title: The structure of acrolein in a liquid crystal phase.
abstract: The (1)H NMR spectrum of a sample of acrolein dissolved in the nematic liquid crystal phase I52 has been analysed to yield 18 dipolar couplings between all the magnetic nuclei in the molecule; moreover, the (13)C and (13)C{(1)H} NMR spectra of a sample of acrolein in CDCl(3) were recorded and analysed to determine the indirect J(ij) couplings. The data were used to obtain the relative positions of the carbon and hydrogen atoms, assuming that these are independent of the conformations generated by rotation around the C--C bond through an angle phi, and to obtain a probability distribution P(phi). It has been found that in the liquid phase, the distribution is a maximum at the trans form whereas the abundance of the cis form is significantly smaller compared with that found by microwave spectroscopy or high level quantum mechanical calculations. Such calculations produced also a suitable force field needed to develop suitable strategies for vibrational correction procedure in the case of flexible molecules.
authors.affiliation: Università della Calabria, Dipartimento di Chimica, Arcavacata di Rende (Cs), Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Celebre
authors.forename: Maria
authors.initials: M
authors.lastname: Concistrè
authors.forename: Giuseppina
authors.initials: G
authors.lastname: De Luca
authors.forename: Marcello
authors.initials: M
authors.lastname: Longeri
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pileio
authors.forename: James William
authors.initials: JW
authors.lastname: Emsley
mesh_terms: D000171:Acrolein / Q000737:chemistry*; D003460:Crystallization; D003510:Cyclohexanes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D008872:Microwaves; D008956:Models, Chemical; D015394:Molecular Structure; D012015:Reference Standards; D013237:Stereoisomerism
chemical_list: D003510:Cyclohexanes; D000171:Acrolein