Date of Graduation

Summer 2014

Degree

Master of Science in Chemistry

Department

Chemistry

Committee Chair

Erich Steinle

Keywords

bifluorenylidene, tetrabenzfulvalene, Lawesson's reagent, thionation, density functional theory, mechanism, sulfur elimination, B3LYP, 6-31G(d), computational, theoretical

Subject Categories

Chemistry

Abstract

Modern theoretical chemistry employs a combination of the analytical and deductive capabilities of the human mind, today's powerful computer systems, and intuitive software applications to peer into the depths of the subatomic. This approach presents a means to improve yields, find new reactions, and reduce costs. Herein, these tools have been employed in a study intended to form a better understanding of the mechanism that allows for the synthesis of bifluorenylidenes from fluorenones. Quantum computations, performed at the B3LYP/6-31G(d) level of theory, were applied to several analog and fluorene-based species to obtain optimized geometries and relative electronic energies of the starting materials, transition states, and proposed cycloadduct intermediates. The energies were used as an indicator toward proposing the initial steps in the reaction, as well as a lens with which to focus the study on later portions of the reaction. The enthalpic data alone was able to eliminate a hypothesized thermal extrusion of diatomic sulfur, based on relative isomeric stability of dithietane rings. Initial thiation of ketones was determined to be probable and several possible pathways have effectively been narrowed by the elimination of six options.

Copyright

© Michael David Nothnagel

Campus Only

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