title: Conformational study and reassessment of the vibrational assignments for Norspermidine.
abstract: The present study presents and discusses the conformational preferences of Norspermidine (NSpd). The effects of varying the dielectric constant on the conformational preferences are discussed, with a view to infer which conformation will correspond to the most stable in the pure condensed liquid phase. Within the same context, a set of NSpd-NH3 molecular adducts were simulated in order to determine the relevance of intermolecular hydrogen bonding on the overall stability and relative positioning of the respective vibrational frequencies. The calculations presently performed allowed a reassessment of the vibrational assignments for NSpd. A full assignment of the NSpd vibrational spectra is presented, with special emphasis being given to the vibrational modes that proved to be most affected by hydrogen bonding. The various inconsistencies of a prior study found in the literature were identified and rectified.
authors.affiliation: I&D Unit "Química-Física Molecular", Department of Chemistry, Faculty of Science and Technology, University of Coimbra, P-3004-535 Coimbra, Portugal.
authors.forename: T M
authors.initials: TM
authors.lastname: Silva
authors.affiliation: I&D Unit "Química-Física Molecular", Department of Chemistry, Faculty of Science and Technology, University of Coimbra, P-3004-535 Coimbra, Portugal.
authors.forename: S M
authors.initials: SM
authors.lastname: Fiuza
authors.affiliation: I&D Unit "Química-Física Molecular", Department of Chemistry, Faculty of Science and Technology, University of Coimbra, P-3004-535 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
authors.forename: M P M
authors.initials: MPM
authors.lastname: Marques
authors.affiliation: I&D Unit "Química-Física Molecular", Department of Chemistry, Faculty of Science and Technology, University of Coimbra, P-3004-535 Coimbra, Portugal.
authors.forename: L A E
authors.initials: LAE
authors.lastname: Batista de Carvalho
authors.affiliation: I&D Unit "Química-Física Molecular", Department of Chemistry, Faculty of Science and Technology, University of Coimbra, P-3004-535 Coimbra, Portugal. Electronic address: amado.am@gmail.com.
authors.forename: A M
authors.initials: AM
authors.lastname: Amado
keywords: Conformational preferences; Dielectric constant effect; Norspermidine; Quantum chemical calculations; Vibrational spectroscopy