Zhaokui Jin

Asymmetrical phenyldiacetylenes liquid crystalline compounds with high birefringence and characteristics of selective reflection

A series of asymmetrically disubstituted liquid crystalline compounds with high birefringence based on phenyldiacetylenes was synthesised by coupling of intermediate molecules with a phenylacetylene fragment. The structures of the intermediates and resulting compounds were confirmed by Fourier transform infrared, 1H nuclear magnetic resonance and Matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Their liquid crystalline behaviour, including transition temperatures and phase sequences, was investigated by differential scanning calorimetry and polarising optical microscopy. As an important parameter, the birefringence was also measured, using polarising light interferometry. The results indicated that the compounds exhibited different liquid crystalline phases in the high temperature region, with high birefringence values. In addition, the selective reflection characteristics associated with birefringence under conditions which maintained the matrix nematic liquid crystal and the concentration of chiral dopant were studied.

Synthesis and Third-Order Nonlinear Optical Properties of Triphenylene Derivatives Modified by Click Chemistry

A series of asymmetric triphenylene derivatives containing typical D-π-A structures is successfully synthesized by means of [2+2] cycloaddition-cycloreversion click reactions. The photophysical and electrochemical properties, as well as the click reactions, are characterized by means of UV/Vis absorption spectroscopy, cyclic voltammetry, and DFT modulations. In addition, the third-order nonlinear properties, including the nonlinear absorption and the nonlinear susceptibilities, are investigated by using Z-scan techniques. A typical reverse saturable absorption-saturable absorption behavior is observed for the third-order nonlinear absorption, with the third-order nonlinear susceptibilities of the compounds being 1.05×10(-12) , -1.50×10(-12) , and -0.52×10(-12) esu, respectively.

Disk-shaped symmetric hexa-substituted triphenylene derivatives: Synthesis, physical properties and self-assembly

A series of triphenylene derivatives with six symmetric substituents was synthesized from hexabromotriphenylene. The synthesis was conducted by six-fold palladium-catalyzed Hagihara-Sonogashira cross- coupling reactions to yield the hexa-alkynyl substituted triphenylene derivatives of HTP1, HTP2, HTP3 and HTP4. The six symmetric substituents can not only endow the triphenylene the longer π-conjugated range, but also increase the solubility of the compounds. Their photophysical, electrochemical, thermal properties were investigated respectively. With the comparison of their properties, the structure-property relationships were established which demonstrated the influences of different substituents on the electronic nature and the mesomorphic phase of these disk-shaped molecules. In addition, with the scanning electron microscopy(SEM) and polarized optical microscopy( POM) characterization, the self-assembly behaviors of the compounds were also investigated.