New chiral discotic triphenylene derivatives exhibiting a cholesteric blue phase and a ferroelectrically switchable columnar mesophase

Abstract

We have synthesized a number of new achiral and chiral triphenylene derivatives bearing laterally substituted phenylene units in the side chains. Their polymorphism includes the ®rst reported discotic blue phase of a pure compound and a ferroelectrically switchable columnar mesophase.

Chiral Discotic Molecules: Expression and Amplification of Chirality

“…55 More recently, chiral triphenylene derivatives (e.g., 50) were also reported to exhibit ferroelectrically switchable columnar mesophases or a cholesteric blue phase. 56 adding dodecane could reduce the viscosity of the system, thereby decreasing the response time of the system. 57 With these lyotropic mesophases switching at temperatures as low as room temperature was even possible.…”

“…As a consequence the observed mesophase was not ferroelectric. Malthete and Collet further developed the system and synthesized a chiral cyclotribenzylene (56), in order to study the racemization rate of the cones in the columnar mesophase (i.e., the rate with which the cone inverts). 67 The rate of racemization was found to be highly dependent on the temperature.…”

Interplay between polarity and chirality in the electric-field-responsive columnar phase of a dipeptide derivative

“…Similar EO rotation was observed in some columnar phases. [9][10][11] The behavior appears similar to the electroclinic (EC) effect observed in the smectic A phase composed of chiral molecules (SmA*). 12,13 The optical axis rotation is proportional to the electric field strength, E, in the EC effect as a result of a linear coupling of the applied electric field and an induced polarization.…”

“…The rotation axis of Col ob is along the column axis, not perpendicular to the column axis as in the other reported columnar phases. [9][10][11] In addition, there are notable differences in the rotation angle and the response time: the rotation angle in the Col ob phase is small (less than 1 1), whereas the saturation values were greater than 10 1 in other phases. [9][10][11] Moreover, the relaxation frequency was approximately 12 Hz (Figure 3b) in the Col ob phase, which is much lower than that in the SmA* phase.…”

A columnar mesophase with high lateral order from a triphenylene-hexa(3,5-dialkoxy)benzoate

“…Broadening of the mesophase range is mostly achieved by frustrating the crystallisation process, thus specifically lowering the melting temperature. The extreme case of such broadening is demonstrated for triphenylene benzoate esters with a chlorine or nitro group in the meta position [19].…”