73787-86-7Relevant articles and documents
Xenon Matrix Photochemistry of 1,1-Dichloroethene: Matrix-Dependent Surface Crossing and Hydrogen-Bonding Geometries
Laursen, Sandra L.,Pimentel, George C.
, p. 8175 - 8182 (2007/10/02)
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.
PHOTOSENSITIZED REACTION OF Hg(3P) ATOMS WITH THE DICHLOROETHENES IN KRYPTON MATRIX: TRIPLET SURFACE CHEMISTRY
Cartland, Harry E.,Pimentel, George C.
, p. 5485 - 5491 (2007/10/02)
The reactions between Hg(3P) atoms with the there dichloroethenes in krypton matrix at 12 K have been studied.In the absence of Hg, matrix photolysis with wavelengths longer than 200 nm gives isomerization as well as, for cis-dichloroethene (c-DCE) and 1,1-dichloroethene (1,1-DCE) but not for trans-dichloroethene (t-DCE), HCl elimination to give ClH.C2HCl.In the presence of Hg atoms and with excitation in the range 246-257 nm, HCl elimination is substantially reduced and, for c-DCE and 1,1-DCE, new products appear.These products are identified as Cl2.C2H2 and chlorovinyl mercuric chlorides, the latter the net result of mercury insertion into a carbon-chloride bond.The insertion product from c-DCE is identified as trans-2-chlorovinyl mercuric chloride and that from 1,1-DCE is probably 1-chlorovinyl mercuric chloride.The results indicate that in the krypton matrix, Hg(3P)-initiated chemistry takes place on a triplet surface that is not accessed with higher energy, singlet excitation.Furthermore, the absence of Cl2 elimination or insertion chemistry for t-DCE indicates that the role of Hg(3P) is not merely energy transfer but, instead, one that opens reaction channels not observed without Hg(3P).
