Aroylnitrenes with singlet ground states: photochemistry of acetyl-substituted aroyl and aryloxycarbonyl azides

Journal Article · Wed Jun 22 00:00:00 EDT 1988 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00221a032· OSTI ID:6186179

Sigman, M E; Autrey, T; Schuster, G B

The photochemistry of 4-acetylbenzoyl azide (ABA), 4-acetyl-4'-biphenoyl azide (ADA), and 4-acetylphenoxycarbonyl azide (APA) shows unusual wavelength and structural effects. Irradiation of ABA or ADA into their ..pi..-..pi..* bands with deep-UV light leads to formation of 4-acetylbenzoylnitrene (ABN) and 4-acetyl-4'-biphenoylnitrene (ADN), respectively, in competition with photo-Curtius rearrangement to form isocyanates. Irradiation of these azides into their n-..pi..* bands with near-UV light gives only the aroylnitrenes. The triplet excited states of the azides were detected chemically and by transient spectroscopic techniques. Nitrogen loss following near-UV irradiation occurs exclusively from the excited triplet azides. However, the chemical properties of ABN and ADN are consistent only with reactions originating from their singlet states. An ESR spectrum is observed at 8 K for ((4-acetylphenoxy)carbonyl) nitrene (APN) but not for 4-acetylbenzoylnitrene (ABN) or 4-acetyl-4'-biphenylcarbonylnitrene (ADN). The chemical properties of APN in tert-butyl alcohol show that its triplet is no more than 5 kcal/mol below its lowest single state. In contrast, the chemical properties of ABN and ADN indicate that these nitrenes have singlet ground states.

• Research Organization: Univ. of Illinois, Urbana (USA)
• OSTI ID: 6186179
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 110:13
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AZIDO COMPOUNDS
PHOTOCHEMISTRY
CARBONYLS
ORGANIC NITROGEN COMPOUNDS
GROUND STATES
ELECTRON SPIN RESONANCE
EXCITED STATES
EXPERIMENTAL DATA
MOLECULAR STRUCTURE
PHOTOCHEMICAL REACTIONS
STRUCTURAL CHEMICAL ANALYSIS
CHEMICAL REACTIONS
CHEMISTRY
DATA
ENERGY LEVELS
INFORMATION
MAGNETIC RESONANCE
NUMERICAL DATA
ORGANIC COMPOUNDS
RESONANCE
400500* - Photochemistry