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Journal of the Korean Chemical Society (JKCS)

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

Syntheses and Liquid Crystalline Properties of the Compounds Having a Siloxylethylene Group and a Terminal Substituent

Siloxyl Ethylene 그룹과 말단치환기를 포함하는 액정화합물의 합성 및 액정성
Seong Hun Yang, Wan Hae Hong, Euy Kyung Yu

Diethylenedisiloxy 유연격자를 갖는 일련의 새로운 액정화합물을 합성하여 이들의 액정특성 및 말단의 페닐기에 para 치환된 치환기들의 스멕틱 그룹 효율성을 조사하였다. 또 말단 그룹의 크기 영향을 알아보기 위하여 para 치환된 페닐 대신 β-naphthyl 그룹을 도입한 화합물도 아울러 합성하였다. 모든 화합물들은 85∼95%의 높은 수율로 합성되었으며, 합성된 화합물들은 모두 양방성 액정 특성을 보여주었다. 이중 X=NO2 화합물은 SA상을 보였고, 나머지 화합물들은 모두 SB상을 보여주었다. 화합물들의 녹음열은 일반적인 액정화합물들과 비교하여 낮은 값을 나타냈으며 등방화열은 비슷한 값을 보였는데, 치환기의 스멕틱 그룹 효율성은 H < CH3 < Cl=NO2 < CN < OCH3 < C6H5 순이었다.

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.

365 - 373
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