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https://hdl.handle.net/10316/101239
Título: | UV-Induced Photochemistry of 1,3-Benzoxazole, 2-Isocyanophenol, and 2-Cyanophenol Isolated in Low-Temperature Ar Matrixes | Autor: | Reva, Igor Jesus, A. J. Lopes Nunes, Cláudio M Roque, José P. L. Fausto, Rui |
Data: | 2021 | Editora: | American Chemical Society | Projeto: | info:eu-repo/grantAgreement/POCI-01-0145-FEDER-028973/PT UIDB/00313/2020 UIDB/00102/2020 UIDP/00313/2020 UIDP/00102/2020 |
Título da revista, periódico, livro ou evento: | The Journal of Organic Chemistry | Volume: | 86 | Número: | 9 | Resumo: | The monomers of 1,3-benzoxazole isolated in a cryogenic argon matrix were characterized by infrared spectroscopy. The photochemistry of matrix-isolated 1,3-benzoxazole, induced by excitation with a frequency-tunable narrowband UV light, was investigated. Irradiation at 233 nm resulted in a nearly quantitative conversion of 1,3-benzoxazole into 2-isocyanophenol. The individual photochemical behavior of the in situ produced 2-isocyanophenol was studied upon excitations at 290 nm, where 1,3-benzoxazole does not react. The photochemistry of isomeric matrix-isolated 2-cyanophenol was also studied. The photoreactions of 2-substituted (cyano- or isocyano-) phenols were found to have many similarities: (i) OH bond cleavage, yielding a 2-substituted (cyano- or isocyano-) phenoxyl radical and an H-atom, (ii) recombination of the detached H-atom, resulting in an oxo tautomer, and (iii) decomposition leading to fulvenone, together with HCN and HNC. In another photoprocess, 2-cyanophenol undergoes a [1,5] H-shift from the hydroxyl group to the cyano group yielding isomeric ketenimine. The analogous [1,5] H-shift from the hydroxyl group to the isocyano group must have also occurred in 2-isocyanophenol; however, the resulting nitrile ylide isomer is kinetically unstable and collapses to benzoxazole. All photoproducts were characterized by comparing their observed infrared spectra with those computed at the B3LYP/6-311++G(d,p) level. The mechanistic analysis of the photochemistry occurring in the family of the title compounds is presented. | URI: | https://hdl.handle.net/10316/101239 | ISSN: | 0022-3263 1520-6904 |
DOI: | 10.1021/acs.joc.0c02970 | Direitos: | embargoedAccess |
Aparece nas coleções: | I&D CQC - Artigos em Revistas Internacionais |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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JOC-2021-86-6126.pdf | 1.55 MB | Adobe PDF | Ver/Abrir |
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