Mesomorphic behaviour of N,N-dialkanoyl-3,4,5,6-tetramethylbenzene-1,2-diamines and related compounds
Titel:
Mesomorphic behaviour of N,N-dialkanoyl-3,4,5,6-tetramethylbenzene-1,2-diamines and related compounds
Auteur:
Verschenen in:
Liquid crystals
Paginering:
Jaargang 27 (2000) nr. 11 pagina's 1399-1403
Jaar:
2000-01-01
Inhoud:
DSC, X-ray, broad-line proton NMR, and microscopy studies on several series of N,N' -dialkanoylbenzene-1,2-diamines are presented. The melting point and associated enthalpy are not much affected by methylation of the aromatic nucleus. While the dimethyl compounds carrying heptanoyl-to-hexadecanoyl groups generate metastable mesophases below 111oC, the 3,4,5,6- tetramethyl compounds carrying propionyl-to-hexadecanoyl groups produce stable hexagonal columnar mesophases appearing mostly above 200oC. N,N'-dialkylbenzene-1,2-carboxamides are transformed into birefringent viscous fluids exhibiting a focal-conic texture at a temperature between 76 and 99oC when the alkyl groups are decyl, undecyl, dodecyl, and tetradecyl.
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