ABSTRACT
C(60).C(8)H(8) and C(70).C(8)H(8) are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C(60)C(8)H(8)) and poly(C(70)C(8)H(8)) resulting from a solid-state reaction occurring on heating. On the basis of the spectra, we propose a connection pattern for the fullerene in poly(C(60)C(8)H(8)), where the symmetry of the C(60) molecule is D(2h). On illuminating the C(60).C(8)H(8) cocrystal with green or blue light, a photochemical reaction was observed leading to a product similar to that of the thermal polymerization.
ABSTRACT
A carbon-13 NMR study in a series of bent-core (banana-shaped) molecules is reported. In 1, 3- phenylene bis[4'-alkenyloxy biphenyl]-4-carboxylate derivatives the position of the chlorine substituent(s) connected to the central phenyl ring and/or the terminal chain length of the compounds were varied. By analyzing the observed chemical shift anisotropies, the order parameters S and bending angles in their nematic phase are compared. The biphenyl moiety on each arm of the molecular core is found to form a nonzero twist angle.