A CCSD(T) and DFT investigation of m-benzyne and 4-hydroxy-m-benzyne

4-Hydroxy-m-benzyne (2a), which is interesting in connection with research on enediyne antitumor drugs, has been identified by comparing the measured infrared spectrum with vibrational spectra calculated at the CCSD(T)/6–31G(d,p) and B3LYP/6–31G(d,p) levels of theory. Although the vibrational spectra calph bands that make an identification of 2a in the matrix at low temperatures possible. Molecule 2a possesses the structure of a σ-biradical. Its isomer bicyclo[3.1.0]hexatriene is not stable, which is parallel to the result obtained for the parent molecule m-benzyne (1). The biradical character of 2a is somewhat lower than that of 1.