title: Electrical and mechanical anharmonicities from NIR-VCD spectra of compounds exhibiting axial and planar chirality: the cases of (S)-2,3-pentadiene and methyl-d(3) (R)- and (S)-[2.2]paracyclophane-4-carboxylate.
abstract: The IR and Near infrared (NIR) vibrational circular dichroism (VCD) spectra of molecules endowed with noncentral chirality have been investigated. Data for fundamental, first, and second overtone regions of (S)-2,3-pentadiene, exhibiting axial chirality, and methyl-d(3) (R)- and (S)-[2.2]paracyclophane-4-carboxylate, exhibiting planar chirality have been measured and analyzed. The analysis of NIR and IR VCD spectra was based on the local-mode model and the use of density functional theory (DFT), providing mechanical and electrical anharmonic terms for all CH-bonds. The comparison of experimental and calculated spectra is satisfactory and allows one to monitor fine details in the asymmetric charge distribution in the molecules: these details consist in the harmonic frequencies, in the principal anharmonicity constants, in both the atomic polar and axial tensors and in their first and second derivatives with respect to the CH-stretching coordinates.
authors: Dipartimento di Scienze Biomediche e Biotecnologie, Università di Brescia, Viale Europa 11, 25123 Brescia, Italy. abbate@med.unibs.it
authors: Sergio
authors: S
authors: Abbate
authors: Giovanna
authors: G
authors: Longhi
authors: Fabrizio
authors: F
authors: Gangemi
authors: Roberto
authors: R
authors: Gangemi
authors: Stefano
authors: S
authors: Superchi
authors: Anna Maria
authors: AM
authors: Caporusso
authors: Renzo
authors: R
authors: Ruzziconi
mesh_terms: D000465:Algorithms; D000466:Alkadienes / Q000737:chemistry*; D001952:Bridged-Ring Compounds / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D002942:Circular Dichroism / Q000379:methods*; D015394:Molecular Structure; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared / Q000379:methods*
chemical_list: C570214:(S)-(2,2)paracyclophane-4-carboxylate; D000466:Alkadienes; D001952:Bridged-Ring Compounds; D002264:Carboxylic Acids