Synthesis and molecular self-organization of 4-nitro-benxoic acid cholesteryl ester

Staring from 4-nitro-benzoic acid and cholesterol,via esterification under the catalyzed of DCC and DMAP,4-nitro-benzoic acid cholesteryl ester I was obtained in one step.Its mesogenic behavior was investigated by polarizing optical microscopy(POM),differential scanning calorimetry(DSC)and X-ray scattering.Based on the results of the X-ray measurement of the single crystal structure and POM,DSC measurementsof mesophase behavior,target compound I showed the cholesteric mesophase,belonged to cholesteric liquid crystals.Molecular organization model in cholestic phase was established,and the realtionship for molecular packing in crytalline structure and in liquid crystalline struture was analyzed.By comparison,the influence of the substituents on the mesophas behavior of benzoic acid cholesteryl ester derivatives was discussed.