KINETICS OF FORMATION AND DISSOCIATION OF [CR3O(O2CCH3)(6)(UREA)(3)](- AN EXAMPLE OF STATISTICALLY CONTROLLED KINETICS AND EQUILIBRIUM() )

Kinetics of the overall reaction [Cr3O(O2CCH3)(6)(H2O)(3)](+) + 3 urea reversible arrow [Cr3O(O2CCH3)(6)(urea)(3)](+) + 3H(2)O have been stu died spectrophotometrically. Monophasic kinetics were observed in both directions. The reverse steps, of urea dissociation, were monitored u sing an analytical technique which permits direct determination of the concentration of liberated urea and does not require knowledge of ext inction coefficients of intermediate species. Results imply that conse cutive steps occur with rate constants in close to the statistical rat ios of k(1):k(2):k(3) = 3:2:1 and k(-1):k(-2):k(-3) = 1:2:3. Rates ind icate strong labilization of urea, compared to the case of mononuclear complex [Cr(urea)(6)](3+).