title: Rotational isomerism of some chloroacetamides: theoretical and experimental studies through calculations, infrared and NMR.
abstract: The geometries involved in the conformational equilibria of 2,2-dichloro-N-cyclohexyl-N-methyl-acetamide (DCCMA) and 2-chloro-N,N-dicyclohexylacetamide (CDCA) were investigated. Theoretical calculations at the B3LYP/cc-pVDZ level of theory showed that gauche forms (ClCCO) are the most stable and the predominant conformers in isolated phase. Both compounds had the conformational behavior in solvents of different polarities estimated from theoretical calculations with the PCM (Polarizable Continuum Model), at the same level of theory, using infrared data from deconvolution of the carbonyl absorption bands and (13)C NMR spectra. Their IR spectra showed two carbonyl absorptions and that the conformer with the highest dipole moment had its population increased when the most polar solvents were used, in accordance with the theoretical calculation in solution. (1)JCH coupling constants were obtained from their NMR spectra, and revealed that there was population variation of conformers with solvent exchange. Experimental data (NMR and IR) as well as calculations including the solvent effects followed the same trend.
authors.affiliation: Departamento de Química, Universidade Estadual de Ponta Grossa/UEPG, Av. General Carlos Cavalcanti 4748, 84030-900 Ponta Grossa, PR, Brazil.
authors.forename: Marcela F
authors.initials: MF
authors.lastname: Santos
authors.affiliation: Departamento de Química, Universidade Estadual de Ponta Grossa/UEPG, Av. General Carlos Cavalcanti 4748, 84030-900 Ponta Grossa, PR, Brazil.
authors.forename: Carolyne B
authors.initials: CB
authors.lastname: Braga
authors.affiliation: Departamento de Química, Universidade Estadual de Maringá/UEM, Av. Colombo 5790, 87020-900 Maringá, PR, Brazil.
authors.forename: Thiago C
authors.initials: TC
authors.lastname: Rozada
authors.affiliation: Departamento de Química, Universidade Estadual de Maringá/UEM, Av. Colombo 5790, 87020-900 Maringá, PR, Brazil.
authors.forename: Ernani A
authors.initials: EA
authors.lastname: Basso
authors.affiliation: Departamento de Química, Universidade Estadual de Ponta Grossa/UEPG, Av. General Carlos Cavalcanti 4748, 84030-900 Ponta Grossa, PR, Brazil. Electronic address: bcfiorin@uepg.br.
authors.forename: Barbara C
authors.initials: BC
authors.lastname: Fiorin
mesh_terms: D000081:Acetamides / Q000737:chemistry*; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D013055:Spectrophotometry, Infrared
chemical_list: D000081:Acetamides; C013874:chloroacetamide
keywords: Chloroacetamides; Conformational analysis; Infrared spectroscopy; NMR spectroscopy; Theoretical calculations