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Study of carvedilol by combined Raman spectroscopy and ab initio MO calculations
Author(s) -
Marques M. P. M.,
Oliveira P. J.,
Moreno A. J. M.,
Batista de Carvalho L. A. E.
Publication year - 2002
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.916
Subject(s) - chemistry , raman spectroscopy , ab initio , carbazole , molecule , titration , density functional theory , amine gas treating , computational chemistry , carvedilol , analytical chemistry (journal) , organic chemistry , medicine , heart failure , physics , optics
The novel cardioprotective drug carvedilol was studied by both Raman spectroscopy and ab initio molecular orbital methods (using the density functional theory approach). The spectra, acquired both for the solid samples and DMSO solutions as a function of pH, were assigned in view of the calculated wavenumbers and intensities, and also based on the experimental data obtained for individual compounds which comprise the molecule, namely carbazole and 1,2‐dimethoxybenzene. The pH dependence of the Raman pattern of carvedilol was studied, and the p K a value of its secondary amine group was determined (p K a = 8.25) through pH titration experiments. This kind of information is of great significance for the understanding of the biochemical role of carvedilol, which is strongly determined by the acid–base behaviour of the molecule. Copyright © 2002 John Wiley & Sons, Ltd.