title: Comprehensive quantum chemical and spectroscopic (FTIR, FT-Raman, 1H, 13C NMR) investigations of O-desmethyltramadol hydrochloride an active metabolite in tramadol--an analgesic drug.
abstract: O-desmethyltramadol is one of the main metabolites of tramadol widely used clinically and has analgesic activity. The FTIR and FT-Raman spectra of O-desmethyl tramadol hydrochloride are recorded in the solid phase in the regions 4000-400 cm(-1) and 4000-100 cm(-1), respectively. The observed fundamentals are assigned to different normal modes of vibration. Theoretical studies have been performed as its hydrochloride salt. The structure of the compound has been optimised with B3LYP method using 6-31G(**) and cc-pVDZ basis sets. The optimised bond length and bond angles are correlated with the X-ray data. The experimental wavenumbers were compared with the scaled vibrational frequencies determined by DFT methods. The IR and Raman intensities are determined with B3LYP method using cc-pVDZ and 6-31G(d,p) basic sets. The total electron density and molecular electrostatic potential surfaces of the molecule are constructed by using B3LYP/cc-pVDZ method to display electrostatic potential (electron+nuclei) distribution. The electronic properties HOMO and LUMO energies were measured. Natural bond orbital analysis of O-desmethyltramadol hydrochloride has been performed to indicate the presence of intramolecular charge transfer. The (1)H and (13)C NMR chemical shifts of the molecule have been anlysed.
authors: Department of Chemistry, Kanchi Mamunivar Centre for Post-Graduate Studies, Puducherry 605 008, India. Electronic address: varjunftir@yahoo.com.
authors: V
authors: V
authors: Arjunan
authors: Research and Development Centre, Bharathiar University, Coimbatore 641 046, India.
authors: R
authors: R
authors: Santhanam
authors: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw 2, Poland.
authors: M K
authors: MK
authors: Marchewka
authors: School of Sciences and Humanities, Vel Tech University, Avadi, Chennai 600 062, India.
authors: S
authors: S
authors: Mohan
mesh_terms: D000700:Analgesics / Q000737:chemistry* / Q000378:metabolism*; D066241:Carbon-13 Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D066244:Proton Magnetic Resonance Spectroscopy; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013816:Thermodynamics; D014147:Tramadol / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D014732:Vibration
chemical_list: D000700:Analgesics; C080580:O-demethyltramadol; D014147:Tramadol
keywords: DFT; FT-Raman; FTIR; NBO; NMR; O-desmethyltramadol hydrochloride