Abstract
Base hydrolysis of a series of pentakisalkylamine complexes of the form Co A.-,Cl2 + (A =
show a marked acceleration (>106) in rate relative to Co(NH3)sC12+. The rate enhancement is attributed to steric compres- sion in the deprotonated reactant which is relieved in the transition state. Evidence for the relative stabilization of the transition state and the deprotonated five-coordinate intermediate is given by an evaluation of nonbonded interactions and by competition studies using Na- and SCN“. Smaller rate variations for aquation of Cl- are also discussed.