Photochemistry of matrix-isolated 3-chloro-1,2-benzisoxazole: Generation and characterization of 2-cyanophenoxyl radical and other reactive intermediates

Nunes C. M., Pinto S. M. V., Reva I., Rosado M. T. S., Fausto R.

JOURNAL OF MOLECULAR STRUCTURE, vol.1172, pp.33-41, 2018 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 1172
  • Publication Date: 2018
  • Doi Number: 10.1016/j.molstruc.2017.11.009
  • Journal Name: JOURNAL OF MOLECULAR STRUCTURE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.33-41
  • Istanbul Kültür University Affiliated: Yes

Abstract

Photochemistry of 3-chloro-1,2-benzisoxazole 1 in N-2 and Ar matrices at 10 K leads to N-chloro-ketenimine 3 and 2-cyanophenyl-hypochlorite 4. The reaction kinetics and the observed photoisomerization of 3 to 4 indicate that ketenimine 3, possibly formed via an elusive vinylnitrene VN, is an intermediate in the formation of hypochlorite 4. A new pathway involving the formation of 2-cyanophenoxyl radical 5, which was captured only in Ar matrix, was also observed. Radical 5 is possibly formed via photo detachment of CI atom from I (or VN) and might explain the formation of 3-chloro-6-oxocyclohexa-1,4-dienecarbonitrile 2 in N2 and Ar matrices. All the species were characterized by IR spectroscopy and theoretical calculations. The computed geometric and electronic structure of radical 5 is discussed. Overall, the results provided further insight into the mechanism of the photochemistry of 1,2-benzisoxazoles and allowed characterization of new interesting reactive intermediates. (C) 2017 Elsevier B.V. All rights reserved.