Temperature dependence of the 1,6-diphenyl-1,3,5-hexatriene triplet lifetime in solution and theoretical evaluation of triplet conformer interconversion.
The 1,6-diphenyl-1,3,5-hexatriene (DPH) triplet decay rate constant in degassed benzene is strongly temperature-dependent. Photostationary states for the fluorenone-sensitized photoisomerization of DPH in degassed methylcyclohexane (MCH) favor the all-trans isomer and become richer in the cis isomers as the temperature is increased. The results are interpreted in terms of competing decays from equilibrated triplet conformers on the basis of the experimentally derived DPH triplet potential energy surface [Saltiel, J.; Crowder, J. M.; Wang, S. J. Am. Chem. Soc. 1999, 121, 895 902; 5352]. Calculated geometries and energy differences [B3LYP/6-311+G(d,p)] are consistent with the experimental model.
Saltiel
Jack
J
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, USA. saltiel@chem.fsu.edu
Klima
Rodney
R
van de Burgt
L J
LJ
Wang
Shujun
S
Dmitrenko
Olga
O