50835-27-3Relevant academic research and scientific papers
Xenon Matrix Photochemistry of 1,1-Dichloroethene: Matrix-Dependent Surface Crossing and Hydrogen-Bonding Geometries
Laursen, Sandra L.,Pimentel, George C.
, p. 8175 - 8182 (1990)
The photoproducts of 1,1-dichloroethene (DCE) in Xe matrix at 12 K differ from those observed in Kr.With 239-nm photolysis, chlorine is eliminated from 1,1-DCE in solid Xe, but not in Kr, although HCl elimination and DCE isomerization occur in both matrices.Just as in the 1,2-dichloroethenes, Cl2 elimination proceeds in the heavy Xe matrix via spin-orbit-enhanced intersystem crossing to a triplet reaction surface.At higher photolysis energies, a novel product appears in Xe and is identified with the aid of isotopic substitution as a second HCl*C2HCl isomer, ?-hydrogen-bonded through the acetylenic proton.The product dependence on wavelength, parent, and matrix indicates that it is formed through a triplet-surface process under geometric constraints specific to the 1,1 isomer.Loss of Cl from a dissociative triplett state to form an excited chlorovinyl radical, with further cage reaction of the energetic fragments, is postulated.
Matrix-Induced Intersystem Crossing in the Photochemistry of the 1,2-Dichloroethenes
Laursen, Sandra L.,Pimentel, George C.
, p. 2328 - 2333 (2007/10/02)
The photoproducts of the 1,2-dichloroethenes (DCE) in xenon matrix at 12 K differ from those observed in krypton matrix.In xenon, photolysis at 237 nm of both cis- and trans-dichloroethene results in elimination of both Cl2 and HCl as well as isomerization, whereas only HCl elimination and isomerization are observed in krypton.Longer wavelength irradiation has no effect on either DCE in Kr but produces small, distinct amounts of products in Xe.The results indicate that in xenon, chemistry is occuring through a triplet state as well as from the directly excited singlet state.Enchanced spin-orbit coupling in the heavy-atom environment facilitates intersystem crossing from the initial singlet to a triplet surface, as well as, no doubt enhanced absorption directly into the triplet state.These effects provide access to the normally spin-forbidden chlorine elimination channel.The appearance of products in Xe at the lower photon energies is ascribed to direct T1 0 absorption, assisted by the external heavy atom.
