Water‐Resistant and Transparent Plastic Films from Functionalizable Organic Polymers: Coordination Polymers as Templates for Solid‐State [2+2]‐Photopolymerization

An organic polymer containing cyclobutanes and amides as backbones and pyridyl groups as sidearms was synthesized by single‐crystal‐to‐single‐crystal (SCSC) [2+2]‐photopolymerization in the coordination polymers (CPs) of diene. The diene molecule was photo‐inactive in its crystals and formed a triply intertwined 1D‐helical CP with Cd(NO3)2 and Cu(NO3)2 salts. The 1D‐CP was transformed into a coordination polymer of organic polymers containing threefold interpenetrated 3D‐networks of CdSO4 topology through a [2+2]‐reaction in SCSC manner upon irradiation. The organic polymer was separated from its CPs and found to have an unusually high degree of polymerization for this type of reaction. Furthermore, the organic polymer was amenable for N‐alkylation reactions such as methylation, propylation, and decylation. The formate salts of the organic polymer and the methylated polymer were shown to form plastic films with a combination of properties such as high transparency, tensile strengths, gas permeability, thermal stability, water‐resistance, and resistance to other organic solvents. The methylated polymer was also able to capture chromate ions and anionic dyes from aqueous solutions. Making a film: Single‐crystal‐to‐single‐crystal [2+2]‐photopolymerization in coordination polymers of a diene results in an organic polymer that is amenable for functionalization. Such functionalizations result in a change of properties such as formation of plastic films, high transparency, tensile strengths, gas permeability, thermal stability, and water‐resistant nature, as well as absorption of chromate ions and anionic dyes from aqueous solutions.