Scribbins, AC

The synthesis of five novel homologous series of 4'-n-alkoxybiphenyI-4-yl cycloalkanecarboxylates (7-11) is described, along with their liquid crystalline behaviour which was characterised by thermal optical microscopy and differential scanning calorimetry. An unusual observed texture is obtained on cooling (7-11) from the isotropic liquid, which had not been recognisable as any known mesophase type, but exhibited many of the characteristics of a crystalline solid separating from the isotropic liquid. The nature of this mesophase type has been investigated by extensive miscibility studies and has been determined to be that of the smectic crystal G phase.

 

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The synthesis of four series of 4'-n-alkylbiphenyl-4-yl 4-n-alkylbenzoates (17), is also described. Compounds of this type had been previously cited in a patent granted to Steinsträsser et al.44 although no attempt had been made by the authors to identify the smectic phases present. A discussion of the characterisation of the liquid crystalline behaviour of these homologous series by thermal optical microscopy and differential scanning calorimetry is given. 

These esters exhibit extensive smectic polymorphism and a comparison of their mesophase behaviour and thermal stability with that of the analogous 4'-n-alkylbiphenyl- 4-yl 5-n-alkylthiophene-2-carboxylates (20) reported by Butcher et al.45 is given.

 

In recent years, much attention has been drawn to the relatively new subject area of metallomesogens (metal -containing liquid crystals). A great deal of success has been reported utilising either ferrocene-1,1'- (47) or -1,3-dicarboxylic acid (75). The preparation of several novel 1,1'-disubstituted ferrocene compounds is reported in an attempt to synthesise novel ferrocene metallomesogens, which were not derived from either of the afore mentioned systems. Although non of the compounds proved mesogenic, an indication as to the possible effect of the central linking group, X, on the thermotropic behaviour of some l,1'-bis(4'-n-alkyl(oxy)biphenyl-4-yl)ferrocenes (33), (59), (61), and (67) is given. The preparation of a novel mono-substituted ferrocene (60) and two other l,l'-di-substituted ferrocenes (70), (72) is also reported.

 

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Synthesis and properties of some novel liquid crystalline systems including metallomesogens.

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