ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 40, Number 5
JKCSEZ 40(5)
October 20, 1996 

A series of new dimesogenic compounds, di-4-(p-substituted phenoxycarbonyl) phenoxyethyltetramethyldisiloxanes, were prepared and identified. Another compound having a β-naphthyl group in the place of a p-substituted phenyl ring was also synthesized. The results were as follows, 1) The compounds were synthesized with considerably high yields in the range of 85% to 95%. 2) All of the compounds are enantiotropic and form smectic phase in melt, the compound with X=NO2 is SA while the remaining ones are SB. 3) Liguid crystalline phase transion of the compounds were influenced in corporations of the size and electron affinity of the substituent. 4) The heats of melting ΔHm, are particulary low, while the heats of isotropization, ΔHi, are comparable to other dimesogenic compounds. 5) The smectic group efficiency of the substituents in the compounds is in the order of H < CH3 < Cl=NO2 < CN < OCH3 < C6H5.