53553-61-0Relevant articles and documents
SPECTROSCOPIC AND CHEMICAL EVIDENCE FOR METHYLENE SINGLET-TRIPLET INTERSYSTEM CROSSING IN SOLUTION
Turro, Nicholas J.,Cha, Yuan
, p. 6149 - 6152 (1986)
Singlet-triplet intersystem crossing of methylene in perfluorohexane solution has been investigated by CIDNP.Evidence of this process is shown by the polarized absorption 1H-NMR signal of Cl3C-CH2D, a triplet product, which is obtained upon direct irradiation of diazirine in perfluorohexane solution containing saturated deuteriochloroform.These results are confirmed by product analysis as a function of dilution by perfluorohexane.The rate constant for intersystem crossing for singlet methylene to triplet methylene is evaluated as ca. 8E8 1/s from the data.
Reactivity and Intersystem Crossing of Singlet Methylene in Solution
Turro, Nicholas J.,Cha, Yuan,Gould, Ian R.
, p. 2101 - 2107 (2007/10/02)
Evidence is reported wich demonstrates that singlet methylene, produced from the photolysis of diazomethane or diazirine undergoes intersystem crossing to form triplet methylene in perfluorohexane solvent.The results of triplet sensitized photolysis and of direct photolysis experiments with dilute concentrations of substrate (cis- and trans-2-pentene and chloroform) appear to be essentially identical.Stern-Volmer analyses of the competition kinetics between acetonitrile and 2-pentenes or chloroform for singlet methylene are consistent with the near diffusion controlled reactivity of singlet methylene.With the assumption of diffusion-controlled reactions for singlet methylene, plots of the quantum yield for singlet vs. triplet reaction for methylene allow the first estimate (-1) of the rate of intersystem crossing of singlet methylene in the condensed phase.This value is considerably smaller than the value that is extrapolated to the solution phase from results in the gas phase.The possible reasons for this difference are discussed.