Modulating the polyoxometalate-based inorganic–organic hybrids from simple chains to complicated frameworks via changing POM clusters†
Investigation into a hydrothermal reaction system with a copper salt, 1-(imidazo-1-ly)-4-(1,2,4-triazol-1-ylmethyl)benzene) (itb) ligand and three types of polyoxometalates (POMs) led to the preparation of three new coordination polymers, [Cu2(itb)4(H4P2W18O62)]·H2O (1), [Cu(itb)4(HPW12O40)]·4H2O (2) and [Cu2(itb)2(Mo8O26)]·6H2O (3). The three coordination polymers were characterized by elemental analyses, single-crystal X-ray diffraction, powder X-ray diffraction, XPS and IR spectra. Structural analyses show that with modulating the type of POM anions from [Mo8O26]4− and [PW12O40]3− to [P2W18O62]6−, the three coordination polymers possess distinct structural motifs: simple one-dimensional (1D) chain (1), 1D + 1D → 2D interdigitated architectures (2) and complicated 3D frameworks consisting of both meso-helixes and left/right-helixes (3). The distinct structural features of the three coordination polymers suggest that the POM anions should play a significant role in the process of assembly. The electrocatalytic and luminescent properties for coordination polymers 1–3 have been investigated.