Molecular dynamics modeling in quantum chemical calculations. Optical absorption spectra of 1,3-Dimethyl-1H-Pyrazolo[3,4-b]quinoline derivatives

Paper presents the quantum chemical modeling of the optical absorption spectra of 6-fluoro, 6-bromo, 7-trifluoromethyl, 6-cyano and 6-carboethoxy derivatives of 1,3-Dimethyl-1H-Pyrazolo[3,4-b]quinoline. The calculations are performed by means of the semiempirical quantum chemical methods (AM1 or PM3...

Full description

Saved in:
Bibliographic Details
Published in:Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2008-10, Vol.70 (5), p.1097-1103
Main Authors: Koścień, E, Gondek, E, Kityk, A V
Format: Article
Language:English
Subjects:
Models, Chemical
Models, Molecular
Molecular Conformation
Molecular Structure
Pyrazoles - chemistry
Quantum Theory
Quinolines - chemistry
Spectrophotometry
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Paper presents the quantum chemical modeling of the optical absorption spectra of 6-fluoro, 6-bromo, 7-trifluoromethyl, 6-cyano and 6-carboethoxy derivatives of 1,3-Dimethyl-1H-Pyrazolo[3,4-b]quinoline. The calculations are performed by means of the semiempirical quantum chemical methods (AM1 or PM3) in combination with molecular dynamics (MD) simulations at T=300 K. It is shown that a particular rotational dynamics of the methyl, trifluoromethyl or ethyl groups practically does not influence the optical absorption in the spectral range 200-500 nm whereas broadening of absorption bands may be well reproduced within MD simulations including all types of nuclei vibrations. The results of calculations are compared with the measured spectra of optical absorption. The quantum chemical method AM1 in combination with MD simulations gives for all dyes the best agreement between the calculated and measured spectral positions of the first absorption band (absorption threshold).
ISSN:1386-1425
DOI:10.1016/j.saa.2007.10.020