Reversible single-crystal-to-single-crystal photoisomerization of a silver(I) macropolyhedral borane

We report a new family of photoactive molecular compounds for which reversible solid state transformations and linkage isomerism have been observed using in situ X-ray diffraction. The interaction of tris(triphenylphosphine)silver(I) with eicosaborate [B20H18](2-) afforded a binuclear complex with a bridging boron cluster that underwent a series of isomerization transformations occurring in a single-crystal-to-single-crystal manner without crystal degradation and obeying the criteria for an effective molecular switch.