Theoretical studies of 2-quinolinol: Geometries, vibrationalfrequencies, isomerization, tautomerism, and excited states
Résumé
tWe treat theoretically 2-quinolinol(lactam), an analog of carbostyril and DNA bases. We characterized theground state structure of 2-quinolinol and its isomer(lactim) using density functional theory(DFT). Thereaction profile and energetics for lactam–lactim tautomerization and cis-lactim to trans-lactim isomer-ization predicted with explicitly correlated methods. We explored the pattern of the lowest singlet andtriplet manifolds of states and electronic S1← S0transitions using multiconfigurational methodologies.The theoretical results are compared with available experimental data and used to interpret the on-goingphotoelectron study of 2-quinolinol. Our analysis should help to understand the effect of tautomerismand aromaticity on the DNA bases.