Studies of Calamitic Liquid Crystalline Compounds Involving Ester-Azo Central Linkages with a Biphenyl Moiety

Autor:	N. B. Patel, J. B. Kanojiya, D. B. Solanki, B. T. Thaker, B. S. Patel, N. J. Chothani, Y. T. Dhimmar
Rok vydání:	2011
Předmět:	Biphenyl Phase transition Hydrogen bond Mesogen chemistry.chemical_element General Chemistry Condensed Matter Physics Photochemistry chemistry.chemical_compound Homologous series Crystallography chemistry Phase (matter) Moiety General Materials Science Carbon
Zdroj:	Molecular Crystals and Liquid Crystals. 548:172-191
ISSN:	1563-5287 1542-1406
DOI:	10.1080/15421406.2011.591677
Popis:	Two mesogenic homologous series involving ester-azo central linkages with a biphenyl moiety have been synthesized, such as 4′-[(4-n-alkoxyphenyl)diazenyl]biphenyl-4-ol (series I) and 4′-[(4-n-alkoxyphenyl) diazenyl]-4-butoxy phenyl biphenyl-4-carboxylate (series II). Azobiphenyl of series I having a free hydroxyl group with strong hydrogen bonding exhibits a high-temperature enantiotropic smectic phase. Whereas in series II, compounds containing C1–C8 carbon atoms exhibit only a monotropic smectic phase and compounds with C10, C12, C14, and C16 atoms show an enantiotropic smectic phase. These compounds were characterized by elemental analysis, FT-IR, 1H-NMR, and mass spectral studies. The phase transition and mesogenicity of these substances were studied by polarizing optical microscopic and differential scanning calorimetric techniques. Their thermal stabilities and other characteristics are discussed.
Databáze:	OpenAIRE
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