Photochromic behavior of a new polyoxomolybdate/alkylamine composite in solid state

A new polyoxomolybdate/alkylamine composite (C3N2H5)6[As4Mo8O33]·4H2O [1] was successfully synthesized by controlling the reaction parameters in the conventional aqueous solution. Compound 1 was well characterized by single-crystal X-ray diffraction, FTIR, XPRD analysis, TGA and elemental analyses. It was found that compound 1 exhibited intriguing photochromic behavior along with interesting thermochromic property as the color of 1 turns from white to blue-mazarine with rise in temperature. Furthermore, compound 1 features distinct photochromic behavior in the solid state. This new arsenomolybdate/alkylamine composite can change color from white to pale blue upon irradiation by a xenon lamp (full wave-band, P = 300 W). The photochromism of 1 involves the reduction of Mo6+ to Mo5+, indicating crucial role in proton transfer from the imidazole cations toward the polyanion.