J]. Inorg. Chem.,2008,47(11):4545-4553.
[111]Chen X.-D., Du M., He F., et al. Ligand behavior of 2,6-pyridinediylbis(2-pyridinyl)methanone in solvent-controlled formation of iron(Ⅲ) complexes:A novel asymmetric quasi-linear trinuclear core containing an eight-coordinate iron center [J]. Polyhedron,2005,24(9):1047-1053.
[112]Cranswick M. A., Gruhn N. E., Enemark J. H., et al. Electronic structure of the d bent-metallocene Cp(2)VCl(2):A photoelectron and density functional study [J]. J. Organomet. Chem.,2008, 693(8-9):1621-1627.
[113]Jeffery J. C., Odell B., Stevens N., et al. Self assembly of a novel water soluble iron macrocyclic phosphine complex from tetrakis(hydroxymethyl)phosphonium sulfate and iron ammonium sulfate: single crystal X-ray structure of the complex [Fe(HO){RP(CHN(CHPR)CH)PR}]SO4·4H2O (R= CH2OH) [J]. Chem. Commun.,2000,0(1):101-102.
[114]Bakac A., Brynildson M. E., Espenson J. H. Characterization of the structure, properties, and reactivity of a cobalt(Ⅱ) macrocyclic complex [J]. Inorg. Chem.,1986,25(23):4108-4114.
[115]Merki D., Vrubel H., Rovelli L., et al. Fe, Co, and Ni ions promote the catalytic activity of amorphous molybdenum sulfide films for hydrogen evolution [J]. Chem. Sci,2012,3(8): 2515-2525.
[116]Collin J. P., Jouaiti A., Sauvage J. P. Electrocatalytic properties of (tetraazacyclotetradecane)nickel2+ and Ni2(biscyclam)4+ with respect to carbon dioxide and water reduction [J]. Inorg. Chem.,1988,27(11):1986-1990.
[117]Bernhardt P. V., Jones L. A. Electrochemistry of Macrocyclic Cobalt(Ⅲ/Ⅱ) Hexaamines: Electrocatalytic Hydrogen Evolution in Aqueous Solution [J]. Inorg. Chem.,1999,38(22): 5086-5090.
[118]Singh W. M., Baine T., Kudo S., et al. Electrocatalytic and photocatalytic hydrogen production in aqueous solution by a molecular cobalt complex [J]. Angew. Chem. Int. Ed.,2012,51(24): 5941-5944.
[119]Houlding V., Geiger T., KoLle U., et al. Electrochemical and photochemical investigations of two novel electron relays for hydrogen generation from water [J]. J. Chem. Soc., Chem. Commun.,1982, 12):681-683.
[120]Koelle U., Paul S. Electrochemical reduction of protonated cyclopentadienylcobalt phosphine complexes [J]. Inorg. Chem.,1986,25(16):2689-2694.
[121]Stubbert B. D., Peters J. C., Gray H. B. Rapid water reduction to H2 catalyzed by a cobalt bis(iminopyridine) complex [J]. J. Am. Chem. Soc.,2011,133(45):18070-18073.
[122]Anxolabehere-Mallart E., Costentin C., Fournier M., et al. Boron-capped tris(glyoximato) cobalt clathrochelate as a precursor for the electrodeposition of nanoparticles catalyzing H2 evolution in water [J]. J. Am. Chem. Soc.,2012,134(14):6104-6107.
[123]Artero V., Fontecave M. Solar fuels generation and molecular systems:is it homogeneous or heterogeneous catalysis? [J]. Chem. Soc. Rev.,2013,42(6):2338-2356.
[124]Muresan N. M., Willkomm J., Mersch D., et al. Immobilization of a molecular cobaloxime catalyst for hydrogen evolution on a mesoporous metal oxide electrode [J]. Angew. Chem. Int. Ed.,2012, 51(51):12749-12753.
[125]Kellett R. M., Spiro T. G. Cobalt porphyrin electrode films as hydrogen catalysts [J]. Inorg. Chem., 1985,24:2378-2382.
[126]Bujno K., Bilewicz R., Siegfried L., et al. Effects of ligand structure on the adsorption of nickel tetraazamacrocyclic complexes and electrocatalytic CO2 reduction [J]. Electroanal. Chem.,1998, 445:47-53.
[127]Schneider J., Jia H., Kobiro K., et al. Nickel(Ⅱ) macrocycles:highly efficient electrocatalysts for the selective reduction of CO2 to CO [J]. Energy Environ. Sci.,2012,5(11):9502-9510.
[2]Adams M. W., Stiefel E. I. Organometallic iron:the key to biological hydrogen metabolism [J]. Curr. Opin. Chem. Biol.,2000,4(2):214-220.
[3]Huynh B. H., Czechowski M. H., Kruger H. J., et al. Desulfovibrio vulgaris hydrogenase:a nonheme iron enzyme lacking nickel that exhibits anomalous EPR and Mossbauer spectra [J]. Proc. Natl. Acad. Sci. U. S. A.,1984,81(12):3728-3732.
[4]Adams M. W., Mortenson L. E. The physical and catalytic properties of hydrogenase Ⅱ of Clostridium pasteurianum. A comparison with hydrogenase Ⅰ [J]. J. Biol. Chem.,1984,259(11):7045-7055.
[5]Albracht S. P. Nickel hydrogenases:in search of the active site [J]. Biochim. Biophys. Acta.,1994, 1188(3):167-204.
[6]Peters J. W. Structure and mechanism of iron-only hydrogenases [J]. Curr. Opin. Struct. Biol.,1999, 9(6):670-676.
[7]Frey M. Hydrogenases:hydrogen-activating enzymes [J]. Chembiochem.,2002,3(2-3):153-160.
[8]Peters J. W., Lanzilotta W. N., Lemon B. J., et al. X-ray crystal structure of the Fe-only hydrogenase (Cpl) from Clostridium pasteurianum to 1.8 angstrom resolution [J]. Science,1998,282(5395): 1853-1858.
[9]Nicolet Y., Piras C., Legrand P., et al. Desulfovibrio desulfuricans iron hydrogenase:the structure shows unusual coordination to an active site Fe binuclear center [J]. Structure,1999,7(1):13-23.
[10]Tran P. D., Le Goff A., Heidkamp J., et al. Noncovalent modification of carbon nanotubes with pyrene-functionalized nickel complexes:carbon monoxide tolerant catalysts for hydrogen evolution and uptake [J]. Angew. Chem. Int. Ed.,2011,50(6):1371-1374.
[11]Nicolet Y., De Lacey A. L., Vernede X., et al. Crystallographic and FTIR spectroscopic evidence of changes in Fe coordination upon reduction of the active site of the Fe-only hydrogenase from Desulfovibrio desulfuricans [J]. J. Am. Chem. Soc,2001,123(8):1596-1601.
[12]Lemon B. J., Peters J. W. Binding of exogenously added carbon monoxide at the active site of the iron-only hydrogenase (CpI) from Clostridium pasteurianum [J]. Biochemistry,1999,38(40): 12969-12973.
[13]Lacey A. L. D., Stadler C., Cavazza C., et al. FTIR Characterization of the Active Site of the Fe-hydrogenase from Desulfovibrio desulfuricans. [J]. J. Am. Chem.Soc,2000,122:11232-11233.
[14]Chen Z., Lemon B. J., Huang S., et al. Infrared studies of the CO-inhibited form of the Fe-only hydrogenase from Clostridium pasteurianum Ⅰ:examination of its light sensitivity at cryogenic temperatures [J]. Biochemistry,2002,41(6):2036-2043.
[15]Fan H. J., Hall M. B. High-spin Ni(Ⅱ), a surprisingly good structural model for [NiFe] hydrogenase [J]. J. Am. Chem. Soc.,2002,124(3):394-395.
[16]Pereira A. S., Tavares P., Moura I., et al. Mossbauer characterization of the iron-sulfur clusters in Desulfovibrio vulgaris hydrogenase [J]. J. Am. Chem. Soc.,2001,123(12):2771-2782.
[17]Bennett B., Lemon B. J., Peters J. W. Reversible carbon monoxide binding and inhibition at the active site of the Fe-only hydrogenase [J]. Biochemistry,2000,39(25):7455-7460.
[18]De Lacey A. L., Stadler C., Cavazza C., et al. FTIR Characterization of the Active Site of the Fe-hydrogenase from Desulfovibrio desulfuricans [J]. J. Am. Chem. Soc.,2000,122(45): 11232-11233.
[19]Popescu C. V., Munck E. J. Am. Chem. Soc.,1999,121:7877-7884.
[20]Lyon E. J., Georgakaki I. P., Reibenspies J. H., et al. Carbon Monoxide and Cyanide Ligands in a Classical Organometallic Complex Model for Fe-Only Hydrogenase [J]. Angew. Chem. Int. Ed., 1999,38(21):3178-3180.
[21]Schmidt M., Contakes S. M., Rauchfuss T. B. J. Am. Chem. Soc.,1999,121:9736-9737.
[22]Le Cloirec A., C. Davies S., J. Evans D., et al. A di-iron dithiolate possessing structural elements of the carbonyl/cyanide sub-site of the H-centre of Fe-only hydrogenase [J]. Chem. Commun.,1999, 0(22):2285-2286.
[23]Fan H. J., Hall M. B. A capable bridging ligand for Fe-only hydrogenase:density functional calculations of a low-energy route for heterolytic cleavage and formation of dihydrogen [J]. J. Am. Chem. Soc.,2001,123(16):3828-3829.
[24]Li H., Rauchfuss T. B. Iron carbonyl sulfides, formaldehyde, and amines condense to give the proposed azadithiolate cofactor of the Fe-only hydrogenases [J]. J. Am. Chem. Soc.,2002,124(5): 726-727.
[25]Ott S., Kritikos M., Akermark B., et al. A biomimetic pathway for hydrogen evolution from a model of the iron hydrogenase active site [J]. Angew. Chem. Int. Ed.,2004,43(8):1006-1009.
[26]Felton G. A., Vannucci A. K., Chen J., et al. Hydrogen generation from weak acids:electrochemical and computational studies of a diiron hydrogenase mimic [J]. J. Am. Chem. Soc.,2007,129(41): 12521-12530.
[27]Darchen A., Mousser H., Patin H. Two-electron transfer catalysis of carbon monoxide exchangel with a ligand in hexacarbonyldi-iron compounds [([μ-RS)2Fe2(CO)6] [J]. J. Chem. Soc, Chem. Commun.,1988,0(14):968-970.
[28]Chong D., Georgakaki I. P., Mejia-Rodriguez R., et al. Electrocatalysis of hydrogen production by active site analogues of the iron hydrogenase enzyme:structure/function relationships [J]. Dalton Trans.,2003,0(21):4158-4163.
[29]Borg S. J., Behrsing T., Best S. P., et al. Electron transfer at a dithiolate-bridged diiron assembly: electrocatalytic hydrogen evolution [J]. J. Am. Chem. Soc.,2004,126(51):16988-16999.
[30]Borg S. J., Bondin M.I., Best S. P., et al. Electrocatalytic proton reduction by dithiolate-bridged diiron carbonyl complexes:a connection to the H-cluster [J]. Biochem. Soc. Trans.,2005,33(Pt 1): 3-6.
[31]Singh P. S., Rudbeck H. C., Huang P., et al. (1,0) Mixed-valence state of a diiron complex with pertinence to the [FeFe]-hydrogenase active site:an IR, EPR, and computational study [J]. Inorg. Chem.,2009,48(23):10883-10885.
[32]Best S. P., Borg S. J., White J. M., et al. On the structure of a proposed mixed-valent analogue of the diiron subsite of [FeFe]-hydrogenase [J]. Chem. Commun.,2007,42:4348-4350.
[33]Wright R. J., Zhang W., Yang X., et al. Isolation, observation, and computational modeling of proposed intermediates in catalytic proton reductions with the hydrogenase mimic Fe2(CO)6S2C6H4 [J]. Dalton Trans.,2012,41(1):73-82.
[34]Darensbourg M. Y., Lyon E. J., Zhao X., et al. The organometallic active site of [FeFe]-hydrogenase: models and entatic states [J]. Proc. Natl. Acad. Sci. U. S. A.,2003,100(7):3683-3688.
[35]Liu T., Darensbourg M. Y. A mixed-valent, Fe(Ⅱ)Fe(Ⅰ),diiron complex reproduces the unique rotated state of the [FeFe]-hydrogenase active site [J]. J. Am. Chem. Soc.,2007,129(22): 7008-7009.
[36]Justice A. K., Rauchfuss T.B., Wilson S. R. Unsaturated, mixed-valence diiron dithiolate model for the H(ox) state of the [FeFe]-hydrogenase [J]. Angew. Chem. Int. Ed.,2007,46(32):6152-6154.
[37]Justice A. K., De Gioia L., Nilges M. J., et al. Redox and structural properties of mixed-valence models for the active site of the [FeFe]-hydrogenase:progress and challenges [J]. Inorg. Chem., 2008,47(16):7405-7414.
[38]Singleton M. L., Bhuvanesh N., Reibenspies J. H., et al. Synthetic support of de novo design: sterically bulky [FeFe]-hydrogenase models [J]. Angew. Chem. Int. Ed.,2008,47(49):9492-9495.
[39]Camara J. M., Rauchfuss T. B. Mild redox complementation enables H2 activation by [FeFe]-hydrogenase models [J]. J. Am. Chem. Soc.,2011,133(21):8098-8101.
[40]Olsen M. T., Rauchfuss T. B., Wilson S. R. Role of the azadithiolate cofactor in models for [FeFe]-hydrogenase:novel structures and catalytic implications [J]. J. Am. Chem. Soc.,2010, 132(50):17733-17740.
[41]Olsen M. T., Barton B. E., Rauchfuss T. B. Hydrogen activation by biomimetic diiron dithiolates [J]. Inorg. Chem.,2009,48(16):7507-7509.
[42]Razavet M., Borg S. J., George S. J., et al. Transient FTIR spectroelectrochemical and stopped-flow detection of a mixed valence{Fe(Ⅰ)-Fe(Ⅱ)} bridging carbonyl intermediate with structural elements and spectroscopic characteristics of the di-iron sub-site of all-iron hydrogenase [J]. Chem. Commun.,2002,7:700-701.
[43]Erdem O. F., Schwartz L., Stein M., et al. A model of the [FeFe]-hydrogenase active site with a biologically relevant azadithiolate bridge:a spectroscopic and theoretical investigation [J]. Angew. Chem. Int. Ed.,2011,50(6):1439-1443.
[44]Mealli C., Rauchfuss T. B. Models for the hydrogenases put the focus where it should be-hydrogen [J]. Angew. Chem. Int. Ed.,2007,46(47):8942-8944.
[45]Carroll M. E., Barton B. E., Rauchfuss T. B., et al. Synthetic models for the active site of the [FeFe]-hydrogenase:catalytic proton reduction and the structure of the doubly protonated intermediate [J]. J. Am. Chem. Soc.,2012,134(45):18843-18852.
[46]Silakov A., Reijerse E. J., Albracht S. P., et al. The electronic structure of the H-cluster in the [FeFe]-hydrogenase from Desulfovibrio desulfuricans:a Q-band 57Fe-ENDOR and HYSCORE study [J]. J. Am. Chem. Soc.,2007,129(37):11447-11458.
[47]Adamska A., Silakov A., Lambertz C., et al. Identification and characterization of the "super-reduced" state of the H-cluster in [FeFe]-hydrogenase:a new building block for the catalytic cycle? [J]. Angew. Chem. Int. Ed.,2012,51(46):11458-11462.
[48]Baffert C., Artero V., Fontecave M. Cobaloximes as functional models for hydrogenases.2. Proton electroreduction catalyzed by difluoroborylbis(dimethylglyoximato)cobalt(Ⅱ) complexes in organic media [J]. Inorg. Chem.,2007,46(5):1817-1824.
[49]Hu X., Brunschwig B. S., Peters J. C. Electrocatalytic hydrogen evolution at low overpotentials by cobalt macrocyclic glyoxime and tetraimine complexes [J]. J. Am. Chem. Soc.,2007,129(29): 8988-8998.
[50]Razavet M., Artero V., Fontecave M. Proton electroreduction catalyzed by cobaloximes:functional models for hydrogenases [J]. Inorg. Chem.,2005,44(13):4786-4795.
[51]Collman J. P., Cawse J. N., Kang J. W. Synthesis of sigma-bonded allenyl complexes of iridium, platinum, and cobalt [J]. Inorg. Chem.,1969,8(12):2574-2579.
[52]Schrauzer G. N., Kratel G. Organometallverbindungen von Cobaloximen und vom Vitamin B12 [J]. Angew. Chem.,1965,77(3):130-130.
[53]Jacques P. A., Artero V., Pecaut J., et al. Cobalt and nickel diimine-dioxime complexes as molecular electrocatalysts for hydrogen evolution with low overvoltages [J]. Proc. Natl. Acad. Sci. U. S. A., 2009,106(49):20627-20632.
[54]Curtis C. J., Miedaner A., Ellis W. W., et al. Measurement of the hydride donor abilities of [HM(diphosphine)2]+complexes (M=Ni, Pt) by heterolytic activation of hydrogen [J]. J. Am. Chem. Soc.,2002,124(9):1918-1925.
[55]Curtis C. J., Miedaner A., Ciancanelli R., et al. [Ni(Et2PCH2NMeCH2PEt2)2]2+ as a functional model for hydrogenases [J]. Inorg. Chem.,2003,42(1):216-227.
[56]Wilson A. D., Newell R. H., Mcnevin M. J., et al. Hydrogen oxidation and production using nickel-based molecular catalysts with positioned proton relays [J]. J. Am. Chem. Soc.,2006,128(1): 358-366.
[57]Wilson A. D., Fraze K., Twamley B., et al. The role of the second coordination sphere of [Ni(PCy2NBz2)2](BF4)2 in reversible carbon monoxide binding [J]. J. Am. Chem. Soc.,2008,130(3): 1061-1068.
[58]Yang J. Y., Chen S., Dougherty W. G., et al. Hydrogen oxidation catalysis by a nickel diphosphine complex with pendant tert-butyl amines [J]. Chem. Commun.,2010,46(45):8618-8620.
[59]Galan B. R., Schoffel J., Linehan J. C., et al. Electrocatalytic oxidation of formate by [Ni(P(R)2N(R')2)2(CH3CN)]2+ complexes [J]. J. Am. Chem. Soc.,2011,133(32):12767-12779.
[60]Kilgore U. J., Stewart M. P., Helm M. L., et al. Studies of a series of [Ni(P(R)2N(Ph)2)2(CH3CN)]2+ complexes as electrocatalysts for H2 production:substituent variation at the phosphorus atom of the P2N2 ligand [J]. Inorg. Chem.,2011,50(21):10908-10918.
[61]Liu T., Chen S., O'hagan M. J., et al. Synthesis, characterization, and reactivity of Fe complexes containing cyclic diazadiphosphine ligands:the role of the pendant base in heterolytic cleavage of H2 [J]. J. Am. Chem. Soc.,2012,134(14):6257-6272.
[62]O'hagan M., Ho M. H., Yang J. Y., et al. Proton delivery and removal in [Ni(P(R)2N(R')2)2]2+ hydrogen production and oxidation catalysts [J]. J. Am. Chem. Soc.,2012,134(47):19409-19424.
[63]Pool D. H., Stewart M. P., O'hagan M., et al. Acidic ionic liquid/water solution as both medium and proton source for electrocatalytic H2 evolution by [Ni(P2N2)2]2+ complexes [J]. Proc. Natl. Acad. Sci. U. S. A.,2012,109(39):15634-15639.
[64]Raugei S., Chen S., Ho M. H., et al. The role of pendant amines in the breaking and forming of molecular hydrogen catalyzed by nickel complexes [J]. Chemistry,2012,18(21):6493-6506.
[65]Shaw W. J., Helm M. L., Dubois D. L. A modular, energy-based approach to the development of nickel containing molecular electrocatalysts for hydrogen production and oxidation [J]. Biochim. Biophys. Acta.,2013, doi:10.1016/j.bbabio.2013.01.003.
[66]Helm M. L., Stewart M. P., Bullock R. M., et al. A synthetic nickel electrocatalyst with a turnover frequency above 100,000 s-1 for H2 production [J]. Science,2011,333(6044):863-866.
[67]Wang M., Chen L., Sun L. Recent progress in electrochemical hydrogen production with earth-abundant metal complexes as catalysts [J]. Energy Environ. Sci,2012,5(5):6763-6778.
[68]Karunadasa H. I., Chang C. J., Long J. R. A molecular molybdenum-oxo catalyst for generating hydrogen from water [J]. Nature,2010,464(7293):1329-1333.
[69]Karunadasa H. I., Montalvo E., Sun Y., et al. A molecular MoS(2) edge site mimic for catalytic hydrogen generation [J]. Science,2012,335(6069):698-702.
[70]Sun Y., Bigi J. P., Piro N. A., et al. Molecular cobalt pentapyridine catalysts for generating hydrogen from water [J]. J. Am. Chem. Soc.,2011,133(24):9212-9215.
[71]Capon J.-F., Gloaguen F., Petillon F. Y., et al. Electron and proton transfers at diiron dithiolate sites relevant to the catalysis of proton reduction by the [FeFe]-hydrogenases [J]. Coord. Chem. Rev, 2009,253(9-10):1476-1494.
[72]Barton B. E., Rauchfuss T. B. Terminal hydride in [FeFe]-hydrogenase model has lower potential for H2 production than the isomeric bridging hydride [J]. Inorg. Chem.,2008,47(7):2261-2263.
[73]Ezzaher S., Capon J.-F., Gloaguen F., et al. Electron-Transfer-Catalyzed rearrangement of unsymmetrically substituted diiron dithiolate complexes related to the active site of the [FeFe]-Hydrogenases [J]. Inorg. Chem.,2007,46(23):9863-9872.
[74]Barton B. E., Olsen M. T., Rauchfuss T. B. Aza- and oxadithiolates are probable proton relays in functional models for the [FeFe]-hydrogenases [J]. J. Am. Chem. Soc.,2008,130(50): 16834-16835.
[75]Silakov A., Wenk B., Reijerse E., et al. 14N-HYSCORE investigation of the H-cluster of [FeFe]-hydrogenase:evidence for a nitrogen in the dithiol bridge [J]. Phys. Chem. Chem. Phys.,2009, 11(31):6592-6599.
[76]Erdem F., Schwartz L., Stein M., et al. A model of the [FeFe]-hydrogenase active site with a biologically relevant azadithiolate bridge:a spectroscopic and theoretical investigation [J]. Angew. Chem. Int. Ed.,2011,50(6):1439-1443.
[77]Thomas C. M., Liu T., Hall M. B., et al. Series of mixed valent Fe(Ⅱ)Fe(Ⅰ) complexes that model the Hox state of [FeFe]-hydrogenase:redox properties, density-functional theory investigation, and reactivities with extrinsic CO [J]. Inorg. Chem.,2008,47(15):7009-7024.
[78]Tard C., Liu X., Ibrahim S. K., et al. Synthesis of the H-cluster framework of iron-only hydrogenase [J]. Nature,2005,433(7026):610-613.
[79]Liu Y.-C., Lee C.-H., Lee G.-H., et al. Influence of a Redox-Active Phosphane Ligand on the Oxidations of a Diiron Core Related to the Active Site of Fe-Only Hydrogenase [J]. Eur. J. Inorg. Chem.,2011,2011 (7):1155-1162.
[80]Zeng X., Li Z., Xiao Z., et al. Using pendant ferrocenyl group(s) as an intramolecular standard to probe the reduction of diiron hexacarbonyl model complexes for the sub-unit of [FeFe]-hydrogenase [J]. ElectroChem. Commun.,2010,12(3):342-345.
[81]Si Y., Charreteur K., Capon J.-F., et al. Non-innocent bma ligand in a dissymetrically disubstituted diiron dithiolate related to the active site of the [FeFe]-hydrogenases [J]. J. Inorg. Biochem.,2010, 104(10):1038-1042.
[82]Camara J. M., Rauchfuss T. B. Combining acid-base, redox and substrate binding functionalities to give a complete model for the [FeFe]-hydrogenase [J]. Nat. Chem.,2012,4(1):26-30.
[83]Le Goff A., Artero V., Jousselme B., et al. From hydrogenases to noble metal-free catalytic nanomaterials for H2 production and uptake [J]. Science,2009,326(5958):1384-1387.
[84]Andreiadis E. S., Jacques P. A., Tran P. D., et al. Molecular engineering of a cobalt-based electrocatalytic nanomaterial for H2 evolution under fully aqueous conditions [J]. Nat. Chem.,2013, 5(1):48-53.
[85]Tran P. D., Le Goff A., Heidkamp J., et al. Noncovalent modification of carbon nanotubes with pyrene-functionalized nickel complexes:carbon monoxide tolerant catalysts for hydrogen evolution and uptake [J]. Angew. Chem. Int. Ed.,2011,50(6):1371-1374.
[86]Fihri A., Artero V., Razavet M., et al. Cobaloxime-based photocatalytic devices for hydrogen production [J]. Angew. Chem. Int. Ed.,2008,47(3):564-567.
[87]Li X., Wang M., Zhang S., et al. Noncovalent Assembly of a Metalloporphyrin and an Iron Hydrogenase Active-Site Model:Photo-Induced Electron Transfer and Hydrogen Generation [J]. J. Phys. Chem. B,2008,112(27):8198-8202
[88]Zhang P., Wang M., Li C., et al. Photochemical H2 production with noble-metal-free molecular devices comprising a porphyrin photosensitizer and a cobaloxime catalyst [J]. Chem. Commun., 2010,46(46):8806-8808.
[89]Duan L., Bozoglian F., Mandal S., et al. A molecular ruthenium catalyst with water-oxidation activity comparable to that of photosystem I [J]. Nat. Chem.,2011,4(5):418-423.
[90]Kanan M. W., Nocera D. G. In situ formation of an oxygen-evolving catalyst in neutral water containing phosphate and Co2+[J]. Science,2008,321(5892):1072-1075.
[91]Conway B. E., Bai L. H2 evolution kinetics at high activity Ni-Mo-Cd electrocoated cathodes and its relation to potential dependence of sorption of H [J]. Int. J. Hydrogen Energy,1986,11(8):533-540.
[92]Reece S. Y., Hamel J. A., Sung K., et al. Wireless solar water splitting using silicon-based semiconductors and earth-abundant catalysts [J]. Science,2011,334(6056):645-648.
[93]Diallo A. K., Daran J. C., Varret F., et al. How do redox groups behave around a rigid molecular platform? Hexa(ferrocenylethynyl)benzenes and their "electrostatic" redox chemistry [J]. Angew. Chem. Int. Ed.,2009,48(17):3141-3145.
[94]Astruc D. Ferrocenyl dendrimers:multi-electron redox reagents and their applications [J]. New J. Chem.,2011,35(4):764-772.
[95]Zhao Q., Harris T. D., Betley T. A. [((H)L)2Fe6(NCMe)m]n+(m=0,2,4,6; n=-1,0,1,2,3,4,6): an electron-transfer series featuring octahedral Fe6 clusters supported by a hexaamide ligand platform [J]. J. Am. Chem. Soc.,2011,133(21):8293-8306.
[96]Felton G. A. N., Mebi C. A., Petro B. J., et al. Review of electrochemical studies of complexes containing the Fe2S2 core characteristic of [FeFe]-hydrogenases including catalysis by these complexes of the reduction of acids to form dihydrogen [J]. J. Organomet. Chem.,2009,694(17): 2681-2699.
[97]Maiolo F., Testaferri L., Tiecco M., et al. Fragmentation of aryl alkyl sulfides. A simple, one-pot synthesis of polymercaptobenzenes from polychlorobenzenes [J]. J. Org. Chem.,1981,46(15): 3070-3073.
[98]Yip H. K., Schier A., Riede J., et al. Benzenehexathiol as a template rim for a golden wheel: synthesis and structure of [{CSAu(PPh3)}6] [J]. J. Chem. Soc., Dalton Trans.,1994,0(15): 2333-2334
[99]Capon J. F., Gloaguen F., Schollhammer P., et al. Di-iron aza diphosphido complexes:mimics for the active site of Fe-only hydrogenase, and effects of changing the coordinating atoms of the bridging ligand in [Fe2[μ-(ECH2)2NR](CO)6] [J]. J. Electroanal. Chem.,2004,566:241-247.
[100]Gloaguen F., Morvan D., Capon J. F., et al. Bioactive capsular polysaccharide from the thermophilic cyanophyte/cyanobacterium mastigocladus laminosus-cytotoxic properties [J]. J. Electroanal. Chem.,2007,603:15-20.
[101]Chong D., Georgakaki I. P., Mejia-Rodriguez R., et al. Electrocatalysis of hydrogen production by active site analogues of the iron hydrogenase enzyme:structure/function relationships [J]. Dalton Trans.,2003,4158-4163.
[102]Lyon E. J., Georgakaki I. P., Reibenspies J. H., et al. Carbon monoxide and cyanide ligands in a classical organometallic complex model for Fe-only hydrogenase [J]. Angew. Chem. Int. Ed.,1999, 38:3178-3180.
[103]Orain P.-Y., Capon J.-F., Gloaguen F., et al. Tuning of electron transfer in diiron azo-bridged complexes relevant to hydrogenases [J]. Int. J. Hydrogen. Energy.,2010,35(19):10797-10802.
[104]Chen J., Vannucci A. K., Mebi C. A., et al. Synthesis of diiron hydrogenase mimics bearing hydroquinone and related ligands. electrochemical and computational studies of the mechanism of hydrogen production and the role of O-H-S hydrogen bonding [J]. Organometallics,2010,29(21): 5330-5340.
[105]Diallo A. K., Daran J.-C., Varret F., et al. How do redox groups behave around a rigid molecular platform? hexa(ferrocenylethynyl)benzenes and their "electrostatic" redox chemistry [J]. Angew. Chem. Int. Ed.,2009,48(17):3141-3145.
[106]Zhao Q., Harris T. D., Betley T. A. [(HL)2Fe6(NCMe)m]n+(m= 0,2,4,6; n=-1,0,1,2,3,4,6): An electron-transfer series featuring octahedral Fe6 clusters supported by a hexaamide ligand platform [J]. J. Am. Chem. Soc.,2011,133(21):8293-8306.
[107]Li P., Wang M., Pan J., et al. [FeFe]-Hydrogenase active site models with relatively low reduction potentials:Diiron dithiolate complexes containing rigid bridges [J]. J. Inorg. Biochem.,2008, 102(4):952-959.
[108]Boelens M., De Kimpe N., Keppens M., et al. Proof of the stereochemistry of cis-2,5-dibromocyclopentanone [J]. J. Org. Chem.,1994,59(15):4170-4171.
[109]Wright J. A., Pickett C. J. Protonation of a subsite analogue of [FeFe]-hydrogenase:mechanism of a deceptively simple reaction revealed by time-resolved IR spectroscopy [J]. Chem. Commun., 2009,0(38):5719-5721.
[110]Song L.-C., Li C.-G., Gao J., et al. Synthesis, Structure, and Electrocatalysis of Diiron C-Functionalized Propanedithiolate (PDT) Complexes Related to the Active Site of [FeFe]-Hydrogenases [J]. Inorg. Chem.,2008,47(11):4545-4553.
[111]Chen X.-D., Du M., He F., et al. Ligand behavior of 2,6-pyridinediylbis(2-pyridinyl)methanone in solvent-controlled formation of iron(Ⅲ) complexes:A novel asymmetric quasi-linear trinuclear core containing an eight-coordinate iron center [J]. Polyhedron,2005,24(9):1047-1053.
[112]Cranswick M. A., Gruhn N. E., Enemark J. H., et al. Electronic structure of the d bent-metallocene Cp(2)VCl(2):A photoelectron and density functional study [J]. J. Organomet. Chem.,2008, 693(8-9):1621-1627.
[113]Jeffery J. C., Odell B., Stevens N., et al. Self assembly of a novel water soluble iron macrocyclic phosphine complex from tetrakis(hydroxymethyl)phosphonium sulfate and iron ammonium sulfate: single crystal X-ray structure of the complex [Fe(HO){RP(CHN(CHPR)CH)PR}]SO4·4H2O (R= CH2OH) [J]. Chem. Commun.,2000,0(1):101-102.
[114]Bakac A., Brynildson M. E., Espenson J. H. Characterization of the structure, properties, and reactivity of a cobalt(Ⅱ) macrocyclic complex [J]. Inorg. Chem.,1986,25(23):4108-4114.
[115]Merki D., Vrubel H., Rovelli L., et al. Fe, Co, and Ni ions promote the catalytic activity of amorphous molybdenum sulfide films for hydrogen evolution [J]. Chem. Sci,2012,3(8): 2515-2525.
[116]Collin J. P., Jouaiti A., Sauvage J. P. Electrocatalytic properties of (tetraazacyclotetradecane)nickel2+ and Ni2(biscyclam)4+ with respect to carbon dioxide and water reduction [J]. Inorg. Chem.,1988,27(11):1986-1990.
[117]Bernhardt P. V., Jones L. A. Electrochemistry of Macrocyclic Cobalt(Ⅲ/Ⅱ) Hexaamines: Electrocatalytic Hydrogen Evolution in Aqueous Solution [J]. Inorg. Chem.,1999,38(22): 5086-5090.
[118]Singh W. M., Baine T., Kudo S., et al. Electrocatalytic and photocatalytic hydrogen production in aqueous solution by a molecular cobalt complex [J]. Angew. Chem. Int. Ed.,2012,51(24): 5941-5944.
[119]Houlding V., Geiger T., KoLle U., et al. Electrochemical and photochemical investigations of two novel electron relays for hydrogen generation from water [J]. J. Chem. Soc., Chem. Commun.,1982, 12):681-683.
[120]Koelle U., Paul S. Electrochemical reduction of protonated cyclopentadienylcobalt phosphine complexes [J]. Inorg. Chem.,1986,25(16):2689-2694.
[121]Stubbert B. D., Peters J. C., Gray H. B. Rapid water reduction to H2 catalyzed by a cobalt bis(iminopyridine) complex [J]. J. Am. Chem. Soc.,2011,133(45):18070-18073.
[122]Anxolabehere-Mallart E., Costentin C., Fournier M., et al. Boron-capped tris(glyoximato) cobalt clathrochelate as a precursor for the electrodeposition of nanoparticles catalyzing H2 evolution in water [J]. J. Am. Chem. Soc.,2012,134(14):6104-6107.
[123]Artero V., Fontecave M. Solar fuels generation and molecular systems:is it homogeneous or heterogeneous catalysis? [J]. Chem. Soc. Rev.,2013,42(6):2338-2356.
[124]Muresan N. M., Willkomm J., Mersch D., et al. Immobilization of a molecular cobaloxime catalyst for hydrogen evolution on a mesoporous metal oxide electrode [J]. Angew. Chem. Int. Ed.,2012, 51(51):12749-12753.
[125]Kellett R. M., Spiro T. G. Cobalt porphyrin electrode films as hydrogen catalysts [J]. Inorg. Chem., 1985,24:2378-2382.
[126]Bujno K., Bilewicz R., Siegfried L., et al. Effects of ligand structure on the adsorption of nickel tetraazamacrocyclic complexes and electrocatalytic CO2 reduction [J]. Electroanal. Chem.,1998, 445:47-53.
[127]Schneider J., Jia H., Kobiro K., et al. Nickel(Ⅱ) macrocycles:highly efficient electrocatalysts for the selective reduction of CO2 to CO [J]. Energy Environ. Sci.,2012,5(11):9502-9510.