NEW MESOGENIC BENZENE-DERIVATIVES - N,N',N''-TRIALKANOYL-2-ALKANOYLOXY-1,3,5-BENZENETRIAMINES, N,N',N''-TRIALKANOYL-2,4-BIS(ALKANOYLOXY)-1,3,5-BENZENETRIAMINES, AND N,N'-DIALKANOYL-4,5,6-TRIS(ALKANOYLOXY)-1,3-BENZENEDIAMINES

Three new series of mesogenic benzene derivatives have been synthesized. N,N',N''-Trialkanoyl-2-alkanoyloxy-1,3,5-benzenetriamine exhibits a hexagonal disordered columnar phase when the alkanoyl group is valeryl or longer, the temperature range of stable existence of the mesophase being as wide as 78 to 118-degrees-C. The addition of a second OCOC(n)H2n+1 group to this compound does not affect appreciably the clearing point but depresses the melting point by 28 to 78-degrees-C. The enthalpies at the clearing point are anomalously large in this series; that is, 40 to 58 kJ mol-1. Nevertheless, the second moments of the broad-line NMR spectra of the heptanoyl and hexadecanoyl derivatives are 0.1 G2 or less in the mesophases in accordance with the hexagonal disordered columnar phase assigned on the basis of the X-ray diffraction patterns. The replacement of an NHCOC(n)H2n+1 group in the second compound by an OCOC(n)H2n+1 group resulted in lowering the clearing point by 21 to 45-degrees-C and raising the melting point by 12 to 37-degrees-C and the decrease of the enthalpy at the former transition by a factor of two or more.