Stereoselective photooxidation of trans-2-butene to epoxide by nitrogen dioxide excited with red light in a cryogenic matrix

Journal Article · Wed Jul 05 04:00:00 EDT 1989 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00196a034· OSTI ID:6946076

Nakata, Munetaka; Frei, H ^[1]

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1. Lawrence Berkeley Lab., CA (USA)

Reaction was induced between trans-2-butene and nitrogen dioxide by exciting trans-2-butene-NO{sub 2} pairs, isolated in solid Ar at red, yellow, and green wavelengths (NO{sub 2}{sup 2}B{sub 2} {l arrow} {anti X}{sup 2}A{sub 1}). The chemistry was monitored by FT-infrared spectroscopy, and Ar ion and cw dye lasers were used for photolysis. Products formed were 2-butene oxide + NO, the former under complete retention of stereochemistry, and an addition product that was identified by {sup 18}O isotopic substitution as a butyl nitrite radical, reported here for the first time. Analysis of the photolysis-wavelength dependence of the butyl nitrite radical and trans-2-butene oxide (NO) growth kinetics revealed that epoxide + NO is formed along two reaction pathways. The first gives trans-2-butene oxide + NO and butyl nitrite radical upon absorption of a single photon by trans-2-butene-NO{sub 2} pairs (one-photon path). The second path is formation of trans-2-butene oxide + NO by photodissociation of trapped butyl nitrite radical by a (second) red or shorter wavelength photon (two-photon path). Two alternative transients are proposed for the one-photon path, namely a hot butyl nitrite radical and an oxirane biradical, respectively. The wavelength dependence of the product branching along the one-photon path indicates that branching occurs from a vibrationally unrelaxed transient. This suggests that the observed stereochemical integrity originates from insufficient coupling of the stretching and bending vibrations of the transient with torsion around its central C-C bond on the time scale of reaction to epoxide + NO and its stabilization as butyl nitrite radical.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6946076
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 111:14; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400000* -- Chemistry
400200 -- Inorganic
Organic
& Physical Chemistry
400500 -- Photochemistry
ALKENES
BUTENES
CHALCOGENIDES
CHEMICAL REACTIONS
CRYOGENICS
DATA
DATA ANALYSIS
DECOMPOSITION
DYE LASERS
EPOXIDES
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
INFRARED SPECTRA
LASERS
LIQUID LASERS
MEASURING INSTRUMENTS
MEASURING METHODS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
SPECTRA