The absorption spectra of several phenyl-substituted oxiranes in 3-methylpentane at -196°are highly structured and characterized by a 0-0 band at 271 ± 3 nm with a more intense, structureless band at ~230 nm.The fluorescence emission of these compounds occurs at 285-340 nm, with a maximum at 305-310 nm. The isomeric 2,3-bis-a-naphthyloxiranes and tetraphenylepisulflde have also been studied. Irradiation into the 0-0 or higher energy absorption bands causes formation of a colored intermediate. Subsequently, the parent alkene and arylcarbene(s), and carbonyl compound(s) are formed in a manner dependent on oxirane symmetry. Phenyloxirane behaves atypically and no divalent carbon fragments are formed. A consistent mechanistic pathway is proposed to explain the photochemistry and spectroscopy of the oxiranes and their photoproducts. Several aspects of the spectroscopy and photochemistry of phenyloxiranes have been studied.2 Griffin and coworkers3 have found that arylcarbenes are genii) (a) Taken from the thesis submitted by R. O. B. in partial fulfillment of the Ph.D. requirements
We have applied single determinant ab initio molecular orbital theory to the description of internal rotation in vinylcyclopropane and vinylcyclobutane. Using the minimal STO-3G basis we find the two molecules to be most stable in their s-trans forms but also predict both to possess flat secondary s-cis and gauche minima. Further investigation on vinylcyclopropane with the extended 4-31G basis set confirms the gauche minimum but places doubt on the stability of the s-cis structure. Substitution on the vinyl group in vinylcyclopropane by -
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.