Octahedral cobalt(III) complexes of the chloropentammine type. XIX. The preparation, properties, and reactions of some Chlorobenzylaminebis-(ethylenediamine)cobalt(III) salts and related complexes

Abstract

Salts of one isomeric series of chlorobenzylaminebis(ethylenediamine)- cobalt-(III) type of cations have been prepared using a variety of benzylamine derivatives as ligands. They are tentatively assigned a cis-configuration on the basis of their visible spectra. The first- order rate constants for their solvolytic aquation have been measured. Both resonance contributions and steric factors from the benzyl radical, as well as inductive effects of its substituents, all have negligibly small influences on the rate of reaction. The second-order rate constants for the hydrolysis of these cations by base have also been determined. The labilizing powers of the benzylamine ligands in this reaction are very similar to those of open-chain aliphatic amines, and significantly different from those of aromatic amines. To see if reactivities depend on the distance of separation between cobalt and the benzene ring, the experiments are extended to the chloro(β- phenylethylamine)bis(ethylenediamine)cobalt(III) type of complexes.