Kerr-effect Studies

Dipole-moment and Kerr-effect Studies.—Information on preferred conformations is provided by these techniques, although only a relatively limited precision is possible in estimates of molecular geometry. 

Aromatic disulphides and diselenides adopt a conformation in which the torsion angle between the C—S—S— and —S—S—C— planes lies between 70 and 90°. Related studies of aliphatic disulphides have also been undertaken. Comparisons of S, Se, and O analogues represented by ArXMe, (At = Ph or mem-substituted phenyl) and aryl diarylmethyl sulphides have been made, in terms of their conformational behaviour. Studies of diaryl ditellurides ArTeTeAr and phenyl tellurobenzoates PhCOTeR provide dipole-moment data consistent with a non-planar C conformation and planar Z conformation, 

Guimon, M. F. Guimon, and G. Pfister-Guillouzo, Tetrahedron Letters, 1975, 1413. 

Bernard , G. Distefano, A. Mangini, S. Pignataro, and G. Spunta, J. Electron Spectroscopy Related Phenomena, 1975,7, 457. 

Jehlicka, J. L. Piette, and O. Exner, Coll. Czech. Chem. Comm., 1974,39,1577. 

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Combined dipole moment and Kerr effect studies are regularly used by Russian workers for the conformational analysis of phosphorus heterocyc1es.135 230 In a study of the interaction of phenol with phosphoryl groups the Kerr effect was used to evaluate not only the extent of hydrogen bonding but also the influence of changes in polarity and polarisation upon stability constants.231 In a similar study the orientation of the aryl groups of 1,3,5-triazaphosphorines (82) were shown to be less coplanar than biphenyl in the gas phase. 2 3 2... 

Loughnane BJ, Fourkas JT. Geometric effects in the dynamics of a nonwetting liquid in microconfinement an optical Kerr effect study of methyl iodide in nanoporous glasses. J Phys Chem B 1998 102 10288-10294. 

Quite vis EF, Neelakandan M. Femtosecond optical Kerr effect studies of liquid methyl iodide. J Phys Chem 1996 100 10005-10014. 

On the assumption of total symmetry of the tensor of third-order nonlinear polarizability c(— co coi, cog, cog), its non-zero and independent elements are the same as those of Table 12. Direct theoretical calculations of c = c(0 0,0,0) have been performed for the atoms of inert gases and some simple molecules. Values of the tensor elements = c(— cu cu, 0,0) have been determined for numerous molecules from static Kerr effect studies and values of c = c(— cd ot>,coi — col) from measurements of optical birefringence induced by laser li t. Measurements of second-harmonic generation by gases in the presence of a static electric field yield the tensor elements c " = c( — 2co co, to, 0), which can also be obtained from second-harmonic scattering in centro-symmetric liquids. The elements of the tensor c = c(— 3co co, co, co)... 

Only recently a dynamic Kerr effect study on QPVP and NaPSS [169] investigated the effect of intermolecular interaction on the field-free decay of the birefringence at very low polyion concentration without added salt, with the remarkable result that a maximum of the decay time is observed in each of the two relaxation processes at approximately the same concentrations where the viscosity displays a maximum and the scattering techniques show a structure peak (Fig. 10). Whereas the longer relaxation process is identified as the overall rotation of the polyion, the fast relaxation has become a matter of extensive speculation. 

As already mentioned in Sect. 3.3.3, Nishida and Kaji [75, 269] calculated the influence of intermolecixlar interaction on the intrinsic viscosity of spheres. Assuming the interaction effect on the viscosity of spheres and flexible coils to be comparable they corrected the experimental viscosity data which also exhibit a peak as a function of concentration by the calculated contribution from the interaction. The remaining part of the intrinsic viscosity shows a continuous increase as a function of ionic strength which levels off to a constant value at low ionic strength. Interpretations of these intrinsic viscosities are in qualitative agreement with dynamic Kerr effect studies [270, 271] and Tricot s data analysis. 

Bartolini, P., Eramo, R., Taschin, A. and Torre, R. (2007). A superheterodyne-detected optical-Kerr-effect study of supercooled water dynamics. In preparation. 

Tsuzuki, S. Tokuda, H. Hayamizu, K Watanabe, M. (2005). Magnitude and directionality of interaction in ion pairs of ionic liquids relationship with ionic conductivity. Journal of Physical Chemistry B, 109,16474-16481 Turton, D. A. Hunger, J. Stoppa, A. Hefter, G. Thoman, A. Walther, M. Buchner, R Wynne, K. (2009). Dynamics of imidazolium ionic liquids from a combined dielectric relaxation and optical Kerr effects study evidence for mesoscopac aggregation. Journal of the American Chemical Society, 131,11140-11146 Urahata, S. M. Ribeiro, M. C. C. (2005). Single particle dynamics in ionic liquids of 1-alkyl-3-methylimidazolium cations. Journal of Chemical Physics, 122,024511/1-9 Wang, Y. Voth, G. A. (2006). Tail aggregation and domain diffusion in ionic liquids. Journal of Physical Chemistry B, 110,18601-18608 Wasserscheid, P. Welton, T., Eds. (2008). Ionic Liquids in Synthesis, 2nd Ed., WILEY-VCH, ISBN 978-3-527-31239-9, Weinheim... 

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