All-organic liquid crystalline radicals with a spin unit in the outer position of a bent-core system

All-organic paramagnetic liquid crystals offer the advantage of a long-range order of liquid crystalline phases and the magnetic properties of the individual molecules. In such systems, the magnetic properties can be modified by phase transition or the application of external fields. In our work paramagnetic all-organic bent-core liquid crystals having the radical-bearing unit (TEMPO) in the terminal position of an elongating side arm are studied.

The mesomorphic properties of the materials are ensured by the optimized molecular structure. The paramagnetic nature of the mesogenic materials is investigated by electron paramagnetic resonance, the magnetic properties of the bulk materials are studied by SQUID magnetometry. It is shown that the materials preserve their magnetic properties within the whole temperature range of liquid crystalline behaviour. Moreover, a strong correlation between spin orientation and molecular alignment within different mesophases has been observed [ K. Bajzıkova er al, J. Mater. Chem. C 4, 11540 (2016). ].

Figure: Texture in the smectic C phase for the paramagnetic liquid crystalline compound.