Date of Award

2021

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

Abstract

Reactivity of molecular solids is governed by topochemical considerations, where minimizedmolecular movement dictates both product identity and kinetics. This Thesis explores the central role reaction cavity plays in the topochemical principle by using the highly varied cavities formed by the different facets of a tetracene crystal. The relative rates for ten different reaction cavities were measured via energy dispersive X-ray spectroscopy for the reaction of tetracene with vapors of maleic anhydride. Variance in cavities resulted in Diels-Alder reaction rates that differed by as much as a factor of 2.6. Effects were understood via molecular dynamic simulations which modeled the approach of the adsorbate and its stabilization within the cavity. For the (110), (11̅0) and (100) facets, kinetics were dictated by sterically hindered access to the reaction cavity which prevented significant residence in the reactive site. For facets where steric hindrance was constant, i.e. the (11̅0), (11̅1) and (11̅1̅) surfaces, the dominant effect was the stabilization of the reactant within the cavity, with the stepped facets positioning the maleic anhydride near the co-planar orientation required by the Diels-Alder transition state.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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