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[摘要]：The photochem. of 6-bromo-2-naphthols has been studied in acetonitrile, aq. acetonitrile, and iso-Pr alc. in the absence and in the presence of triethylamine by product distribution anal., laser flash photolysis (LFP), fluorescence, phosphorescence, electrochem. measurements, and DFT calcns. Hydrobromic acid loss in the presence of Et3N occurs from the triplet state of 6-bromo-2-naphthol, generating an electrophilic carbene intermediate, which has been successfully trapped by oxygen, allyltrimethylsilane, 2,3-dimethylbut-2-ene, pyrrole, acrylonitrile, 1,4-dimethoxybenzene, and also pyridine. The generation and the reactivity of a triplet carbene intermediate has been supported by LFP, with the detection of 2,6-naphthoquinone-O-oxide (530 < l < 650 nm) in the presence of O2. The electrophilic diradical character of the carbene has been supported by DFT calcns., using the B3LYP, PBE0, and MPWB1K functionals, with the 6-31+G(d,p) basis set and PCM solvation model. |
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