65554-13-4Relevant academic research and scientific papers
Reactions of cobalt(II) macrocycles with alkyl and alkylperoxy radicals
Bakac, Andreja,Espenson, James H.
, p. 4319 - 4322 (2008/10/08)
The cobalt-carbon bond formation in the reactions of cobalt(II) macrocycles, LCoII (L = C-meso-Me6[14]aneN4, Me6[14]-4,11-dieneN4, corrin, tim), with primary alkyl and substituted primary alkyl radicals takes place with rate constants in the range 107-109 M-1 s-1. The kinetics are influenced by the nature of the macrocycle to a much greater extent than by the nature of the radicals, such that all the rate constants, kCo, for a given cobalt complex fall within a factor of ～2. For example, the values of 10-8kCo/M-1 s-1 for B12r are 4.2 (R = CH3), 5.1 (C2H5), 5.1 (CH3OCH2), 5.8 (ClCH2), 6.1 (C3H7), and 9.1 (BrCH2). The alkylperoxy radicals RO2? (R = CH3, C2H5, BrCH2) react with Co(tim)(H2O)22+ with a rate constant k = 1.4 × 108 M-1 s-1.
Photochemical generation of alkyl radicals and their reactions with methyl viologen radical cation and with transition-metal complexes in aqueous solution
Bakac, Andreja,Espenson, James H.
, p. 3901 - 3904 (2008/10/08)
The irradiation of aqueous solutions of RCo([14]aneN4)(H2O)2+ (R = CH3, C2H5, 1-C3H7, CH2Cl, CH2Br, CH2OCH3) with visible light, λ ≤ 500 nm, results in the homolysis of the cobalt-carbon bond. These complexes are quite unreactive toward a variety of dealkylating and redox reagents and thus represent a convenient source of small unstabilized carbon-centered radicals in the presence of potential substrates. The radicals react rapidly with the methyl viologen radical cation, kMV = (1-2) × 109 M-1 s-1. The kinetics of the formation of RCr2+ and RCo([14]aneN4)(H2O)2+ in the reactions of radicals with Cr2+ and Co([14]-aneN4)(H2O)22+, respectively, were studied by using MV+ as a probe. The respective rate constants have values kCr = (1.9-2.4) × 108 M-1 s-1 and kCo = (1-2) × 107 M-1 s-1 for all the radicals examined.
