title: Order and conformation of biphenyl in cyanobiphenyl liquid crystals: a combined atomistic molecular dynamics and 1H NMR study.
abstract: The alignment of biphenyl (2P) in the liquid-crystal phases of 4-n-pentyl-4'-cyanobiphenyl (5CB) and 4-n-octyl-4'-cyanobiphenyl (8CB) is investigated by using a combination of predictive atomistic molecular dynamics (MD) simulations and (1)H liquid-crystal nuclear magnetic resonance (LXNMR) residual dipolar coupling measurements. A detailed comparison and validation of the MD results with LXNMR is provided, showing a good agreement between the simulated and experimental dipolar couplings at the same reduced temperature. MD is then used to examine the location of 2P in the smectic phase, which is unavailable to LXNMR, and 2P is found to be rather uniformly distributed. The combination of MD and NMR spectroscopy provides detailed information about the order, interconnection between orientation and conformation, local positional order, and interactions with the liquid-crystalline solvent.
authors.affiliation: Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, 40136 Bologna (Italy).
authors.forename: Antonio
authors.initials: A
authors.lastname: Pizzirusso
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche Universit della Calabria, Via P. Bucci 87036 Arcavavata di Rebde (Italy).
authors.forename: Maria Enrica
authors.initials: ME
authors.lastname: Di Pietro
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche Universit della Calabria, Via P. Bucci 87036 Arcavavata di Rebde (Italy).
authors.forename: Giuseppina
authors.initials: G
authors.lastname: De Luca
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche Universit della Calabria, Via P. Bucci 87036 Arcavavata di Rebde (Italy). giorgio.celebre@unical.it
authors.forename: Giorgio
authors.initials: G
authors.lastname: Celebre
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche Universit della Calabria, Via P. Bucci 87036 Arcavavata di Rebde (Italy).
authors.forename: Marcello
authors.initials: M
authors.lastname: Longeri
authors.affiliation: Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, 40136 Bologna (Italy).
authors.forename: Luca
authors.initials: L
authors.lastname: Muccioli
authors.affiliation: Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, 40136 Bologna (Italy). claudio.zannoni@unibo.it
authors.forename: Claudio
authors.initials: C
authors.lastname: Zannoni
keywords: computer simulations; liquid crystals; nmr spectroscopy; residual dipolar coupling; solute