Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Webster, Charles Edwin

Committee Member

Smith, Dennis W., Jr.

Date of Degree

8-10-2018

Document Type

Dissertation - Open Access

Major

Chemistry

Degree Name

Doctor of Philosophy

College

College of Arts and Sciences

Department

Department of Chemistry

Abstract

As a reliable, convenient, and advantageous tool in the theoretical investigations of bioorganic, inorganic, and organometallic chemistry, density functional theory (DFT) computations have provided chemists with numerous significant insights. The understanding of mechanisms of chemical reactions, and the design and development of catalysts have been greatly promoted by the employment of DFT. In this dissertation, the applications of DFT computations in the catalytic bioorganic, inorganic, and organometallic systems were studied. Phosphoramidate hydrolysis catalyzed by human histidine triad nucleotide binding protein 1 (hHint1) was investigated using a cluster-model DFT approach, and the key involvement of the histidine triad as a proton shuttle was discussed in the proposed mechanism. The IEFPCM-Bondi-B3LYP/BS1 methodology was demonstrated as a reliable, and time-saving model in computing the reduction potentials of transition metal complexes. Moderate accuracy (MAD = 0.233 V, mean absolute deviation) and good linear correlation (R2 = 0.93) between computed and experimental reduction potentials of the 49 studied species are osberved. The fluxionality of cyclohexenyl manganese tricarbonyl [(C6H9)Mn(CO)3] was investigated using DFT computations, which uncovered a previously uncharacterized “closed” Cs agostomer. The intramolecular oxidative amination of an alkene catalyzed by the extreme π-loading N-heterocyclic carbene pincer Tantalum(V) bis(imido) complex was also computationally analyzed, and the mechanisms of the formation of oxidative amination product, reduction product, and hydroamination product were investigated. The computational results are consistent with the experimentally observed product ratios and selectivity.

URI

https://hdl.handle.net/11668/20994

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