Direct Observation of Carbamoylnitrenes.
As the prototype Curtius rearrangement reaction, carbamoyl azide decomposes into aminoisocyanate and molecular nitrogen. However, the key intermediate carbamoylnitrene was previously undetected, even though the decomposition of carbamoyl azides has been studied frequently since its discovery in the 1890s. Upon ArF laser (λ=193 nm) photolysis, the stepwise decomposition of the two simplest carbamoyl azides H2 NC(O)N3 and Me2 NC(O)N3, isolated in solid noble gas matrices, occurs with the formation of the corresponding carbamoylnitrenes H2 NC(O)N and Me2 NC(O)N. Both triplet species are characterized for the first time by combining matrix-isolation IR spectroscopy and quantum-chemical calculations. Subsequent visible-light irradiations cause efficient rearrangement of these nitrenes into the respective aminoisocyanates.
The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China.
Hongmin
H
Li
The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China.
Huabin
H
Wan
The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China.
Zhuang
Z
Wu
The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China.
Dingqing
D
Li
Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux (IPREM), Université de Pau et des Pays de l'Adour, 64000, Pau, France.
Didier
D
Bégué
School of Chemistry and Molecular Biosciences, The University of Queensland, 4072, Brisbane, Queensland, Australia. wentrup@uq.edu.au.
Curt
C
Wentrup
The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China. xqzeng@suda.edu.cn.
Xiaoqing
X
Zeng
Curtius rearrangement; IR spectroscopy; azides; matrix isolation; nitrenes