2,5-Diaryl-1,3,2-dioxaborinanes: A New Series of Liquid Crystals

Abstract

2,5-Diaryl-1,3,2-dioxaborinane derivatives having various terminal groups were synthesized and found to form mesomorphic phases in a wide temperature range. They provide a new series of liquid-crystalline compounds containing a boron atom in the principal structure.

Mesogenic, optical, and dielectric properties of 5-substituted 2-[12-(4-pentyloxyphenyl)-p-carboran-1-yl] [1,3]dioxanes

“…14 Arylation of diethyl malonate with 4-substituted aryl iodides, 11[n] and 12[n], and preparation of 9[n] and 10[n] was accomplished using CuI according to a general method. 15 All intermediates 5[n]-10[n] used in this work have been reported in the literature [16][17][18][19][20] but many lack analysis. For completeness of the work, 1 H and 13 C NMR data for all intermediates is reported in the ESI.…”

Boronic esters: a simple route to discotic liquid crystals that are electron deficient

“…Boron containing calamitic liquid crystals are known, with Kaszynski et al incorporating p-carborane cages 21 and Takahashi et al incorporating aliphatic boronates. 22 Catechol-based boronic esters were studied as liquid crystal candidates but did not give any mesophases. 23 Boronic esters of hexahydroxytriphenylene have received attention as components in covalent organic frameworks (COFs) 24 due to their strength and reversible formation in the solid state.…”

Crystal engineering gone awry and the emergence of the boronic acid–carboxylate synthon

“…However, while the formation of B-N adducts has been shown to take place with boroxine, there are no known structures of an intermolecular B-N adduct forming with the boronic acid moiety intact. 7 We now present the three crystal structures that resulted from the three supramolecular synthetic challenges described above; 4-diaminomethylpyridine and 4-carboxyphenylboronic acid, 1; 4-acetylpyridineoxime and 4-carboxyphenylboronic acid, 2; and 2-methylimidazole and 4-carboxyphenylboronic acid, 3. Experimental Synthesis 4-Carboxyphenyl boronic acid was prepared using reported methods, 17 and all other chemicals were obtained from commercial sources. Solutions of the appropriate heterocycle and 4-carboxyphenyl boronic acid, both in an ethanol-water mix (1 : 1), were placed in a beaker and allowed to slowly evaporate at room temperature.…”