Synthesis, spectroscopic and computational characterization of the tautomerism of pyrazoline derivatives from chalcones

摘要: In the present study a series of novel pyrazolines derivatives has been synthesized, and their structures assigned on basis FT-Raman, (1)H (13)C NMR spectral data computational DFT calculations. A joint using B3LYP/6-311G(2d,2p) density functional theory FT-Raman investigation tautomerism 3-(4-substituted-phenyl)-4,5-dihydro-5-(4-substituted-phenyl)pyrazole-1-carbothioamide 3-(4-substituted-phenyl)-4,5-dihydro-5-(4-substituted-phenyl)pyrazole-1-carboxamide are presented. The were characterized as minimum in potential energy surface DFT. calculated Raman spectra such remarkable agreement to experimental results that equilibrium between tautomeric forms discussed detail. Our suggests existence tautomers, carboxamide/carbothioamide group may tautomerize, solid state or solution. Thermodynamic R(CS)NH2 R(CO)NH2 species more stable than R(CNH)SH R(CNH)OH species. Additionally, found for shifting, pointed out which structure is present.