title: Vibrational spectroscopic study of o-, m- and p-hydroxybenzylideneaminoantipyrines.
abstract: Three structurally similar antipyrine derivatives of o-hydroxybenzylideneaminoantipyrine (o-HBAP), m-hydroxybenzylideneaminoantipyrine (m-HBAP) and p-hydroxybenzylideneaminoantipyrine (p-HBAP) were characterized by FT-IR, FT-Raman experimental techniques and density functional theoretical (DFT) calculations. 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 agree well with the corresponding experimental values by comparing with the XRD data. The comparisons and assignments of the vibrational frequencies indicate that the experimental spectra also coincide satisfactorily with those of theoretically simulated spectrograms except the hydrogen-bond coupling infrared vibrations, and compounds can be distinguished by the IR and Raman spectra due to the differences of the hydroxyl-substituted positions and molecular packing, and the strong Raman scattering activities of the compounds are tightly relative to the molecular conjugative moieties linked through the Schiff base imines. The thermodynamic functions and their correlations with temperatures were also obtained from the theoretical harmonic frequencies.
authors.affiliation: Key Laboratory of Education Ministry for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing, 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: Lu-De
authors.initials: LD
authors.lastname: Lu
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Xu-Jie
authors.initials: XJ
authors.lastname: Yang
mesh_terms: D000983:Antipyrine / Q000737:chemistry*; D008962:Models, Theoretical; D015394:Molecular Structure; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000379:methods; D013816:Thermodynamics; D014732:Vibration
chemical_list: D000983:Antipyrine