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(μ(3)-HA)(H2O)(3)].H2O}(n) (I) was prepared and characterized.
In its solid state, however, its thiophene rings were arranged in the nonswitchable 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.