75195-55-0Relevant articles and documents
Application of Time-Resolved Chemically Induced Dynamic Electron Polarization and Electron Spin Resonance Techniques to the Quenching of Quinone Triplets by Organometal Donors
Chen, K. S.,Wan, J. K. S.,Kochi, J. K.
, p. 1726 - 1731 (1981)
Time-resolved CIDEP is successfully applied to the quenching of carbonyl triplets generated photochemically from various quinones.Organometals as quenchers yield paramagnetic organometal adducts of quinones, the ESR parameters and T1 relaxation times of which are reported.An electron-transfer mechanism for the quenching of carbonyl triplets by organometals used in this study is derived from their low ionization potentials similar to those of amines.As such, it can be directly related to organometals as electron donors in thermal processes, in which electron transfer has been shown independently by the deliberate photochemical pumping of the charge-transfer band.The time-resolvced CIDEP technique allows the very short T1 spin-lattice relaxation times to be measured for various organometallic radicals.
Radical Intermediates in the Photoreaction between Disulfides and Acylsilanes
Alberti, Angelo,Degl'Innocenti, Alessandro,Grossi, Loris,Lunazzi, Lodovico
, p. 4613 - 4616 (2007/10/02)
Photolysis of cylopropane solutions of a number of disulfides RSSR (R = Me, n-Bu, CF3) in the presence of acylsilanes R'C(O)SiMe3 led to radicals of general structure R'C(OSiMe3)SR which have been detected by EPR spectroscopy.The structure of the observed paramagnetic species has been ascertained by producing PhC(OSiMe3)SMe via an alternative route, i.e., by reacting Me3Si radicals with the thio ester PhC(O)SMe.The lifetime of these radicals varies considerably with the bulkiness of the substituents in the neighborhood of the radical center.The decay rates as a funct ion of temperature, together with the corresponding activation parameters, have been determined for the hindered t-BuC(OSiMe3)SCF3 radical; it is suggested that the decay process involves an equilibrium with a dimeric species.A number of possible reaction sequences leading to these radicals have been examined, although the actual mechanism is as yet unclear.