Columnar mesophases constructed by hierarchical self-organization of rod-like diacetylene molecules

Tunable Emissive Lanthanidomesogen Derived from a Room‐Temperature Liquid‐Crystalline Schiff‐Base Ligand

“…In the low‐angle region, sharp peaks observed corresponding to d spacings of 47.7, 28.2, and 23.8 Å in the ratio 1:0.59:0.5 suggest a columnar phase with 2D hexagonal ordering with a lattice dimension of 56.1 Å 24a. Pertinent here is to mention that in addition to planar disc‐like molecules, many other molecular shapes may also give rise to a columnar‐type of organization 24b–h. The lattice constant ( a =56.1 Å) is much larger than the monomeric molecular length of 28.04 Å for a fully extended molecule, as calculated from a DFT study.…”

“…The observed stacking distance within a column ( h =4.2 Å) is greater than that expected (3.5 Å) for π–π stacking with a “face‐to‐face” orientation of the aromatic cores. This is accounted for by invoking “edge‐to‐edge” stacking of the molecules in the column 24h. Therefore that the tapered rod‐like molecular motifs may also lead to the supramolecular columnar liquid‐crystalline assembly.…”

Augmenting Photoinduced Charge Transport in a Single‐Component Gel System: Controlled In Situ Gel–Crystal Transformation at Room Temperature

“…The gel prepared at a relatively higher concentration of TPAPAE (c = 1 wt %) at some places show ripening of smaller aggregates within the self‐assembled fibers (Figure d), whereas at other places show ordered rectangular shaped fine‐scale aggregates formed from the fibrous networks, see Figure e. The corresponding SAED image for the ordered aggregates in Figure f revealed an increase in crystallinity with distinct spots in the diffraction pattern. With respect to c = 0.5 wt %, the PXRD peaks in the small angle scattering region for c = 1 wt % xerogel depicts an increase in 2 θ values, owing to relative shortening of d values, as shown in Figure c. The most intense peaks in the small angle scattering region are 15.29 Å ( d 200 , 2 θ =5.77°) and 10.66 Å ( d 020 , 2 θ =7.59°), which accounts for a ratio of 1:1/√2, suggesting a rectangular‐columnar ( Col r ) self‐assembly pattern of P 2 1 / a symmetry, with lattice constants a= 29.96 Å and b= 11.0 Å. The molecular packing giving rise to maximal CSO of thick fibers, which leads to ripening of ordered Col r crystalline aggregates is shown in Scheme C.…”

“…This change in molecular packing pattern is shown in Scheme B. The most intense peaks in the small‐angle scattering region are 15.93 Å ( d 200 , 2 θ =5.54°), 14.54 Å ( d 110 , 2 θ =6.07°), 10.47 Å ( d 020 , 2 θ =8.43°) and 7.64 Å ( d 400 , 2 θ =11.56°), corresponding to a rectangular‐columnar ( Col r ) arrangement of P 2 1 / a symmetry, with lattice constants a= 31.86 Å and b= 16.34 Å, from the d 200 and d 110 spacings, respectively. A sharp diffraction peak at 2 θ =27.20° corresponds to d= 3.29 Å, accounting for the π‐stacking interactions of the peripheral o ‐benzoxy rings of PAE dendrons.…”

Flying-seed-like liquid crystals 3: new guideline for the induction of mesomorphism by using bulky groups instead of long alkyl chains

“…It is well known and established that long alkyl-chain-substituted benzoic acid derivatives form dimers by hydrogen bonding and show mesomorphism [16][17][18] . The present phenoxybenzoic acid derivatives nPh-PhOBA (3a~d) may also form dimers as illustrated in Scheme 1.…”