A Multifunctional Coordination Polymer for Photochromic Films, Smart Windows, Inkless and Erasable Prints and Anti-Counterfeiting

Herein, a multifunctional two-dimensional viologen-based coordination polymer [Zn (CV)0.5 center dot(BDC)0.5 center dot Br] (1) (CV = N,N '-4,4'-bipyridiniodipropionate, BDC2-= terephthalic acid) has been constructed. It exhibits rapid light response ability with color changing from colorless to blue. Furthermore, photochromic gelatin films containing compound 1 were prepared. The addition of gelatin endows the films with high transparency and improves the photochromic properties. It is expected that the films have the advantages of fast photochromism, easy operation, and recyclability. Therefore, smart windows with energy saving and decorative properties are made from this film. Additionally, the properties of fast discoloration make compound 1 suitable for inkless and erasable prints and anti-counterfeiting applications.