Inorganic Chemistry, Vol.46, No.7, 2353-2355, 2007
Amide hydrolysis reactivity of a N4O-ligated zinc complex: Comparison of kinetic and themodynamic parameters with those of the corresponding amide methanolysis reaction
Treatment of the mononuclear amide-appended zinc complex [(ppbpa)Zn](ClO4)(2) (1(ClO4)(2)) with Me4NOH center dot 5H(2)O in CD3CN/D2O (3:1) results in the formation of the deprotonated amide species [(ppbpa(-))Zn]ClO4 (2). Upon heating in CD3CN/D2O, this complex undergoes amide hydrolysis to produce a zinc carboxylate product, [(ambpa)Zn(O2CC(CH3)(3))]ClO4 (3). X-ray crystallography, H-1 and C-13 NMR, IR, and elemental analysis were used to characterize 3. The hydrolysis reaction of 1(ClO4)(2) exhibits saturation kinetic behavior with respect to the concentration of D2O. Variable-temperature kinetic studies of the amide hydrolysis reaction yielded Delta H = 18.0(5) kcal/mol and Delta S = -22(2) eu. These activation parameters are compared to those of the corresponding amide methanolysis reaction of 1(ClO4)(2).