EFFECT OF N-ALKYLATION ON THE RATE OF BETA-AMINE ELIMINATION FROM TRANSIENTS WITH CU-II-CARBON SIGMA-BONDS

The rates of beta-amine elimination from CUII-CH(CH2NH3)(2)(3+) and CU II-CH2CH2NH32+ have been found to be about two orders of magnitude low er than those from Cu-II-CH[CH2N(CH3)(2)H](3+)(2) and CUII-CH2CH2N(C2H 5H2+ in aqueous solutions. The results indicate that N-alkylation incr eases the rate of beta-amine elimination, whereas previous results dem onstrated that O-alkylation decreases the rate of beta-elimination of HOR' from (H2O)(5)Cr-III-CH(2)CH(2)OR'(2+) (R' = H, C2H5). These oppos ite trends are in accord with expectations based on the assumption tha t the rate of beta elimination of X(-) from L(m)M((n+1))-CR(1)R(2)CR(3 )R(4)X(n+) is correlated to the C-X bond strength. A mechanism of acti vation from the reaction is formulated, based on the Shaik-Pross curve -crossing model. The model provides a basis for the assumption of bond strength controlled rates.