화학공학소재연구정보센터
Journal of Physical Chemistry, Vol.98, No.21, 5431-5434, 1994
2-Laser, 2-Color Photochemistry from Upper Triplet-States of 2-Bromonaphthalene and 9-Bromophenanthrene in Benzene
The photochemistry of 2-bromonaphthalene (BrN) and 2-bromophenanthrene (BrP) in benzene was examined using two-laser, two-color techniques. These experiments center on the photochemistry of the strongly absorbing triplet states of these molecules. Triplet photobleaching quantum yields in benzene are 0.12 and 0.15 for BrN and BrP, respectively. It is believed that these yields coincide with C-Br bond cleavage to yield in-cage radical pairs. Their magnitude reflects excited-state partitioning between C-Br bond cleavage and return to the lowest triplet surface. Bromine atoms were detected taking advantage of pi-complex formation in benzene with lambda(max) similar to 540 nm. Less than half of the bleaching events result in the formation of detectable bromine atoms. Geminate radical recombination of the radical pair to regenerate starting material must compete with cage escape, which accounts for the remaining bleaching events.