KINETICS AND MECHANISM OF DISSOCIATION OF SOME BIS-(N¹-SUBSTITUTED BIGUANIDE) COMPLEXES OF NICKEL(II) IN AQUEOUS ACID

Abstract

The rater of dirsodstion of bL-("-methylbiguonide)nickel~I) and bb~-phenylbigunnide)nickel(Il) in aqucow acid have been rtudier by the rtopped-fbw rpectrophotmetric technique. The reactions occur in two conrecutivc rtep, the fint being fiuter than the second, ultimately fonning the aquometal ion and the prOtOMted band. For each rtep the rate b acid dependent PI exprewd by k, = kk[H*], where k, i~ the obierved rate constant. The results are consistent with a machanitm involving an aarbted dusodatin pzocnar involving the protonatad cornpiexu with conriderable solvent puticipetion in the tranrition date. The observed lability order b Ni(PhbigH)r > Ni(MebigH):* > Ni(BiigH):*.