Synthesis, Crystal Structure, and Properties of Two Sandwich-type Tungstovanadates
writer：Bao Li, Yi Yan, Fengyan Li, Lin Xu, Lihua Bi, Lixin Wu*
keywords：Tungstovanadates, Sandwich-type, Transition metals, Crystal structure
source：期刊
specific source：Inorganica Chimica Acta 2009, 362, 2796-2801.
Issue time：2009年
Two dimeric tungstovanadates of the form [M4(H2O)2(VW9O34)2]10 (M = MnII, CoII) were synthesized and characterized by elemental analysis, thermogravimetric analysis and infrared spectroscopy. X-ray single crystal analysis revealed that the two polyanion clusters with isomorphic structure consist of two lacunary [VW9O34]9 Keggin moieties linked by four MnII or CoII ions, forming a sandwich-type structure. The temperature-dependent magnetic susceptibility measurements showed a dominant antiferromagnetic interaction in complex 1, while ferromagnetic interactions were found in complex 2. The electrochemical behaviors of complexes 1 and 2 were investigated in buffer solution at pH 4.8. Surface photovoltage spectroscopy (SPS) and electric field-induced SPS (EFISPS) revealed that complex 1 bears the behavior of an n-type semiconductor, while complex 2 shows no obvious signal.