Synthesis and Photochemistry of Pyridyl-Based (Trifluoromethyl) Carbenes in Low Temperature Matrices
Loading...
Authors
Groso, Emilia
Issue Date
2013
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
In this study, we examined the photochemical generation of 2- pyridyl(trifluoromethyl)carbene and 3-pyridyl(trifloromethyl)carbene in low-temperature matrices. The carbenes were generated from their previously unknown diazirine precursors, which were synthesized from bromopyridines. The diazirines were each directly deposited on the cesium iodide window of the matrix, and cooled to 10-15K. Once the diazirines were cooled, they were each irradiated with 366nm light. Both of these photolyses were monitored using IR and UVNis spectroscopy. Once we obtained these spectra, we were able to determine the electronic states of the individual carbenes. In order to predict the spin states of the new carbenes, we performed B3LYP/6- 31G** level frequency and time dependent calculations. From these calculations, we were not only able to determine the lowest energy state of the carbenes, but also their theoretical IR and UVNis spectra. We then compared the IR and UVNis spectra obtained from the matrix experiments to the theoretical spectra. From these comparisons, we found that both 2-pyridyl(trifluoromethyl)carbene and 3-pyridyl(trifluoromethyl)carbene are triplet carbenes. The calculations also showed that these triplet states are the lowest energy states of the carbenes. We found that the 2-pyridyl(trifluoromethyl)carbene prefers a conformation such that the trifluoromethyl group is pointed away from the nitrogen; however, the 3-pyridyl(trifluromethyl)carbene showed no such preference.
Description
The University of Nevada, Reno Libraries will promptly respond to removal requests related to content that violates intellectual property laws, data protections, or has been uploaded without creator consent. Takedown notices should be directed to our ScholarWolf team (scholarwolf@library.unr.edu) with information about the object, including its full URL and the nature of your complaint.
Citation
Publisher
License
In Copyright(All Rights Reserved)