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8315389 
Journal Article 
Kinetics of the Oxidation of Chromium(II) by Hydrogen Peroxide: Flash-Photolytic and Stopped-Flow Studies Based on Radical-Trapping Reactions 
Bakaä, A; Espenson, JH 
1983 
Yes 
Inorganic Chemistry
ISSN: 0020-1669
EISSN: 1520-510X 
22 
5 
779-783 
English 
Thermally stable organochromium complexes such as CrCHCl22+ and CrCH2OCH32+ undergo homolytic Cr-C bond cleavage upon irradiation with unfiltered light from xenon flash lamps: CrR2+ [formula omitted] Cr2+ + R. This enables determination of the rate constant k1 for the reaction Cr2+ + H2O2 CrOH2+ + ·OH, because this is the rate-limiting step in a sequence of reactions. The hydroxyl radicals react very rapidly with organic and inorganic solutes to yield radicals that in turn react rapidly with Cr2+, producing intensely colored chromium complexes. The formation of these species was monitored spectrophotometrically. Some experiments were also done by the stopped-flow technique using solutions of Cr2+ and H2O2 in the presence of an organic solute or KI. The two techniques yielded identical results. In aqueous solution at 25 °C and 1.0 M ionic strength (HClO4 + LiClO4), with methanol, ethanol, 2-propanol, dimethyl ether, diethyl ether, dimethyl sulfoxide, and potassium iodide as solutes, the value of the rate constant k1 is (7.06 ± 0.04) × 104 M-1 s-1. © 1983, American Chemical Society. All rights reserved.