A novel approach to achieve molecular switching in solid-state driving by thermal treatment: A photochromic zinc-coordination polymer

The molecular switching of complexes based on diarylethenes in a solid-state is their most frequently studied property. This switching becomes possible when the active carbon atoms acquire a suitable interatomic separation in the molecule. Even if the structural analysis may suggest conditions disfavouring the occurrence of such switching, it may still be enabled by post-synthetic modification of the sample, like dehydration. In the present study, a novel one-dimensional coordination polymer with composition {[Zn(μ3-HA)(H2O)3]·H2O}n (I) was prepared and characterized. In its solid state, however, its thiophene rings were arranged in the non-switchable conformation yielding a C···C separation 4.148(6) Å between the active carbon atoms. After fully dehydrating the sample, this interatomic separation decreased to 3.814 Å, making it susceptible to photochromism by UV radiation.