Rigid Phenylene Ethynylene Units Linked by A V-shaped Centre. An Approach to Biaxial Nematogens?
作者:Matthias Lehmann、Jérémy Levin
DOI:10.1080/15421400490435260
日期:2004.1
theoretical predictions that nematic phases formed from V-shaped compounds could be biaxial, shape-persistent phenylene ethynylene arms linked by 1,3-phenylene, 4,4′-diphenylenemethane and 3,6-fluorenone units have been synthesised. Crystallisation and micro-segregation is prevented by 2,5-alkoxy substitution on the middle benzene ring of the arms. The specific molecular engineering, i.e. variation
2-Bromo-5-iodo-hydroquinone dialkylethers are prepared by the stepwisehalogenation and alkylation of hydroquinone monoalkylethers using simple and easily performable reactions. Boron tribromide induced cleavage of the dipropoyl ether gives the parent compound 2-bromo- 5-iodo-hydroquinone in good yields.