New Photosensitive Polymers:  Synthesis and Free Radical Polymerization of Oxypyridinium and Oxyisoquinolinium Functionalized Methacrylate and Styrene Derivatives

Polymerizable hydroxypyridinium and hydroxyisoquinolinium salts 1a−4a, 2d, and 3d have been prepared from vinylbenzyl chloride or glycidyl methacrylate and 3-hydroxypyridine (2), 4- or 5-hydroxyisoquinoline (1, 3), and 8-hydroxyquinoline (4). Radical homo- and copolymerization with styrene or methyl methacrylate of the salts 1a−3a, 2d, and 3d produced (co)polymers 1e, 2e, 2f, 3f, 1g, 2g, 2h, and 3h. The photosensitive dipolar oxypyridinium or oxyisochinolinium betaine structures were generated in solutions with triethylamine from the low molecular weight and polymeric salt precursors. For the model compounds 1b−4b and (co)polymers 1e, 2e, 2f, 3f, 1g, 2g, 2h, and 3h, the degradation of the longest wavelength absorption of this betaine structure was detected during UV irradiation. UV irradiation of the model compound N-benzyl-4-hydroxyisochinolinium chloride (1b) in the presence of triethylamine produced the expected aziridine type structure 1k by intramolecular cyclization.