Two photochromic hybrid materials assembled from naphthalene diimide as photocatalysts for the degradation of carcinogenic dye basic red 9 under visible light

Abstract

• Two electron-transfer hybrid compounds based on electron-deficient naphthalene diimide and polyoxometalate were synthesized and characterized. • Complexes 1 and 2 exhibit the eye-detectable photochromic phenomenon. • Complexes 1 and 2 show good photocatalytic activity for degradation of carcinogenic dye BR9. Naphthalene diimide (NDI) derivatives and polyoxometalates (POMs) are two kinds of functional moieties with very different properties for applications in different fields. Two rare multifunctional inorganic-organic hybrid crystalline materials based on NDI and POM, have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analyses, and thermogravimetric analysis. These compounds show fast responsive reversible photochromic behaviors (within five minutes) under UV–vis light irradiation, which arise from the photoinduced electron transfer production of organic radicals rather than photoinduced isomerization or photolysis. Furthermore, due to presence the redox-active NDI and POMs, these unique hybrid materials are good heterogeneous photocatalyst for the degradation of carcinogenic organic dye basic red 9 (BR9) with a degradation rate of more than 86% within 120 min in the presence of H 2 O 2 under visible light irradiation. This work will provide a new perspective to explore multifunctional hybrid materials with useful photochromic and photocatalytic properties.