Mesomorphic property of 2,5-dibenzoyloxy-, 5-benzoylamino-2-benzoyloxy-, and 2,5-dibenzoylamino-tropones with mono-, di-, and tri-alkoxyl groups on the benzoyl groups and their benzenoid derivatives

Abstract

Mesomorphic properties of three-ring systems such as 2,5-dibenzoyloxytropones, 5-benzoylamino-2-benzoyloxytropones and 2,5-dibenzoylaminotropones with 4-alkoxy, 3,4-dialkoxy, and 3,4,5-trialkoxy groups on the benzoyl groups were investigated together with those of the corresponding benzenoids. Derivatives with two monoalkoxybenzoyl groups showed nematic and smectic A and C phases. Troponoid tetracatenars with two dialkoxybenzoyl groups had hexagonal columnar phases except for troponoids with two ester-connecting groups, whereas the corresponding benzenoids with two dialkoxybenzoyl groups were non-mesomorphic. All troponoid hexacatenars with two trialkoxybenzoyl groups formed hexagonal columnar phases. With the exception of benzenoid hexacatenars with two ester-connecting groups, the benzenoid hexacatenars showed hexagonal and tetragonal columnar phases. These mesomorphic properties were discussed from the standpoint of the difference of the core structure and the connecting group, where the amide-connecting group played a role to induce and enhance mesomorphic properties through hydrogen bonding.

Novel synthesis of benzotriazolyl alkyl esters: an unprecedented CH2 insertion

“…Aminotropones were reported to couple with similar acylating reagents such as acid chlorides under conventional reaction conditions. 29,30 When we reacted aminotropone 1a with acyl benzotriazole 2a in acetonitrile (ACN) in presence of Hunig's base ( Scheme 1 ) according to standard protocol of coupling using N -acyl benzotriazole as an acylating reagent, 16,22 we observed no progress after one hour of stirring at room temperature, and the starting materials were largely insoluble. Therefore, we added few drops of dichloromethane (DCM) as a co-solvent to enhance the solubility of the starting materials.…”

Peripherally Modified Tetraphenylethene: Emerging as a Room-Temperature Luminescent Disc-Like Nematic Liquid Crystal

“…Then, four peripheral substitutions of 3,4,5-tri­(hexyloxy)­benzyl were linked to the TPE core via benzyl ether bonds, which gifted the material with liquid crystallinity on one hand and contributed to diminishing the face-to-face-styled intermolecular correlations on the other hand. In addition, compared with the conventional ester- or amide-fashioned linking groups, , the selection of the less polar benzyl ether linkage increased the flexibility and further lowered the phase-transition temperature. Here, we will demonstrate that compound 1 shows a broad mesophase range with the transition to the nematic phase occurring at a temperature close to RT, that this material retained its highly emissive property even in its isotropic state, and that 1 behaved as a non-volatile organic solvent which can be used to dissolve a red luminogen and the stable mixture emitted polarized white light under the UV light at 365 nm.…”

Substituted Aroylhydrazone Based Polycatenars: Tuning of Liquid Crystalline Self‐Assembly

“…Apart from conventional rod‐like and disc‐like mesogens, the nonconventional systems like bent core, polyhydroxyamphiphiles, oligomers, star‐shaped molecules, dendrimers and polycatenar mesogens based on variety of cores have been intensively studied . The polycatenars, or phasmid‐like LCs, are nonconventional LCs with a dumbbell shape, comprising a central long aromatic rod connected to two terminal semi‐discs with multiple flexible chains . These molecules self‐assemble into different LC phases due to the nanosegregation of aromatic units and flexible chains and very sensitive to small structural changes which greatly affect their macroscopic self‐assembly and hence their mesogenic properties .…”