Date of Award

Winter 1980

Project Type


Program or Major


Degree Name

Doctor of Philosophy


Five-coordinate complexes of nickel (II), cobalt (II), and copper (II), were prepared from the quadridentate ligand tris-(2-dimethylaminoethyl)-amine, a ligand which forms high-spin trigonal bipyramidal complexes. Previous studies of the dissociation of these complexes in aqueous perchloric acid revealed a single step kinetic process.

Dissociation of the cobalt (II) complex was undertaken in acetonitrile, in dimethyl sulfoxide, and in N,N-dimethylformamide, with monochloroacetic acid as the dissociating agent. Multi-step kinetic behavior was observed. The rate-determining step was considerably faster in dimethyl sulfoxide and in N,N-dimethylformamide than in acetonitrile and in water. Possible mechanisms for the dissociation reaction are described and discussed in terms of solvent properties and crystal field energetics.

Further studies were undertaken in mixed solvents such as dimethyl sulfoxide/water and N,N-dimethylformamide/water mixtures, to determine the effect of the presence of water on the mechanism of the dissociation reaction.

Kinetic measurements were obtained with a Durrum-Gibson stopped-flow spectrophotometer.