Cobalt-carbon bonds of various alkylcobalt(III) complexes, cis-[CoR2(bipy)2]ClO4 (R = Me, Et, or PhCH2; bipy = 2,2′-bipyridine), trans-[CoMe2(L)] (L = 3,9-dimethyl-4,8-diazaundeca-3,8-diene-2,10-dione dioximate), and [CoR(Hdmg)2(py)] (R = Me or Et; Hdmg = dimethylglyoximate; py = pyridine), are readily cleaved by iodine in carbon tetrachloride to yield alkyl iodides via photoinduced radical chain reactions with large quantum yields (e.g. Φ = 7.0 × 103) under low-energy irradiation (λ 517 nm). The rate-determining step in the radical chain reactions is suggested to be electron transfer from alkylcobalt(III) complexes to iodine atoms (I.) which are produced by the photodissociation of I2, based on the formation of by-products that could arise only via electron-transfer processes as well as the kinetic comparison between alkylcobalt(III) complexes and tetra-alkyltin compounds.
|Number of pages||6|
|Journal||Journal of the Chemical Society, Dalton Transactions|
|Publication status||Published - Dec 1 1990|
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