MOLECULAR-STRUCTURE AND INFRARED-SPECTRA OF 2-HYDROXY-1,4-NAPHTHOQUINONE - EXPERIMENTAL MATRIX-ISOLATION AND THEORETICAL HARTREE-FOCK AND POST-HARTREE-FOCK STUDY

The infrared spectra of 2-hydroxy-1,4-naphthoquinone (HNQ) isolated in low-temperature Ar and N-2 matrices are reported. The calculations of electronic energies for possible tautomers of HNQ (performed at RHF/6 -31 + + G* and MP2/6-31 + + G** levels of theory) and the comparison of the experimental spectra with those theoretically calculated (at th e RHF/6-31 + + G* and DFT(B3-LYP)/6-31 + + G** levels) show that the molecules of the compound isolated in low-temperature matrices exist i n the form with intramolecular hydrogen bond. Theoretical results repr oduce well the experimental infrared spectra of the matrix isolated HN Q. The assignment of the infrared absorption bands due to monomers of the compound isolated in Ar and N-2 matrices to the theoretically pred icted normal modes is presented. (C) 1998 Elsevier Science B.V. All ri ghts reserved.