Get access

DFT computational studies on rotation barriers, tautomerism, intramolecular hydrogen bond, and solvent effects in 8-hydroxyquinoline

Authors

  • Andrew E. Shchavlev,

    1. Division of Computational and Informational Science, Volga Region Academy of State Service, 23/25 Sobornaya Street, Saratov 410031, Russia
    Search for more papers by this author
  • Alexei N. Pankratov,

    Corresponding author
    1. Department of Chemistry, N. G. Chernyshevskii Saratov State University, 83 Astrakhanskaya Street, Saratov 410012, Russia
    • Department of Chemistry, N. G. Chernyshevskii Saratov State University, 83 Astrakhanskaya Street, Saratov 410012, Russia
    Search for more papers by this author
  • Alexei V. Shalabay

    1. Department of Chemistry, N. G. Chernyshevskii Saratov State University, 83 Astrakhanskaya Street, Saratov 410012, Russia
    Search for more papers by this author

Abstract

Intramolecular hydrogen binding interactions in 8-hydroxyquinoline, both in its zwitterionic tautomer and in the rotamer without the intramolecular hydrogen bond (IHB), have been computed using the B3LYP and MPW1K density functionals. The rotation of the O[BOND]H bond and intramolecular proton transfer reactions were studied theoretically. The following theory levels have been applied: B3LYP/6-31G(d,p), B3LYP/6-311++G(d,p), MPW1K/6-311++G(d,p), and MPW1K/6-311++G(2d,3p)//MPW1K/6-311++G(d,p). Natural bond orbital (NBO) analysis has also been carried out. The effect of medium (benzene, chloroform, tetrahydrofuran, 1,2-dichloroethane, acetone, water) was simulated using the self-consistent reaction field (SCRF) method within the framework of the polarizable continuum model (PCM), at the MPW1K/6-311++G(d,p) level. The evolution of geometry, relative energies, heights of rotation (around the O[BOND]H bond) and tautomerization barriers, IHB energies, and ΔG(solv) have been systematically investigated. The results obtained have shown the failure to neglect some changes of the above characteristics in polar media with respect to the gaseous phase. The series of stability of the forms under study in the gaseous phase remains the same in solution. Thus, in spite of the important role of the solvent electrostatic effects, the intrinsic stability of those species overcomes the solvent effects. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006

Get access to the full text of this article

Ancillary