T. Baul, P. Das, A. K. Chandra
Sep 1, 2009
Citations
0
Influential Citations
25
Citations
Journal
Dyes and Pigments
Abstract
Abstract The structures of several azo-benzoic acids, 4-[(( E )-1-{2-hydroxy-5-[( E )-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoic acid along with their precursors 2-hydroxy-5-[( E )-(aryldiazenyl)]benzaldehydes were confirmed using 1 H, 13 C NMR, UV–VIS and IR spectroscopic techniques. UV–VIS absorption spectra were measured in pure organic solvents while complementary spectroscopic experiments using mixed solvent systems as well as in the presence of base were undertaken to characterize the different species present in solution. Both acid–base dissociation and azo–hydrazone tautomerism occurred in solution, with the extent of the individual equilibria being dependent on the solvent composition and/or pH of the medium. Molecular structures and geometries were optimized using the B3LYP density functional theory method employing the 6-31G(d) basis set.