Octahedral cobalt(III) complexes of the chloropentammine type. Part XIII. cis-Chloro-2-methoxyethylamine- and cis-chloro-3-methoxy-propylamine-bis(ethylenediamine)cobalt(III) complexes

Abstract

Salts of one isomer of the chloro-2-methoxyethylamine- and chloro-3-methoxypropylamine-bis(ethylenediamine)-cobalt(III) cations have been prepared and characterised. Based on visible and i.r. absorption spectra, these complexes are assigned a cis configuration, with the amino-ether ligands occupying one co-ordination through nitrogen. The first-order rate constants for the solvolytic aquation of these cations have been determined at different temperatures and the Arrhenius parameters calculated. These results have been discussed in terms of a unimolecular exchange between a water molecule in the solvation shell and the chloro-ligand in the co-ordination shell of the complex. The second-order rate constants for the base hydrolysis of these cations have also been determined at 0° and ionic strength of 0·1M. This reaction is believed to take place by an S_N1/P mechanism.