The kinetics and mechanism of the
substitution of chloride ion and thiocyanate ion into the cis-chlorodimethylformamidebisethylenediaminecobalt(111) ion, cis-[CoCl(DMF) en2]2+,
have been studied in ,NN-dimethylformamide (DMF).
The chloride entry shows mixed kinetics
which are accounted for by two paths, a slow ion pair dissociation, and a fast
bimolecular attack of chloride on an ion pair. The steric course of the
reaction, which is chloride dependent, shows that the ion pair dissociative
mechanism is more important at low chloride concentrations.
The thiocyanate entry shows similar
characteristics. Thiocyanate enters faster than chloride in the bimolecular
path, but in the ion pair dissociative path, which is significant at lower
anion concentration, both chloride and thiocyanate enter at the same rate.
Kinetics and mechanism of the oxidation of thiocyanate ion by di-m-oxo-tetrakis(1,10-phenanthroline)-dimanganese (III,IV) ion in acid medium