No abstract

New series of dimeric molecules with flexible spacers are described in which the mesogenic salicylaldimine group is linked to the alkylene spacer via an imino group. To study the structure−property relations, the lengths of the alkylene spacers (m = 5−8) as well as those of the terminal alkoxy chains (n = 4−14) have been varied. The compounds with even-numbered spacers behave as classic rodlike mesogens displaying nematic and/or smectic C phases, while those with odd-numbered spacers show nematic, columnar nematic, and columnar rectangular phases, behaving as bent-core mesogens. The effect on the liquid-crystalline behavior of the effective geometric change arising from the spacer parity and the imino linkage is discussed.

No abstract

Combined studies support the hierarchical model for the NTB phase that involves formation of embryonic self-assembly of the propeller-shaped dimeric molecules with syn-parallel orientation in the isotropic melt.

Table S1. X-ray data from the 2D patterns: (2obs … experimental scattering angle; dobs … experimental d value; n … order of reflection and d … layer spacing: for the SmCC phase). a) Position of the maxima of the diffuse scattering and the layer reflections in the small angle region (because of the shape of the diffuse scattering curves the values are of limited accuracy, especially those for the very weak innermost maxima or shoulders): Compound T/°C Phase 2obs/° dobs/nm n d / nm * Data from wide angle patterns (sampledetector distance = 9.3 cm) # The discrepancies between these values and those cited in [10] result from the very limited accuracy of the determination of the maxima for the inner diffuse scattering in the WAXD patterns used in [10].

The interplay between the molecular geometry and π–π interactions affects the thermal stability of a twist-bend nematic.

No abstract

Three new series of symmetric dimers containing a naphthoyloxybenzyl (NB), benzoyloxynaphthyl (BN), and naphthoyloxysalicyl (NS) mesogenic core linked to an alkylene spacer via an imino group were synthesized. The effects of the variant spacer parity as well as the variant core structure on the mesomorphic properties have been studied. The dimers having NB and BN mesogenic units display intercalated smectic structures regardless of the spacer parity. In contrast, bilayer smectic and Colrec structures are observed for the NS core compounds with even and odd spacers, respectively. The influence of geometric and electronic factors on the mesomorphic behavior, in particular on the molecular packing within the smectic phase, is discussed based on conformational and dipolar considerations following DFT calculations using model molecules. The difference in self-organization of symmetric naphthyl-based dimers appears to be governed by the competition between geometric factors and dipole-dipole interactions between identical mesogenic units.