Open AccessSubstituent effect on IR, 1H and 13C NMR spectral data in n-(substituted phenyl)-2-cyanoacetamides: A correlation study
Author(s) -
Aleksandar D. Marinković,
Dominik Brkić,
Jelena S. Martinović,
Dušan Ž. Mijin,
Miloš K. Milčić,
Slobodan Petrović
Publication year - 2013
Publication title -
chemical industry and chemical engineering quarterly
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.189
H-Index - 26
eISSN - 2217-7434
pISSN - 1451-9372
DOI - 10.2298/ciceq120109044m
Subject(s) - substituent , chemistry , taft equation , carbon 13 nmr , delocalized electron , chemical shift , resonance (particle physics) , electrophile , proton nmr , electronic effect , computational chemistry , hammett equation , stereochemistry , organic chemistry , reaction rate constant , kinetics , physics , particle physics , quantum mechanics , steric effects , catalysis
Linear free energy relationships (LFER) were applied to the IR, 1H and 13C NMR spectral data of N-(substituted phenyl)-2-cyanoacetamides. A variety of substituents were employed for phenyl substitution and fairly good correlations were obtained using the simple Hammett and the Hammett-Taft dual substituent parameter equations. The correlation results of the substituent induced 13C NMR chemical shifts (SCS) of the C1, C=O and N-H atom indicated different sensitivity with respect to electronic substituent effects. A better correlation of the SCSC=O with a combination of electrophilic and nucleophilic substituent constants indicated a significant contribution of extended resonance interaction (π-delocalization) within the π1-unit. The conformations of the investigated compounds were studied using the DFT B3LYP/6-311G method and, together with the results of 13C NMR and IR spectroscopic studies, a better insight into the influence of such a structure on the transmission of electronic substituent effects was obtained