title: Experimental and theoretical studies on vibrational spectra of 4-(2-furanylmethyleneamino)antipyrine, 4-benzylideneaminoantipyrine and 4-cinnamilideneaminoantipyrine.
abstract: This work deals with the IR and Raman spectroscopy of 4-(2-furanylmethyleneamino) antipyrine (FAP), 4-benzylideneaminoantipyrine (BAP) and 4-cinnamilideneaminoantipyrine (CAP) by means of experimental and quantum chemical calculations. The equilibrium geometries, harmonic frequencies, infrared intensities and Raman scattering activities were calculated by density functional B3LYP method with the 6-31G(d) basis set. The comparisons between the calculated and experimental results covering molecular structures, assignments of fundamental vibrational modes and thermodynamic properties were investigated. The optimized molecular geometries have been compared with the experimental data obtained from XRD data, which indicates that the theoretical results agree well with the corresponding experimental values. For the three compounds, comparisons and assignments of the vibrational frequencies indicate that the calculated frequencies are close to the experimental data, and the IR spectra are comparable with some slight differences, whereas the Raman spectra are different clearly and the strongest Raman scattering actives are relative tightly to the molecular conjugative moieties linked through their Schiff base imines. The thermodynamic properties (heat capacities, entropies and enthalpy changes) and their correlations with temperatures were also obtained from the harmonic frequencies of the optimized structures.
authors.affiliation: Key Laboratory of Minstry of Education for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094, PR China. yuxisun@163.com
authors.forename: Yu-Xi
authors.initials: YX
authors.lastname: Sun
authors.forename: Qing-Li
authors.initials: QL
authors.lastname: Hao
authors.forename: Zong-Xue
authors.initials: ZX
authors.lastname: Yu
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Jiang
authors.forename: Lu-De
authors.initials: LD
authors.lastname: Lu
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
mesh_terms: D000983:Antipyrine / Q000031:analogs & derivatives* / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics
chemical_list: D000983:Antipyrine