Self-assembly of supramolecular networks based on biphosphopentamolybdate and copper—organic units

摘要

Two polyoxometalates (POMs)-based hybrid supramolecular materials have been synthesized based on biphosphopentamolybdate and copper-organic units under hydrothermal conditions, namely, [(HP04)_2Mo_5O_(15)][Cu~I(4,4'-bipy)]2[Cu~(II)(en)2]6H_2O (1) and [(HPO_4)_2Mo_5O_(15)][Cu,(4,4'-bipy)]4.6H_2O (2) (en = ethyle-nediamine and 4,4'-bipy = 4,4'-bipyridine). Their crystal structures have been characterized by elemental analysis, IR, thermal gravimetric analysis (TGA), and single-crystal X-ray diffraction analysis. The novel 2D supramolecular sheet is formed via weak copper-oxygen interaction and hydrogen bonding in 1. The fascinating structural feature of 2 is that the biphosphopentamolybdate polyanion acts as a pillar to link Cu~I centers and shows six-connected nodes. The electrochemical behaviors of hybrid materials have been studied in detail.