Faculty Collaboration Database

Electron transfer reaction of oxo(salen)chromium(V) ion with anilines. Inorg Chem 2004 Sep 06;43(18):5744-53

Date

08/31/2004

Pubmed ID

15332827

DOI

10.1021/ic049482w

Scopus ID

2-s2.0-4444249254 (requires institutional sign-in at Scopus site)   39 Citations

Abstract

The kinetics of oxidation of 16 meta-, ortho-, and para-substituted anilines with nine oxo(salen)chromium(V) ions have been studied by spectrophotometric, ESIMS, and EPR techniques. During the course of the reaction, two new peaks with lambda(max) at 470 and 730 nm appear in the absorption spectrum, and these peaks are due to the formation of emeraldine forms of oligomers of aniline supported by the ESIMS peaks with m/z values 274 and 365 (for the trimer and tetramer of aniline). The rate of the reaction is highly sensitive to the change of substituents in the aryl moiety of aniline and in the salen ligand of chromium(V) complexes. Application of the Hammett equation to analyze kinetic data yields a rho value of -3.8 for the substituent variation in aniline and +2.2 for the substituent variation in the salen ligand of the metal complex. On the basis of the spectral, kinetic, and product analysis studies, a mechanism involving an electron transfer from the nitrogen of aniline to the metal complex in the rate controlling step has been proposed. The Marcus equation has been successfully applied to this system, and the calculated values are compliant with the measured values.

Author List

Premsingh S, Venkataramanan NS, Rajagopal S, Mirza SP, Vairamani M, Rao PS, Velavan K

MESH terms used to index this publication - Major topics in bold

Acrylonitrile
Aniline Compounds
Chromium
Electrochemistry
Electrons
Kinetics
Molecular Structure
Organometallic Compounds
Oxidation-Reduction
Spectrometry, Mass, Electrospray Ionization