title: Surface enhancement Raman scattering of tautomeric thiobarbituric acid. Natural bond orbitals and B3LYP/6-311+G (d, p) assignments of the Fourier Infrared and Fourier Raman Spectra.
abstract: Surface enhancement Raman scattering (SERS) of two tautomer of thiobarbituric acid was obtained using silver and gold nanoparticles. Large band enhancement in the region of the ν(C=S), ν(C=C), δ(CH2), and δ(CNH) vibrational modes was found. Natural bond analysis of the tautomer species revealed expressive values of charge transfer, principally from lone pair electron orbitals of the S, N, and O atoms. Complete vibrational assignment was done for the two tautomers using the B3LYP/6-311+G (d, p) procedure, band deconvolution analysis, and from a rigorous interpretation of the normal modes matrix. The calculated spectra agree well with the experimental ones.
authors.affiliation: Laboratory of Biomedical Vibrational Spectroscopy, IP&D, Research and Development Institute-UNIVAP, Urbanova, São José dos Campos, SP, Brazil. tellez@vm.uff.br
authors.forename: C A Téllez
authors.initials: CA
authors.lastname: Soto
authors.forename: J M
authors.initials: JM
authors.lastname: Ramos
authors.forename: A C
authors.initials: AC
authors.lastname: Costa Junior
authors.forename: Laís S
authors.initials: LS
authors.lastname: Vieira
authors.forename: João L
authors.initials: JL
authors.lastname: Rangel
authors.forename: L
authors.initials: L
authors.lastname: Raniero
authors.forename: Priscila P
authors.initials: PP
authors.lastname: Fávero
authors.forename: Tibebe
authors.initials: T
authors.lastname: Lemma
authors.forename: Grisset F
authors.initials: GF
authors.lastname: Ondar
authors.forename: Otavio
authors.initials: O
authors.lastname: Versiane
authors.forename: A A
authors.initials: AA
authors.lastname: Martin
mesh_terms: D008958:Models, Molecular; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013237:Stereoisomerism; D013858:Thiobarbiturates / Q000737:chemistry*
chemical_list: D013858:Thiobarbiturates; C029684:thiobarbituric acid
keywords: FT-Raman; FT-infrared; Natural bond analysis; SERS spectrum; Thiobarbituric acid