Bicyclic Guanidinium Tetraphenylborate: A Photobase Generator and A Photocatalyst for Living Anionic Ring-Opening Polymerization and Cross-Linking of Polymeric Materials Containing Ester and Hydroxy Groups

1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) with pKa of 26.03 in acetonitrile can be effectively released by photolysis of TBD.HBPh4 salt, which represents a new family of short-wave UV photobase generators. This photobase generator enables the photoinduced living ring-opening polymerization of cyclic esters and the photoinduced cross-linking of various polymeric materials containing the hydroxyl-ester groups.