IR spectroscopic study of molecular aggregation in condensate films of polar liquid crystals

Polarized ATR-IR Studies of Surface-Field-Induced Anchoring of Alkyl Cyanobiphenyls

“…Finally, we note that there is a frequency shift associated with homeotropic anchoring but not with planar anchoring. Recent transmission IR experiments and theoretical calculations based on the GAMESS program suite have shown that this shift is associated with the formation of dimers. − This correlates well with the observation of complete orientational wetting by homeotropic nematic molecules at the substrate−isotropic interface, when the substrate is very low energy. Namely, such a class of complete wetting would have to be driven by nCB−nCB interactions and/or structural entropy.…”

Modeling structure and spectra of silver complexes in condensate films of polar liquid crystals

“…In the vicinity of R = 4.7 Å a sharp change in shape of the energy curve (Figure 3) indicates a drastic modification in the electron density distribution: an electron from the silver atom jumps to the ligands, and the chargetransfer (PhCN) 2 -Ag + configuration dominates at R < 4.7 Å. This observation is confirmed by direct calculations of the natural electronic charges 13 on the fragments of the complex: Ag, PhCN (1) and PhCN (2).…”

“…1 The reactions of metals with the molecules composing liquid crystals, in particular, cyanobiphenyl derivatives, are carried out under low-temperature conditions by condensing the molecular beams into thin films, and IR and UV spectral techniques are used to characterize the reaction products. 2,3 However, little is known about the structure of these intriguing substances and the experimental spectral patterns deserve theoretically motivated interpretations.…”

“…The system possesses planar symmetry with the silver atom placed at equal distances from the ligands, namely, from the centre of the CN fragment of ligand (1) and from the centre of the ring of ligand (2). In calculations, almost all the geometry parameters were fixed at the values of the free PhCN molecule, and the distance R between the planar ligands (1) and (2) was varied.…”

2-[3-Dicyanomethylene-2-(3-methoxybenzylidene)indan-1-ylidene]malononitrile

“…There are, however, two C-HÁ Á ÁN contacts which are slightly shorter than the corresponding sum of van der Waals radii (Table 1). In addition, there are short CNÁ Á ÁCN contacts, which probably compete with hydrogen bonds (Hori et al,2000;Shabatina et al, 1997;Kuribayashi et al, 1999): N52Á Á ÁC52 i = 3.064 (7) Å and N52Á Á ÁC51 ii = 3.236 (7) Å [symmetry codes: (i) 1 2 À x; Ày; 1 2 þ z; (ii) x; y; 1 þ z]. Interestingly, (I) crystallizes in a non-centrosymmetric space group despite the absence of any stereogenic centres.…”