Photo-responsive metal-organic gels of rigid phenylene-1,3-di-substituted angular dienes with metal halides: gel-to-gel transformations triggered by [2 + 2] polymerization.

Herein, the first report on gel-to-gel transformations [2 + 2] photopolymerization in MOGs of metal halides and rigid dienes is presented. The MOGs and their xerogels show exceptional ability to undergo [2 + 2] polymerisation upon UV irradiation. Gel-to-gel transformations are very rare as the post-modification of gelators weakens the gel and transforms it to a sol. Such transformations change the molecular assemblies into gels with altered mechanical and chemical properties. These phenomena pave the way to synthesize new MOGs with improved rigidity that cannot be synthesized otherwise.