Effects of Halide Ions and Carbon Monoxide on the Reactions of Iron(III) with Alkyl Radicals

In aqueous Solutions in the presence of carbon monoxide, the Fenton-like reactions between Fe(H2O)32+ and alkyl hydroperoxides (RC(CH3)2OOH, R = CH3, C2H5) readily produce acyl radicals, R•CO. For R = CH3, the resulting acetyl radicals reduce Fe(H2O)63+, k = 6 × 105 mol-1 dm3 s-1. The reaction of Fe(H2O)63+ with •CH3 is much slower, k ≈ 4 × 103 mol-1 dm3 s-1. Halide ions have an accelerating effect and lead to the formation of halomethanes. The rate constant for the reaction Fe(H2O)5Br2+ + #CH3 -> CH3Br + Fe(H2O)62+ is greater than 108 mol-1 dm3 s-1

Radical Kinetics as a Mechanistic and Analytical Tool

Thermal and photochemical methods for the generation of free radicals, and the kinetics of radical reactions with organic, inorganic and organometal- lic substrates are discussed. Both direct and competition kinetic methods are described. The latter are based on either product analysis or the kinetic effect of the substrate on the rate of disappearance of the radical precursor. Direct measurements often utilize kinetic probes, some of which are stable free radicals. A method for the generation of sulfur radicals from carbon radicals and thiols, and several reactions of sulfur radicals sure also described

Effects of Halide Ions and Carbon Monoxide on the Reactions of Iron(III) with Alkyl Radicals

In aqueous Solutions in the presence of carbon monoxide, the Fenton-like reactions between Fe(H2O)32+ and alkyl hydroperoxides (RC(CH3)2OOH, R = CH3, C2H5) readily produce acyl radicals, R•CO. For R = CH3, the resulting acetyl radicals reduce Fe(H2O)63+, k = 6 × 105 mol-1 dm3 s-1. The reaction of Fe(H2O)63+ with •CH3 is much slower, k ≈ 4 × 103 mol-1 dm3 s-1. Halide ions have an accelerating effect and lead to the formation of halomethanes. The rate constant for the reaction Fe(H2O)5Br2+ + #CH3 -> CH3Br + Fe(H2O)62+ is greater than 108 mol-1 dm3 s-1

Kinetics and Mechanism of the Reaction between Mercury(II) and a Series of Macrocyclic Organochromium Cations

Kinetic data are presented for the reaction of alkylchromium complexes (H2O)([14]aneN4)CrR2+ ([14]aneN4 = 1,4,8,11-tetraazacyclo-tetradecane) with Hg2+ via electrophilic substitution. The rate constants decrease in the order CH3 (1.1 × 106 mol-1 dm3 s-1) > C2H5 (7.7 × 102) > C3H7 (59) > 2-C3H7 (0.12) > CH2C(CH3)3 (0.0086). A series of meta and para substituted benzyl complexes obey a Ham-mett relationship with the reaction constant ρ = -1.66, consistent with electrophilic substitution at α-carbon

Radical Kinetics as a Mechanistic and Analytical Tool

Thermal and photochemical methods for the generation of free radicals, and the kinetics of radical reactions with organic, inorganic and organometal- lic substrates are discussed. Both direct and competition kinetic methods are described. The latter are based on either product analysis or the kinetic effect of the substrate on the rate of disappearance of the radical precursor. Direct measurements often utilize kinetic probes, some of which are stable free radicals. A method for the generation of sulfur radicals from carbon radicals and thiols, and several reactions of sulfur radicals sure also described