4′-(2-(2-Ethoxyethoxy)ethoxy)biphenyl-4-carboxylic acid—a polar smectogen for amphipathic liquid crystals

Symmetric bent-shaped liquid crystal dimers showing transitions between optically uniaxial and biaxial smectic phases

“…8BP5 was obtained by a condensation which consists of the in-situ treatment of the acid 2b with a cold mixture of SOCl 2 /pyridine followed by the addition of the diphenol (1). [30] This direct procedure as well as the one using N,N′-dicyclohexylcarbodiimide/4-dimethylaminopyridine and the esterification of the chloride derivative in pyridine at reflux temperature gave poor results for the other acids. Thus, the rest of the bent dimers and the zigzag dimer 8B were obtained by mild esterification, TEA/CH 2 Cl 2 at 4°C, via the acid chloride.…”

“…Notably, the SmA-SmC transitions are all easily detectable by DSC and show increased first-order character (Figure 1), although the transition from the orthogonal to the tilted smectic arrangements is of second-order nature for low molecular weight liquid crystals with the same mesogenic unit. [30] Finally, the longest dimers 12BP5 and 14BP5 showed that extending the terminal chain of 10BP5 with four and eight methylene groups substantially destabilised both nematic and SmA phases. In fact, 14BP5 is nematogenic only in a 3°C range and does not show a SmA phase; in contrast, the SmC phase was strengthened, appearing in a broad range of 60-70°C.…”

“…[30] The procedure for the synthesis of the bent dimers 7BP5, 2ʹ6BP5 and 10-14BP5 and the zigzag dimer 8 B is described in detail for 7BP5.…”

4′-[2-(2-Ethoxyethoxy)ethoxy]biphenyl-4-carboxylic acid: correlation between its crystalline and smectic phases

“…As part of a systematic study (Montani et al, 2009) with calamitic (i.e. rod-shaped) mesogens of three-block molecular architecture (biphenyl, aliphatic chains, oxyethylene chains), the LC behaviour of 4 0 -[2-(2-ethoxyethoxy)ethoxy]biphenyl-4-carboxylic acid, (I), has been studied.…”

Bent-shaped liquid crystal dimers. Influence of the direction of the oxybiphenylenecarboxyl groups on their mesomorphic behavior

“…9,10 (a1) (a2) (b1) (b2) Our aim was to study what role the direction of the whole mesogenic groups play on the mesomorphic behavior of dimers with biphenylene rigid units. 11 We synthesized a series of structurally related bent-shaped dimers in which both oxybiphenylenecarboxyl groups differ in their relative orientation along the long molecular axis of the dimer. The bent dimers have symmetric two-block molecular architectures with alternating non-polar aliphatic chains and rigid biphenylenes that are favorable for the generation of lamellar phases.…”