61219-63-4Relevant articles and documents
Solvent effects on the reduction mechanism of 9-chloroanthracene, 3-nitrobenzyl chloride and 3-chloroacetophenone
Jensen, Henrik,Daasbjerg, Kim
, p. 1151 - 1164 (2007/10/03)
The reduction mechanism of 9-chloroanthracene, 3-nitrobenzyl chloride and 3-chloroacetophenone has been investigated in detail by means of cyclic voltammetry and controlled potential bulk electrolysis. The investigation was carried out in a number of aprotic solvents in order to elucidate the importance of solvation phenomena on the various parameters associated with the reaction mechanism, i.e., clevage, hydrogen abstraction, protonation and dimerization rate constants as well as standard potentials. In this connection, the influence of the supporting electrolyte in terms of ion pairing and double layer effects has been considered. For the radical anions of 9-chloroanthracene and 3-nitrobenzyl chloride the logarithm of the cleavage rate constant shows a linear dependence on the Gutmann acceptor number and donor number, respectively, whereas no clear-cut correlation can be observed in the case of the radical anion of 3-chloroacetophenone. The rate constant obtained for the protonation reaction between 3-nitrobenzyl anion and 3-nitrobenzyl chloride is to an even higher extent influenced by the nature of the solvent. The trends in the solvent effects are discussed. Acta Chemica Scandinavica 1998.
Theory of Intramolecular Electron Transfer Reactions in Anion Radicals of Nitrobenzyl Halides
Miller, Kristine E.,Kozak, John J.
, p. 401 - 403 (2007/10/02)
Recently, we have suggested a lattice-based theory of chemical reactivity in which quantum and statistical mechanical arguments are combined to yield a method for calculating rate constants for certain classes of reactions.We present here the first concrete application of this theory and calculate the first-order rate constants for dehalogenation of the ortho-, meta-, and para-substituted nitrobenzyl chloride anion radicals.Our theoretical results are obtained by calculating the ? orbital spin populations of the anion radicals (MO calculations using the GAUSSIAN 82 series of programs), using the consequent values to distinguish the ortho, meta, and para sites, and then calculating the rate constants using a lattice statistical approach, the latter based on a theory presented recently.Apart from the limitations of the MO calculations and the neglect of solvent effects, the method involves no further assumptions or parameters.The theoretical estimates are in good agreement with the experimental rate constants.
Intramolecular Electron Transfer in the Anion Radicals of Nitrobenzyl Halides
Neta, P.,Behar, D.
, p. 4798 - 4802 (2007/10/02)
One-electron reduction of nitrobenzyl halides produces the anion radicals which subsequently undergo intramolecular electron transfer and decompose into nitrobenzyl radicals and halide ions.The optical absorption spectra of the initial anion radicals (λmax ca. 300-310 nm) and the subsequently formed nitrobenzyl radicals (λmax = 359 and 400 for the para and ortho, respectively) are quite intense (ε ca. 104 M-1 cm-1 in most cases) and significantly different.This enables identification of the various species and measurement of the rates of intramolecular electron transfer or C-X bond scission.The rates are 4*103, 1.7*105, and 5.7*105 s-1 for p-nitrobenzyl chloride, bromide, and iodide, respectively.The ortho derivatives decomposed nearly twice as rapidly while the meta decomposed much more slowly.The anion radical of p-nitrobenzyl bromide has pKa = 2.8, and the protonated form is found to undergo the intramolecular transfer ca. 60 times more slowly than the anion radical.The pattern of reactivity of the various anion radicals is rationalized in terms of spin density and charge distribution at the various positions on the ring and in terms of the electrophilicities of the halogens.
