title: The molecular structure and vibrational, (1)H and (13)C NMR spectra of lidocaine hydrochloride monohydrate.
abstract: The structure, vibrational and NMR spectra of the local anesthetic drug lidocaine hydrochloride monohydrate salt were investigated by B3LYP/6-311G(∗∗) calculations. The lidocaine·HCl·H2O salt is predicted to have the gauche structure as the predominant form at ambient temperature with NCCN and CNCC torsional angles of 110° and -123° as compared to 10° and -64°, respectively in the base lidocaine. The repulsive interaction between the two N-H bonds destabilized the gauche structure of lidocaine·HCl·H2O salt. The analysis of the observed vibrational spectra is consistent with the presence of the lidocaine salt in only one gauche conformation at room temperature. The (1)H and (13)C NMR spectra of lidocaine·HCl·H2O were interpreted by experimental and DFT calculated chemical shifts of the lidocaine salt. The RMSD between experimental and theoretical (1)H and (13)C chemical shifts for lidocaine·HCl·H2O is 2.32 and 8.21ppm, respectively.
authors.affiliation: Department of Chemistry, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran 31261, Saudi Arabia. Electronic address: hbadawi@kfupm.edu.sa.
authors.forename: Hassan M
authors.initials: HM
authors.lastname: Badawi
authors.affiliation: Department of Chemistry, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Förner
authors.affiliation: Department of Chemistry, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
authors.forename: Shaikh A
authors.initials: SA
authors.lastname: Ali
mesh_terms: D000779:Anesthetics, Local / Q000737:chemistry*; D008012:Lidocaine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D014867:Water / Q000737:chemistry
chemical_list: D000779:Anesthetics, Local; D014867:Water; D008012:Lidocaine
keywords: (1)H and (13)C NMR spectra and assignments; Lidocaine hydrochloride monohydrate; Local anesthetic drug; Molecular structure; Vibrational