Modulating the polyoxometalate-based inorganic–organic hybrids from simple chains to complicated frameworks via changing POM clusters

Abstract

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.