The rates of β-amine elimination from CuII-CH(CH2NH3)3+2 and CuII-CH2CH2NH2+3 have been found to be about two orders of magnitude lower than those from CuII-CH[CH2N(CH3)2H]3+2 and CuII-CH2CH2N(C2H5) 2H2+ in aqueous solutions. The results indicate that N-alkylation increases the rate of β-amine elimination, whereas previous results demonstrated that O-alkylation decreases the rate of β-elimination of HOR′ from (H2O)5CrIII - CH2CH2OR′2+ (R′ = H, C2H5). These opposite trends are in accord with expectations based on the assumption that the rate of β elimination of X- from LmM(n + 1)-CR1R2CR3R4Xn+ is correlated to the C-X bond strength. A mechanism of activation 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.