38091-14-4Relevant academic research and scientific papers
An EPR, ENDOR and ESEEM study of the benzene radical cation in CFCl3 matrix: Isotopic substitution effects on structure and dynamics
Kadam, Ramakant M.,Itagaki, Yoshiteru,Benetis, Nikolas P.,Lund, Anders,Erickson, Roland,Huber, Martina,Hilczer, Wojciech
, p. 4967 - 4974 (1999)
A combination of EPR lineshapes, ENDOR and ESEEM was performed to investigate possible Jahn-Teller effects in mono- and perdeuterated benzene radical cation in a polycrystalline CFCl3 matrix. Replacement of one proton by a deuteron was utilized to exclude significantly fast quantum pseudorotation and overall rotary motion below 77 K. Clear evidence was obtained for static Jahn-Teller distortion at temperatures up to 30 K, with major spin densities on two para positions (1 and 4) in agreement with a b(2g)(χ(s) +) localized orbital. From ENDOR measurements of C6H5D+, the isotropic and dipolar coupling constants for protons occupying both high and low spin density positions were accurately measured. Additional ESEEM experiments and simulations confirmed the results, indicating further that deuteron-isotope substitution does not disturb appreciably the fundamental dynamics of the benzene radical benzene. The hyperfine tensors of C6D6 + in the Jahn-Teller distorted configuration obtained by ESEEM were analogous to those of fully protonated compounds, but the components were scaled by the magnetic moment ratio of deuterons to protons.
Radical Intermediates in the Photoinduced Formation of Benzene Cation-Radicals over H-ZSM-5 Zeolites
Bolshov, Vadim A.,Volodin, Alexander M.,Zhidomirov, George M.,Shubin, Alexander A.,Bedilo, Alexander F.
, p. 7551 - 7554 (1994)
Radical particles are shown to appear under irradiation (hv >= 2.8 eV) of H-ZSM-5 zeolites with adsorbed benzene.The particles appeared to be benzene cation-radical precursors over the zeolite.Heating resulted in irreversible destruction of the particles and emergence of a benzene cation-radical spectrum.The obtained radicals have no detectable hyperfine splittings on the protons, their spectrum remaining almost the same when deuterobenzene was used.The possible structure of the particles is discussed.
Solvent, Isotope, and Substituent Effects on the Bimolecular Electron Transfer Reaction between Chlorine Oxide and Benzenes
Doolen, Robert,Simon, John D.,Baldridge, Kim K.
, p. 13938 - 13947 (2007/10/02)
The rate of back electron transfer following photoexcitation of ground-state complexes between ClO and aromatic molecules in nitrile solvents is examined.Both solvent effects on a single molecular complex and a series of complexes within a single solvent are analyzed in terms of commonly used theoretical models.For a single molecular complex (ClO-benzene), the rate of back electron transfer decreases with decreasing solvent dielectric constant and is temperature independent.This indicates that the reaction rate decreases with increasing exothermicity, behavior consistent with that expected for reactions in the Marcus inverted region.Investigation of the dependence of the reaction rate on exothermicity using a series of substituted benzenes as acceptor molecules in a single solvent revealed increasing reaction rates with increasing driving force, opposite to that observed upon varying solvent.Studies of deuteration effects on the reaction rate constant suggest that the origin of these disparate predictions arises from the assumptions made in carrying out the data analysis on the series of donor-acceptor complexes studied.In particular, both the inner-sphere and outer-sphere contributions to the reorganization energy are not constant for the set of molecules studied.This study demonstrates the difficulty in extracting accurate information on the reaction exothermicity, reorganization energy, and electronic coupling from measured rate constants.
