Physico-Chemical Properties of New Liquid Crystals Incorporating a Lactone Ring

ABSTRACT

Synthesis and physico-chemical properties of 4-alkoxyphenyl and 4-alkoxybiphenyl-4′-yl 2H-pyran-2-one-5-carboxylates, 2H-chromen-2-one-6-yl 4-alkoxybenzoates and 4-alkoxybiphenyl-4′-carboxylates, and 2H-chromen-2-one-7-yl 4-alkoxybenzoates and 4-alkoxybiphenyl-4′-carboxylates are described. Terminal 2H-pyran-2-one and chromen-2-one cores are effective in enhancing liquid crystalline properties. The layer structure was examined by a small angle X-ray measurement, and the results are discussed in terms of the molecular structure. The polar effect of the terminal lactone group is recognized in the thermal properties and the layer structure of smectic A (SmA) phase.

Keywords:

• 2H-chromen-2-one
• 2H-pyran-2-one
• layer structure
• liquid crystal
• smectic A phase

Acknowledgments

This work was partially supported by The Sumitomo Foundation.

Notes

C, SmA, N, and I indicate crystal, smectic A, nematic, and isotropic phases, respectively. Parentheses represent a monotropic transition temperature.

*1 A schlierene texture was observed before recrystallization.

*2 Transition temperatures were determined from binary phase diagrams, for example, in Figure 6a.

*1 A schlierene texture was observed before recrystallization.