Kinetics and reaction mechanisms of complexes with cobalt-carbon σ bonds of the type {(NH₃)₅Co-R}ⁿ⁺ in aqueous solutions, a pulse radiolysis study

The kinetics of formation of complexes with cobalt-carbon σ bonds in the reaction between {Co^II(NH₃)₅H₂O}²⁺ or {Co^II(NH₃)₆}²⁺ with different aliphatic radicals was studied in aqueous solutions using the pulse radiolysis technique, The formation of the complexes {(NH₃)₅Com^III-R}ⁿ⁺ obey pseudo first order rate laws and the rate constants for R = CH₃ and CH₂CO₂^- are (3.0±0.3)x1O⁷ and (2.1±0.3)x10⁷ m^-1s^-1, respectively. The UV/Vis spectra of the complexes are reported and found to be in agreement with previous results for analogous complexes. The results point out that the reactions (NH₃)₅Con^III-R + R + NH₃ → Co(NH₃)₆²⁺ + R₂ are fast thus limiting the radical route as a synthetic tool for the (NH₃)₅Com^III-R complexes.