Three Transition-Metal Substituted Polyoxotungstates Containing Keggin Fragments: From Trimer to One-Dimensional Chain to Two-Dimensional Sheet
详细信息 查看全文
- 作者：Lijuan Chen ; Dongying Shi ; Junwei Zhao ; Yulong Wang ; Pengtao Ma ; Jingping Wang ; Jingyang Niu
- 刊名：Crystal Growth & Design
- 出版年：2011
- 出版时间：May 4, 2011
- 年：2011
- 卷：11
- 期：5
- 页码：1913-1923
- 全文大小：1149K
- 年卷期：v.11,no.5(May 4, 2011)
- ISSN：1528-7505
文摘
Three novel transition-metal substituted polyoxotungstates based on Keggin fragments, Cs3K3[Co(H2O)6]2[Co(H2O)3(伪-GeW11CoO38)3]路30H2O (1), K18{[Mn(H2O)3]2[Mn(H2O)2][(B-尾-SiW9O33(OH))Mn3(H2O)(B-尾-SiW8O30(OH))]2}路16H2O (2), and K8[Cd(H2O)3]2[Cd4(H2O)2(B-伪-SiW9O34)2]路20H2O (3), have been synthesized by reaction of dilacunary Keggin precursors K8[纬-GeW10O36]路6H2O/K8[纬-SiW10O36]路12H2O with transition-metal salts at ambient temperature and characterized by inductively coupled plasma (ICP) analyses, IR spectra, UV spectra, and single-crystal X-ray diffraction. The polyoxoanion of 1 is a novel trimer constructed from three mono-CoII substituted Keggin fragments [伪-GeW11CoO38]4鈭?/sup> linked by six W鈭扥鈭扖o/W bridges and a capping [Co(H2O)3]2+ bridge. 2 displays the one-dimensional chain built by tetrameric {[Mn(H2O)3]2[Mn(H2O)2][(B-尾-SiW9O33(OH))Mn3(H2O)(B-尾-SiW8O30(OH))]2}18鈭?/sup> units, which is the first one-dimensional silicotungstate containing asymmetric sandwich-type moieties constructed from [B-尾-SiW9O34]10鈭?/sup> and [B-尾-SiW8O31]10鈭?/sup> fragments. 3 utilizes the two-dimensional sheet established by tetra-CdII substituted sandwich-type [Cd4(H2O)2(B-伪-SiW9O34)2]12鈭?/sup> units and [Cd(H2O)3]2+ linkers, representing the first two-dimensional (3,6)-topological network with a Schl盲fli symbol of 364653 built by sandwich-type Keggin units in polyoxometalate chemistry. Magnetic susceptibility measurements indicate antiferromagnetic exchange interactions within CoII ions in 1 and within MnII ions in 2. The best least-squares fitting values for 2 are J = 鈭?.16 cm鈭? and g = 2.13 based on the isostropic spin model. Furthermore, the room-temperature solid-state photoluminescence of 3 displays two emission bands, which are derived from O 鈫?Cd ligand-to-metal charge transfer transitions and O 鈫?W ligand-to-metal charge transfer transitions, respectively.