title: Vibrational spectroscopic and DFT study of trimethoprim.
abstract: Structural investigations by different vibrational spectroscopic methods: FTIR, FT-Raman and surface-enhanced Raman scattering (SERS) spectroscopy, as well as density functional theory (DFT) calculations were performed on trimethoprim (5-(3,4,5-trimethoxybenzyl)pyrimidine-2,4-diamine). A reliable assignment of vibrational IR, Raman and SERS bands was possible by a proper choice of model used in quantum chemical calculations. Based on SERS spectrum analysis it is shown that the molecule is adsorbed on the silver surface through the pyrimidine ring, in a perpendicular orientation. Two theoretical models were used in order to simulate the silver surface and the interaction with trimethoprim molecule, the accuracy of the models being evaluated by comparing the predicted bands position of the two complexes with the SERS result.
authors.affiliation: Faculty of Physics, Babeş-Bolyai University, Kogălniceanu 1, 400084 Cluj-Napoca, Romania.
authors.forename: Alia
authors.initials: A
authors.lastname: Ungurean
authors.forename: Nicolae
authors.initials: N
authors.lastname: Leopold
authors.forename: Leontin
authors.initials: L
authors.lastname: David
authors.forename: Vasile
authors.initials: V
authors.lastname: Chiş
mesh_terms: D000327:Adsorption; D000892:Anti-Infective Agents, Urinary / Q000737:chemistry*; D008958:Models, Molecular; D012834:Silver / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D014295:Trimethoprim / Q000737:chemistry*
chemical_list: D000892:Anti-Infective Agents, Urinary; D012834:Silver; D014295:Trimethoprim