Kinetics of the Formation of the Nickel(II) Complex with N, N' -Dimethylethylenediaminediacetic Acid and the Metal Exchange Reaction between N,N'-Dimethylethylenediaminediacetatonickel(II) and Copper(II)
Date of Award
Master of Arts
Dr. Ralph K. Steinhaus
Dr. Dean W. Cooke
Dr. H. Dale Warren
Masters Thesis-Open Access
The kinetics of the reaction of aquonickel (II) ion with N'N'-dimethlethylenediaminediacetic acid has been studied at 25°C and 0.1M iconic strength over a pH range of 6.0 to 9.3 using stopped-flow techniques. Formation reactions in all cases were first-order in Ni (II) and in ligand. The formation rate constant for the protonated and unprotonated species were evaluated and compared to their theoretical value. The rate-determining step is shown to be ring closure. A comparison of this system with other studies involving complexation of nickel (II) confirm the magnitude of the internal conjugate base effect and also shows a correlation between and the internal conjugate base rate enhancement and the structural environment of the nitrogen donor atom.
The exchange reaction between copper (II) and N,N'- dimethylethylenediaminediacetatonickelate (II) was studied at 25°C over a four fold variation was shown to be first-order in NiMEDDA and zero-order in copper. This zero-order dependence shows the inability of DMEDDA to unwrap from nickel and twist into a conformation suitable for bonding to copper prior to the rate limiting step.
Karel, "Kinetics of the Formation of the Nickel(II) Complex with N, N' -Dimethylethylenediaminediacetic Acid and the Metal Exchange Reaction between N,N'-Dimethylethylenediaminediacetatonickel(II) and Copper(II)" (1984). Master's Theses. 1533.