Dimeric Organic–Inorganic Hybrid Zr-Substituted Antimonotungstate-Featured Photochromic Responses

Photochromic materials are increasingly attracting attention for their potential applications in smart devices. Here, a novel organic–inorganic hybrid Zr-containing polyoxometalate [H2N(CH3)2]10H8[Zr(DL-tart)2(SbW17ZrO58)2]·36H2O (DL-tartH4 = dl-Tartaric Acid) (1) was synthesized. The dimeric polyanion of 1 contains two Dawson-like {SbW17ZrO58}7– subunits bridged by one {Zr(DL-tart)2}4– connector. Interestingly, compound 1 exhibits a rapid photochromic response with a half-life (t1/2) of 6.62 s, good reversibility, and an easy fading process in an air environment. Notably, compound 1 also retains its photochromic behavior upon exposure to visible light irradiation.