TRIPLET STATES AND cis-trans PHOTOISOMERIZATION PROCESSES IN THE SCHIFF BASES OF RETINAL ISOMERS |
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Authors: | T. Rosenfeld A. Alchalel M. Ottolenghi |
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Affiliation: | Department of Physical Chemistry, The Hebrew University, Jerusalem, Israel |
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Abstract: | Abstract —The triplet states of the n -butyl-amine Schiff bases of 11- cis , 9- cis , 13- cis and all- trans retinal are produced via triplet-triplet energy transfer. Their absorption spectra, peaking around 435 nm, and their decay kinetics are recorded using pulsed-laser photolysis. Direct-excitation (φDISO) and triplet-sensitized (φTISO) photoisomerization yields, determined using steady irradiation methods, are found to be: φTISO (9- cis ) = 0.06, φTISO (11- cis ) = 045, φTISO (13- cis ) = 008, φTISO (all- trans ) = 0.02-0.05, φDISO (11- cis , = (4 ± 1) × 10-3, φDISO (all- trans ) = (2 ± 1) × 10-3. The possible role of the triplet state in the isomerization of rhodospin is discussed. |
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