MECHANISM OF REACTIONS OF DIHYDROXOBIS(ETHYLENEDIAMINE)COBALT(III) CATIONS IN HIGHLY BASIC AQUEOUS SOLUTION

The rates of isomerization and of the racemization of the Co(en)2(OH)2+ ions have been measured over the temperature range 25-70°. The observed rates are independent of hydroxide concentration. The activation energies for the cis → trans change and for the trans → cis change are 29.5 and 28.5 kcal mol-1, respectively. The activation energy for the racemization is not constant over the temperature range. The mechanisms of oxygen exchange with solvent and of stereochemical change are discussed. The mechanism of the latter is intramolecular, and it is proposed that a twisting process is the most likely one. © 1969, American Chemical Society. All rights reserved.