4698-51-5Relevant academic research and scientific papers
Complete 13C and 1H Chemical Shift Assignments for trifluoromethyl-Substituted Naphthylidineanilines: Remote Polar Effects on the Naphthyl ? Electron Distribution
Fernandez-G., Juan M.,Enriquez, Raul G.,Reynolds, William F.,Yu, Margaret
, p. 180 - 181 (1994)
13C and 1H chemical shifts are assigned, using 2D methods, for naphthylidineaniline derivatives with CF3 groups substituted in the phenyl group.The 13C chemical shifts for the naphthalene rings are interpreted in terms of remote ? polarization effects. -
Keto-enol tautomerism of 2-hydroxy naphthylideneaniline with Lanthanide shift reagent Pr(fod)3 in different solvents
Saleem,Sultan
, p. 1189 - 1193 (2013/02/25)
Addition of Lanthanide shift reagents Pr(fod)3 to 2-hydroxynaphthylideneaniline in non polar solvents and slightly polar solvent showed for the first time a keto-enol tautomerism. KT values= ([keto]/[enol]) were calculated in the chosen solvents. KT at fixed con centration of the shift reagent was determined at different temperatures and the thermodynamic parameters (ΔH°, ΔG°, ΔS°) were obtained.
Influence of bond fixation in benzo-annulated N-salicylideneanilines and their ortho-C(=O)X derivatives (X = CH3, NH2, OCH 3) on tautomeric equilibria in solution
Gawinecki, Ryszard,Kuczek, Agnieszka,Kolehmainen, Erkki,Osmialowski, Borys,Krygowski, Tadeusz M.,Kauppinen, Reijo
, p. 5598 - 5607 (2008/02/09)
(Chemical Equation Presented) 1H, 13C, and 15N NMR spectra show that an ortho-C(=O)X group present in the molecules of N-salicylideneanthranilamide (X = NH2), methyl N-salicylideneanthranilate (X = OCH3), N-salicylidene-o- aminoacetophenone (X = CH3), and their benzo analogues have only a minor effect on the tautomeric OH/NH-equilibrium in solution. Only two of three possible tautomers were detected Lability of the absent form was proved by theoretical calculations. Calculated energies show that the enolimino form (OH) is less stable than the enaminone (NH) form only for dibenzo-annulated N-salicylideneanilines. The population of each species in the tautomeric mixture was found to be inversely proportional to its energy. Application of the geometry-based aromaticity index HOMA shows that the effectiveness of the π-electron delocalization in different rings in the molecule depends mostly on the position of benzoannulation. Both the NH...O and N...HO hydrogen bonds present in the NH and OH tautomers respectively, increase the aromaticity of the quasirings H-O-C=C-C=N and O=C-C=C-N-H and decrease the aromatic character of the fused benzene ring. These results seem to be reliable when N-salicylideneanilines studied are compared with naphthalene and their benzo-annulated derivatives i.e., phenanthrene, anthracene, and triphenylene. An analysis of the effectiveness of π-electron delocalization confirms that in all cases studied, the OH form is more stable. Although the HOMA values and calculated energies are not a criterion that allows determination of the dominating tautomer, both of these parameters correctly show the effect of changes in the molecular topology on tautomeric preferences.
