Indene and Pseudoazulene Discotic Liquid Crystals: A Synthetic and Structural Study

Abstract

Several new liquid-crystalline indene and pseudoazulene systems are reported. These molecules give rise to either columnar hexagonal mesophases and/or columnar plastic phases. The unique nature of these compounds stems from their non-classical discotic structure. Although the molecules have rigid aromatic cores, they lack terminal tails and instead the polarizable atoms (S, halogens) or polar groups (CN, CO) act as unusual soft parts. On the basis of many structurally related materials, we conclude that for this type of compound molecular stacking in the solid state is a prerequisite for the appearance of a columnar mesophase, although other intermolecular interactions within the layers are also important in establishing liquid-crystalline order. The behavior reported for these mesomorphic molecules opens up new possibilities in the search for related molecular interactions that might be useful for the construction of supramolecular architectures with particular properties.

Flying-seed-like liquid crystals. Part 4: a novel series of bulky substituents inducing mesomorphism instead of using long alkyl chains

“…When it was heated over the glass transition temperature at 87.4 o C, it relaxed to transform into crystalline phase K 1 ; on further heating, it transformed into another crystalline phase K 2 , which decomposed without weight 15 loss (1 st decomp.) just after melting at 299.4 o C and then decomposed with weight loss (2 nd decomp.)…”

“…X-ray data of 3b, 3c, 3e, 3f and 3g. Figure 5 illustrates dependence of the mesophase structure on the bulky substituent for the present flying-seed-like liquid crystals 15 based on (PhO) 8 PcCu. As can be seen from this figure, the bulkier the substituent becomes, the higher symmetry of mesophase becomes in order of (c, e)  f  g. Since the bulkiness of the substituent of c and e induced by flip-flop is the same, it may originate the same symmetry of P2 1 /a for 3c and 3e.…”

Flying-seed-like liquid crystals 5: Liquid crystals based on octakisphenylthiophthalocyanine and their optical properties

“…Accordingly, people have long believed that liquid crystals should have both a rigid central core and flexible peripheral alkyl chains. However, a very few liquid crystals being out of this common sense have been reported [4][5][6][7][8][9][10][11][12].…”

Site‐Selective Synthesis of Arylated Indenones by Suzuki–Miyaura Cross‐Coupling Reactions of 2,3,5‐Tribromoinden‐1‐one

“…Toluene cannot be used, due to competing benzylic bromination. Whereas 2,3-dibromoinden-1-one is known, [14] the synthesis of 2 has, to the best of our knowledge, not been previously reported.…”