Cyclopolymerization Of 1,2-Dicarbodiimides

Intramolecular cyclopolymerizations have been achieved by the polymerization of 1,2-dicarbodiimides using a CpTi-Cl2OCH2CF3 catalyst. Here, we have extended the living polymerization approach of monocarbodiimide polymerization using Ti(IV)-based initiators into dicarbodiimide polymerization. Polymerization occurs via an alternating intra-intermolecular cyclization and monomer addition to form polymers with this new architecture. Cyclopolymerization was carried out by tethering two neighboring carbodiimide functional groups with two- and three-carbon linkers in order to favor the intramolecular cyclization within the backbone. Linkers greater than three carbons lead to cross-linked networks. We believe these cyclopolymers contain both five- and seven-membered rings. Using enantiomerically pure monomers, e.g., trans-1,2 cyclohexyl linkers, cyclopolycarbodiimides that possess chiral conformations can be synthesized. With imparting cyclic structures along the polymer backbone, these cyclopolymers possess significant contrast compared to their acyclic polymers of carbodiimides.