Abstract

The reactions of hydrazine, methylhydrazine, and 1,1-dimethylhydrazine with trans-dichlorobis(ethylenediamine)cobalt(III) chloride in concentrated and dilute solutions are studied. In concentrated solution, there is a reduction by hydrazine to form the insoluble polymeric [Co^II(N₂H₄)₂Cl₂]_n, a substitution by methylhydrazine to form chlorobis(ethylenediamine)methylhydrazinecobalt(III) chloride, and a disproportionation with 1,1-dimethylhydrazine to form tris(ethylenediamine)cobalt(III) chloride. In dilute solution, the reaction observed is a hydroxide substitution by hydrolysis of 1,1- dimethylhydrazine, a reduction to soluble cobalt(II)-ethylenediamine species with hydrazine, and a mixture of both processes for methylhydrazine. The chlorobis(ethylenediamine)methylhydrazinecobalt-(III) chloride obtained is a new complex, and is assigned a cis configuration on the basis of spectroscopic observations. The kinetics of its intramolecular electron-transfer, as well as its acid and base hydrolyses are also studied.