A novel photochromic metal–organic framework with good anion and amine sensing

A novel metal-organic hybrid photochromic compound [Zn (CV) (L2)]·2H2O (1) (CV = N,N'-4,4'-bipyridiniodipropionate, H2L2 = isophthalic acid) has been synthesized solvothermally. Compound 1 features a two-dimensional (2D) framework structure, exhibiting photochromic properties under sunlight and UV irradiation with an obvious color change from colorless to dark blue. Meanwhile, the luminescence properties of 1 were investigated, and the results suggested that 1 has good properties of detecting dichromate ions. Furthermore, compound 1 shows different color changes when exposed to different alkyl-amines, and 1 can also be deposited into paper to use as portable test strips. This work can be applied to practical applications as a multifunctional detector against light and chemicals.