| Abstract
| - The present study of the ordering of apolar molecules dissolved in uniaxial mesophases has been carried outby a model where the interactions between the solute and the local medium are described on a molecularscale. On the contrary, the mutual interactions between the solvent molecules are not explicitly taken intoaccount, but a mean description of the macroscopic anisotropy of the bulk of the solvent is provided. This isdone by defining a “virtual” mesophase director whose instantaneous orientation in the solute molecularframe is randomly given step-by-step during the numerical calculation of the solute order parameters. Thismodel has been applied to apolar molecules biphenylene, 1,4-dicyanobenzene, 1,4-dinitrobenzene, andp-benzoquinone. The predicted order parameters have been compared with the 1H NMR experimental dataobtained for the same compounds dissolved in nematic solvents EBBA and ZLI1132 and in the 55 wt %ZLI1132 + EBBA magic mixture, where long-range effects are believed to be very small. A nearly perfectmatching of the simulated solute-ordering matrices with the data in the magic mixture has been found, thusstrengthening the common assumption that long-range effects can be neglected in that mixture. The modelhas also been tested on so-called magic solutes cyclohexane, 1,4-trans-dimethylcyclocyclohexane, and trans-decalin (whose electronic structure should preclude significant anisotropic long-range interactions) dissolvedin ZLI2452. Once more, we obtained excellent results in reproducing the experimental order parameters (Terzis,A. F.; Poon, C.-D.; Samulski, E. T.; Luz, Z.; Poupko, R.; Zimmermann, H.; Muller, K.; Toriumi, H.; Photinos,D. J. J. Am. Chem. Soc.1996, 118, 2226) over a very large range of temperatures, and this is a furtherevidence of the validity of the approach.
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