The Products and Mechanisms of the Cyclization of Conjugated Polyenes After AirFree Protonation with Trifluoroacetic Acid
Date of Award
5-5-2024
Degree Name
M.S. in Chemistry
Department
Department of Chemistry
Advisor/Chair
Justin Biffinger
Abstract
Linear polyenes are a class of compounds containing two or more alternating carbon-carbon double and single bonds that have a range of applications from antioxidants in nature to non-linear optical switches. More recently, other related π conjugated systems (like cinnamaldehyde) with heteroatoms within the π-conjugation are being used as chemical additives in fracturing fluids (or “fracking”) in our continued exploration of crude oil. Though this class of chemicals is considered non-hazardous, they are susceptible to oxidative additions initiated with a free radical oxidant. Because of their relative insolubility in water and high solubility in non-polar solvents, the protonation of conjugated polyenes represents a potential pathway to create novel cyclic conjugated structures in one step or hazardous products in the environment. I will present a systematic approach to analyzing the numerous products from the reaction of linear polyenes with trifluoroacetic acid under Airfree conditions to compare to the relative product distributions. The data generated in this project also provides insight into the relative stability of carbocation intermediates that are potentially created. Based on the structure of the products, we will propose mechanisms for the resulting reactions based on multivariate spectroscopic data sets. Some of the spectroscopic techniques include 1D and 2D NMR, UV-vis spectroscopy, fluorescence spectroscopy, and Mass Spectroscopy. The products that were isolated thus far indicate that inter- and intramolecular cyclization are occurring after the protonation of the polyene occurs.
Keywords
1D and 2D NMR, UV-vis spectroscopy, fluorescence spectroscopy, Mass Spectroscopy, protonation of polyenes, cyclization of conjugated polyenes, cinnamaldehyde, DPH, (1, 6-diphenyl-1, 3, 5-hexatriene)
Rights Statement
Copyright 2024, author
Recommended Citation
Gomez, Christopher Andrew, "The Products and Mechanisms of the Cyclization of Conjugated Polyenes After AirFree Protonation with Trifluoroacetic Acid" (2024). Graduate Theses and Dissertations. 7583.
https://ecommons.udayton.edu/graduate_theses/7583
