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Photochemistry of Phenyl Azides Bearing 2‐Hydroxy and 2‐Amino Groups Studied by Matrix‐Isolation Spectroscopy: Generation and Characterization of Reactive o ‐Quinoid Compounds
Author(s) -
Tomioka Hideo,
Matsushita Takeshi,
Murata Shigeru,
Koseki Shiro
Publication year - 1996
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199619961206
Subject(s) - chemistry , matrix isolation , azide , infrared spectroscopy , irradiation , absorption (acoustics) , spectroscopy , absorption spectroscopy , photochemistry , double bond , ab initio , medicinal chemistry , crystallography , polymer chemistry , organic chemistry , physics , quantum mechanics , nuclear physics , acoustics
Broad‐band irradiation (λ > 370 nm) of 2‐hydroxyphenyl azide ( 1 ) in Ar at 10K monitored by IR resulted in the formation of at least three major products, all of which were shown to be photointerconvertible under these conditions. The two products showing carbonyl stretching absorption bands were assigned to an E/Z mixture of 6‐imino‐2,4‐cyclohexadien‐1‐one ( 3 ), while the product showing sharp absorption bands in the cumulenic double bond region was assigned to 6‐imino‐1,3,5‐hexatrien‐1‐one ( 4 ). These assignments were fully supported by comparison of the experimental IR spectra with the theoretical data calculated at the HF/6‐31G ** level of theory. Similar irradiation (λ > 350 nm) of 2‐aminophenyl azide ( 6 ) in Ar at 10 K also afforded three photointerconvertible products, which were assigned to a mixture of ( E,E )‐( E,Z )‐ and ( Z,Z )‐1,2‐diimino‐3,5‐cyclohexadiene ( 8 ). The assignments were again supported by ab initio calculations. The reactions are discussed in terms of a 1,4 H shift in the photolytically generated phenylnitrenes ( 2 and 8 ) from the azides ( 1 and 7 ).