ABSTRACT
To complement a previous UV study, we present a quantitative evaluation of substituent effects on spectroscopic data ((1)H and (13)C NMR chemical shifts as well as FT-IR absorption frequency) applied to N,N'-bisarylmalonamides, using simple and extended Hammett equations as well as the Swain-Lupton equation. Furthermore, the DFT CAM-B3LYP/6-311+G(d,p) method was applied to study the impact of different solvents on the geometry of the molecules and their spectral data. Additionally, experimental data are correlated with theoretical results; excellent linear dependence was obtained. The overall results presented in this paper show that N,N'-bisarylmalonamides are prominent candidates for model molecules.
ABSTRACT
The UV absorption spectra of ten N,N'-bisarylmalonamides have been recorded in the range 200-400 nm in a set of selected solvents. The solute-solvent interactions have been analyzed on the basis of the linear solvation energy relationship (LSER) concept proposed by Kamlet and Taft. The effects of substituents on the absorption spectra have been interpreted by correlating absorption frequencies with Hammett substituent constants. Furthermore, the experimental findings have been interpreted using the DFT CAM-B3LYP/6-311+G(d,p) method. Electronic energies have been calculated using the same method in combination with the implicit solvation model (conductor-like polarizable continuum model, CPCM) as well as with the explicit addition of two molecules of solvent.
