Chemistry and Biochemistry
Bayer School of Natural and Environmental Sciences
Jeffry D. Madura
Jeffery D. Evanseck
Charles F. Kahle
Nitrile Anion, Solvation, Electronic structure calculation, Density functional theory, Ab initio calculation, Acetonitrile anion, Transition structure
This Ph.D. dissertation is focused on the investigation the structure of nitrile anion containing molecules and how the structure and reactivity of those molecules are affected by solvation and counter ion. A systematic approach was employed in this investigation, beginning with an evaluation of the accuracy of three commonly used model chemistries (Hartree-Fock (HF), Second-order Møller-Plesset perturbation theory (MP2), the Becke three-parameter exchange functional coupled with the nonlocal correlation functional of Lee, Yang, and Parr (B3LYP), all paired with the 6-31+G(d) basis set). A series of complexes of various cations with a number of explicit molecules of tetrahydrofuran (THF) and dimethyl ether (DME) were studied with these model chemistries and the results were compared, where possible, with experimental results. From this work, it was determined that the B3LYP models gave the most accurate results for the complexes in question. This work was then extended to acetonitrile anion containing complexes of solvent and cation. Based on the results of that extension, it was determined that cation size and charge density on the cation were critical factors in determining the structure of the acetonitrile anion molecule and in determining if the anion was metalated at the nitrogen or α-carbon position, with larger cations favoring carbon metalation and more significant deformation of the α-carbon from the expected sp2 hybridization. The final aspect of this dissertation was the determination of reaction coordinate energy profiles for a pair of substitution reactions involving nitrile anion containing cycloaliphatic molecules. The results of this study showed that, due to steric and kinetic factors, the axial products and transitions states associated with these reactions were favored, and that the degree of preference was kinetically controlled.
Zeigler, M. (2011). Understanding the Effect of Cation and Solvation on the Structure and Reactivity of Nitrile Anions (Doctoral dissertation, Duquesne University). Retrieved from https://dsc.duq.edu/etd/1404