Three series of amphiphilic mesogens consisting of a cyanostilbene with different central condensed rings as it-conjugated aromatic unit, three lipophilic alkyl chains at one terminal and one glycerol group at the other terminal were constructed by using Suzuki coupling and Knoevenagel reactions. The type of central condensed ring had a great influence on the liquid crystalline self-assemblies, solvatochromism and aggregation-induced emission. The amphiphilic mesogens containing central phenyl could exhibit a mesogenic transformation from cubic mesophase with Ia3d lattice to rectangular columnar mesophase with p2 mm lattice. The amphiphilic mesogens containing central naphthyl could exhibit a mesogenic transformation from cubic mesophase with Ia3d lattice to hexagonal columnar mesophase. Whereas, the amphiphilic mesogens containing central anthryl could exhibit a transition from non-liquid crystal to monotropic hexagonal columnar mesophase. The distinct difference in mesogenic transition might be assigned to the steric hindrance induced by the central core and the length-to-breadth ratio of rigid core. All the amphiphilic mesogens display positive solvatochromic phenomenon and the solvatochromism is in the order phenyl amphiphilic mesogens < naphthyl amphiphilic mesogens < anthryl amphiphilic mesogens due to the gradually increased intramolecular charge transfer which could be observed by the HOMO and LUMO distributions. The phenyl and naphthyl amphiphilic mesogens exhibit weak fluorescence in solution but high fluorescence in aggregated state (aggregation-induced emission enhancement), whereas the anthryl amphiphilic mesogens exhibit extremely high fluorescence in both solution and aggregated states owing to different core structures. Therefore, tuning the it-conjugated aromatic unit of amphiphilic mesogens would induce interesting multidimensional mesophases and photoelectrical properties, which would be beneficial to construct multifunctional mesogens.
[1]Kunming Med Univ, Sch Forens Med, NHC Key Lab Drug Addict Med, Kunming 650500, Yunnan, Peoples R China.
[2]Univ Elect Sci & Technol China, Mianyang Cent Hosp, Sch Med, NHC Key Lab Nucl Technol Med Transformat, Mianyang 621099, Sichuan, Peoples R China.
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