Fourier transform mass spectrometric generation and studies of carboethoxycarbene anion radical (EtOCOCH sup sm bullet minus )

Journal Article · Wed Apr 26 04:00:00 EDT 1989 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00191a006· OSTI ID:5041047

Chowdhury, A K; Wilkins, C L ^[1]

---

1. Univ. of California, Riverside (USA)

In contrast to results from flowing afterglow studies, electron attachment with ethyl diazoacetate in a Fourier transform mass spectrometer produces abundant carboethoxycarbene anion radical, EtOCOCH{sup {sm bullet}{minus}}. Upon collision-induced dissociation, EtOCOCH{sup {sm bullet}{minus}} appears to eliminate C{sub 2}H{sub 4} via a six-membered transition state yielding an ion with m/z 58. Two resonance structures, a carbon-centered radical anion (I) and an oxygen-centered anion (II), can be considered in order to understand the reactivity of EtOCOCH{sup {sm bullet}{minus}}. Reactions of EtOCOCH{sup {sm bullet}{minus}} with carbonyl compounds and activated olefins can be rationalized by considering the carbon-centered radical anion (I) to make a greater contribution. With use of the bracketing method, the proton affinity of EtOCOCH{sup {sm bullet}{minus}} is determined to be 377.2 {plus minus} 2 kcal/mol, from which {Delta}H{sub f}(EtOCOCH{sup {sm bullet}{minus}}) = {minus}48.5 {plus minus} 3 kcal/mol was calculated. As a free radical, EtOCOCH{sup {sm bullet}{minus}} abstracts H{sup {sm bullet}} atom donors. Using such reactions to bracket the hydrogen dissociation energy yields an estimate of D(EtOCOCH{sup {minus}}H) {>=} 101 {plus minus} 1 kcal/mol.

• OSTI ID: 5041047
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 111:9; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ALKOXY RADICALS
ANIONS
CARBENES
CHARGED PARTICLES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
DATA
DECOMPOSITION
DIAZO COMPOUNDS
ETHOXY RADICALS
EXPERIMENTAL DATA
FOURIER TRANSFORM SPECTROMETERS
INFORMATION
IONS
MASS SPECTROSCOPY
MEASURING INSTRUMENTS
MOLECULAR STRUCTURE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADICALS
RESONANCE
SPECTROMETERS
SPECTROSCOPY
SYNTHESIS