A LFER study of substituent influence on the FTIR and UV spectral data of 2- and 6-substituted nicotinic acidsAuthor(s): Jasmina Nikolic, Gavrilo Sekularac, Vladimir PaviÃÂ¦evic,Dominik Brkic, Sasa Drmanic
The FTIR andUV spectra of the series of 2- and 6-substituted nicotinic acids were determined and the electronic effect of the present substituents and the applied solvents was studied. In order to analyze substituent influence, the FTIR absorption frequencies corresponding to the carbonyl group of the examined compounds were correlated with Hammett equation ï® = ï²ï³ + h, where ï³ is the matching substituent constants for the absorption band of a carbonyl group of the specific compound, and ï² represents the sensitivity of the examined band to substituent effect. Furthermore,UVspectrawere recorded in different solvent and again the absorption frequencies corresponding to the carbonyl group solwere analyzed, this time by Kamlet-Taft equation, in order to quantitatively present solvent influence. The Kamlet-Taft equation is given in the formï®max= ï®0 + sï°* + aï¡+ bï¢ where ï®max is the absorption frequency, ï°* is a measure of the solvent polarity, ï¡ represents the scale of solvent hydrogen bond donor acidities and ï¢ represents the scale of solvent hydrogen bond acceptor basicities.