New Star-shaped Mesogens with Three Different Arms on a 1,3,5-Benzene Core
摘要:
The convergent synthesis of new symmetrical and non-symmetrical star-shaped mesogens based on a phloroglucinol core is presented. Molecules with three different arms were derived. via esterification, of various 4-benzoyl-benzoic acid derivatives, substituted with polar groups and n alkoxy chains (n = 1-3), by using a combination of protecting group techniques and stoichiometric reactions. The thermotropic properties were investigated by differential scanning calorimetry, polarised optical microscopy and synchrotron X-ray diffraction. It is found that molecules with more than. seven lateral chains form mesophases. The presence of strong polar groups (-NO2) enlarges the temperature range of the liquid crystal phase. For all studied materials the diffractograms can. be indexed according to a two-dimensional hexagonal lattice. The lattice parameters indicate that the flexible chains are interdigitated.
New Star-shaped Mesogens with Three Different Arms on a 1,3,5-Benzene Core
作者:Matthias Lehmann、Raluca Gearba、Dimitri Ivanov、M.H. J. Koch
DOI:10.1080/15421400490435422
日期:2004.1
The convergent synthesis of new symmetrical and non-symmetrical star-shaped mesogens based on a phloroglucinol core is presented. Molecules with three different arms were derived. via esterification, of various 4-benzoyl-benzoic acid derivatives, substituted with polar groups and n alkoxy chains (n = 1-3), by using a combination of protecting group techniques and stoichiometric reactions. The thermotropic properties were investigated by differential scanning calorimetry, polarised optical microscopy and synchrotron X-ray diffraction. It is found that molecules with more than. seven lateral chains form mesophases. The presence of strong polar groups (-NO2) enlarges the temperature range of the liquid crystal phase. For all studied materials the diffractograms can. be indexed according to a two-dimensional hexagonal lattice. The lattice parameters indicate that the flexible chains are interdigitated.