A study of several 1,3-cyclobutanediyls by ft-ir and computational techniques

Citation

McKinley, Lindsay K. (1988) A study of several 1,3-cyclobutanediyls by ft-ir and computational techniques. Master's thesis, California Institute of Technology. doi:10.7907/q9v0-5082. https://resolver.caltech.edu/CaltechTHESIS:04062010-131315633

Abstract

We have studied the photolytic decomposition of 2,3-diazabicyclo[2.2.1]hept-2-ene (Closs' azo) by FT-IR spectroscopy. While no transient species were detected, the photolysis product was exclusively bicyclopentane, as compared to Closs' result of 1:30 cyclopentene: bicyclopentane. The reasons for this difference are unclear; it may be due to our choice of argon for a matrix material. It has been previously shown that argon increases ISC rates compared to the first row elements. We have also studied the photolytic decomposition of 1,4-diethy1-2,3-diazabicyclo[2.1.1]hex-2-ene. In this case, we have evidence that an intermediate exists, probably the diazenyl biradical formed by cleavage of a C-N bond. This intermediate has been detected by its decay to the starting diazene with a half-life of roughly 2 min. During the course of this investigation, the 1,4-diethyl diazene has been synthesized using a slight variation of methods previously developed in our group. We have partially redesigned the FT-IR spectrometer in order to facilitate our investigations. Specifically, we have used a lens and mirror system to allow for photolysis inside the spectrometer of compounds deposited on the Displex window. This adaptation greatly reduces the time required for spectral acquisition. Finally, we have undertaken an ab initio study of the biradical 1,3-dietheny1-1,3-cyclobutanediy1 at the Hartree-Fock level. The results of the study show a high concentration of spin density on the ring carbons of the triplet. This difference with experimental results might be ameliorated by an inclusion of configuration interaction, specifically an MCSCF treatment.

Thesis Files