Exploring chromophore tethered aminoethers as potential photoinitiators for controlled radical polymerization

Compounds 1-4 containing various light absorbing chromophores attached cova lently to a hindered aminoether (2,2,6,6-tetramethyl-1-piperidinyloxy (TEMP O) aminoether) were synthesized, and their photochemistry and photophysics studied in an attempt to develop photoinitiators for radical "living" polym erization. Significant shortening of the chromophore's triplet lifetime was observed in 1-4 as compared to analogous compounds containing no alkylated TEMPO moiety, which suggests an intramolecular quenching of the excited ch romophore by the aminoether functionality. The efficiency of the quenching process depends on the chromophore. Employing 1-4 as unimolecular photoinit iators for styrene "living" polymerization was proven to be difficult due t o rapid quenching of the excited state of the initiator by this monomer. Co mpound 4 was demonstrated as an initiator for controlled photopolymerizatio n of methyl methacrylate. (C) 1999 Elsevier Science Ltd. All rights reserve d.