Photo-, Thermo-, Electrochromic, Erasable Inkless Printing, Ions Detection, and UV Detector Properties of Viologen Compounds Based on Homomolybdate/Keggin POMs.

Three POMs-based viologen compounds with different structures were successfully constructed under solvothermal and hydrothermal conditions, [Cu(1,4-cby)(HO)(β-MoO)]·CHNO·3HO (), [H(1,4-cby)]·(β-MoO) () (1,4-cby·Cl = 1-(4-carboxybenzyl)-4,4'-bipyridine chloride), [H(1,4-cbyy)]·(SiMoO) () (1,4-cbyy·Cl = 1-(4-cyanobenzyl)-4,4'-bipyridine chloride). Compound is a structure with the number "eight-like" metal-organic chain with Cu as the nodes, and compounds and are fascinating structures connected by hydrogen bonding interactions. More importantly, compounds exhibit a good response to both light and electricity and the thermal response of compound was also studied. The reasons for the response of compounds - to external stimuli were analyzed through methods such as UV-Vis, EPR, and XPS. In addition, the transient photocurrent response results of compounds - are the same as those obtained from kinetic calculations. Meanwhile, the coated filter paper based on compound has been successfully applied in erasable inkless printing and anti-counterfeiting, the test paper of can also detect metal ions, and the films based on compounds - are a flexible and portable ultraviolet (UV) detector.