Strongly modified [2,2 '-bipyridyl]-3,3 '-diol (BP(OH)(2)): a system undergoing excited state intramolecular proton transfer as a photostabilizer of polymers and as a solar energy collector

Six new compounds, derivatives of [2,2'-bipyridyl]-3.3'-diol (BP(OH)(2)) ar e recommended as useful modifications of the parent structure. One group, t hree molecules with conjugate aromatic substituents (6-methyl-6'-styryl-BP( OH)(2), 6-(4-methoxystyryl)-6'-methyl-B P(OH)(2), 6-methyl-6'-(4-phenylstyr yl)-BP(OH)(2)), are potential solar energy concentrators - they have absorp tion spectra red shifted with respect to BP(OH)2. To the second group belon g the derivatives with the aliphatic side chains, better "accepted" by poly ethylene than the parent molecule. These compounds are designed to improve their function as photostabilizers of polymers. All six new compounds were synthesized and their photophysical characteristics were studied. Absorptio n spectra, phototautomeric fluorescences and their excitation spectra. as w ell as quantum yields and lifetimes are reported. (C) 2001 Elsevier Science B.V. All rights reserved.