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Conformation of p ‐dimethylamino aza styryl dyes
Author(s) -
Patnaik Lalit N.,
Das Sarojini
Publication year - 1987
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560320506
Subject(s) - benzothiazole , chemistry , quinoline , ring (chemistry) , pyridine , molecule , molecular orbital , computational chemistry , stereochemistry , crystallography , photochemistry , medicinal chemistry , organic chemistry
Conformational studies on some p ‐dimethylamino β‐aza and β‐aza (with respect to the dimethylamino phenyl ring) styryl dyes derived from quinoline‐4, quinoline‐2, pyridine‐4, pyridine‐2, and benzothiazole‐2 have been carried out using the quantum mechanical PCILO (perturbative configuration interaction using localized orbitals) method. These molecules may be considered as heterocyclic analogues of benzylidene anilines whose conformations have been studied extensively by both theoretical and experimental methods to explain the difference of their spectra from the isoelectronic benzylidene compounds. The results of the present studies show that the β‐aza styryl dyes are nearly planar. In case of β‐aza styryl dyes, although the phenyl ring is coplanar with the central atoms, there is a substantial twist of the heterocyclic ring. These results are explained in terms of CT ‐1 and CT ‐2 effects and are used as a possible explanation for the observed spectral and sensitization properties.