Synthesis Of The Bow-shaped Liquid Crystal Molecules

Since NioriT et al have firstly reported the synthesis of bent-core liquid crystals and found their special electro-optic property(ferroelectric and antiferroelectric switching),their potential applications attracted a lots researchers and arosed a heat wave of bent-core liquid crystal in the international liquid crystal field.The bent-core liquid crystal can form into new-type liquid crystal phase.The most attractive property is their superstructural chirality in liquid crystal(LC) phases of achiral molecules.The observation of switching of the chirality sense in these systems by external fields are of potential scientific application.At the present,there are few reports about bent-core liquid crystals,herein we report the synthesis of a new kind of bent-core molecules.Therefore,starting from accessible materials,a series of novel bent-core molecules,which are composed of 2,8-dibromo-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine as the central bend core and dodecyl alkoxy groups as the terminal flexible chains as well as different rigid arm chains are synthesized in reasonable yields via esterification as key step.Starting from p-bromoaniline,we synthesized the∧-type molecule 2,8-dibromo-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine.Compound 2 2,8-di(p-hydroxy-phenyl) -6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine can be obtained from demethylation of 2,8-di(p-methoxyphenyl)-6H,12H-5,11-methanodibenzo[b,f][1,5]-diazocine which was synthesized by Suzuki coupling reaction between 2,8-dibromo-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine and p-methoxyl-phenylboronic acid.Then starting from methyl p-hydroxy benzoate,acrossing a series of alkylation,esterification and the oxidation of aldehyde group we got the compound 4 C₁₂H₂₅O-C₆H₄-COO-C₆H₄-COOH.Target molecule 1 was obtained by esterification between 2 and 4,1' was also obtained between 2 and C₁₂H₂₅O-C₆H₄-COOH in the same way.