Kinetics and Mechanism of the Base Hydrolysis of Chloro-and Bromo(N-(2-pyridinylmethylene)-N'/-[ 3-[2-pyridinyl-methylene)amino]propyl]-1,3-propanediamine )cobalt(III)[CoLX]2+

Chemistry Department, University of St. Andrews, St. Andrews KY16 9ST, Scotland Manuscript received 29 April 1991 Complexes [CoLX]2+ (X= CI, Br) contain a single acidic proton and the site of conjugate base formation is thus defined. These complexes undergo extremely rapid base hydrolysis with \(\kappa\)o\(\vdash\) =1.83 x 10* dm1 mol-1 s-1 (X (I)and \(\kappa\)OH = 3.5 x 106 dm mol-1 s-1 (X= Br) at 25°. The corresponding activation parameters are \(\bigtriangleup\)H*=50.1 KJ mol-1,ΔS \(_{298}^\neq\) =+43 JK-1mol-1 (X= Cl) and \(\bigtriangleup\)H\(\neq\) =49 1 kJ mol-1 \(\bigtriangleup\)S\(_{298}^\neq\) =+ 45 JK-1 mol-1. Base hydrolysis of the chloro complex is subject to general base catalysis by OAc- indicating that rate determining proton transfer occurs in the base hydrolysis reaction