American Chemical Society
ic901330y_si_002.cif (264.37 kB)

Rare Sandwich-Type Polyoxomolybdates Constructed from Di-/Tetra-Nuclear Transition-Metal Clusters and Trivacant Keggin Germanomolybdate Fragments

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posted on 2009-10-19, 00:00 authored by Suzhi Li, Junwei Zhao, Pengtao Ma, Juan Du, Jingyang Niu, Jingping Wang
Two types of rare sandwich-type germanomolybdates [Na12(H2O)36][Cu2(β-Y-GeMo9O33)2]·3H2O (1), [N(CH3)4]4 [Na6(H2O)24][Cr2(β-Y-GeMo9O33)2]·7H2O (2), and [Na11(H2O)25]H[M4(H2O)2(α-B-GeMo9O34)2]·6H2O (M = NiII for 3, M = MnII for 4 and M = CoII for 5) have been synthesized and characterized by elemental analyses, ICP spectra, IR spectroscopy, UV spectroscopy, thermogravimetry (TG) analyses (for 13), X-ray photoelectron spectroscopy (XPS) (for 1 and 3), X-ray powder diffraction (XRPD) (for 1 and 3) and single-crystal X-ray diffraction. To our knowledge, 15 represent the first sandwich-type germanomolybdates containing both {β-Y-GeMo9O33}/{α-B-GeMo9O34} fragments and transition-metal clusters. Interestingly, 1 and 2 display the rare dinuclear transition-metal substituted sandwich-type structures with unusual trivacant {β-Y-GeMo9O33} germanomolybdate units whereas 35 exhibit the first tetranuclear transition-metal substituted sandwich-type structures with familiar trivacant {α-B-GeMo9O34} germanomolybdate units. Surface photovoltage spectroscopy (SPS) and electric field induced surface photovoltage spectroscopy (EFISPS) measurements reveal that 1 and 3 bear the behavior of the n-type semiconductor. Magnetic measurements indicate 1 and 3 demonstrate antiferromagnetic exchange interactions and ferromagnetic exchange interactions, respectively.