Hydrogen-Bonded Pyridine−Water Complexes Studied by Density Functional Theory and Raman Spectroscopy

Autor: Ranjan K. Singh, B.P. Asthana, S. Schlücker, J. Popp, Wolfgang Kiefer
Rok vydání: 2001
Předmět:
Zdroj: The Journal of Physical Chemistry A. 105:9983-9989
ISSN: 1520-5215
1089-5639
DOI: 10.1021/jp0122272
Popis: Density functional theory (DFT) at the B3LYP/6-31++G(d,p) level was employed to obtain the optimized geometries and vibrational spectra of several pyridine(Py)−water(W) complexes with stoichiometric ratios ranging from 2:1 (Py2W) to 1:3 (PyW3). The harmonic vibrational wavenumbers of pyridine ring modes and the fundamental modes of water were calculated in order to examine the influence of hydrogen bonding on the normal modes of both pyridine and water upon complexation. The Raman spectra in the wavenumber region 960−1060 cm-1 covering the ring modes ν1 and ν12 of pyridine (in Wilson's notation) as a function of pyridine mole fraction were recorded. The integrated Raman intensities in the isotropic components of the spectra were used to determine the relative concentration of “free” pyridine molecules in close neighborhood with other Py−W complexes. The combination of both experimental wavenumbers yielding the overall shift induced by the entirety of hydrogen-bonded complexes in the mixture and the DFT-de...
Databáze: OpenAIRE