Kinetics and mechanism of iodination of para-substituted benzylbis(dimethylglyoximato)(pyridine)cobalt(III). High reactivity of the base-off form

Article abstract of DOI:10.1021/ic50217a051

A kinetic study of the iodination of p-XC₆H₄CH₂Co(DH)₂(py) (X = methoxy, methyl, H, chloro, nitro; DH = monoanion of dimethylglyoxime; py = pyridine) revealed the rate-determining dissociation of pyridine and subsequent rapid reaction of the base-free form with iodine. The high reactivity of the base-free form is discussed in relation to inner-sphere electron transfer. The rates of dissociation of pyridine showed a Hammett-like linear free-energy relationship with a ρ⁺ of -1.48.