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Order and Conformation of Biphenyl in Cyanobiphenyl Liquid Crystals: A Combined Atomistic Molecular Dynamics and 1 H NMR Study
Author(s) -
Pizzirusso Antonio,
Di Pietro Maria Enrica,
De Luca Giuseppina,
Celebre Giorgio,
Longeri Marcello,
Muccioli Luca,
Zani Claudio
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201400082
Subject(s) - liquid crystal , biphenyl , magnetic dipole–dipole interaction , residual dipolar coupling , molecular dynamics , nuclear magnetic resonance spectroscopy , chemical physics , chemistry , dipole , crystallography , phase (matter) , spectroscopy , materials science , nuclear magnetic resonance , computational chemistry , stereochemistry , organic chemistry , physics , optoelectronics , quantum mechanics
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.