端基含108个己氧基偶氮苯介晶基元三代树状碳硅烷液晶研究

Studies on a Carbosilane Liquid Crystalline Dendrimer of the Third Generation Containing 108 4-Hexyloxyazobenzene Mesogenic Groups in Periphery

用发散法合成以四碳硅烷为核心 ,周边含 10 8个己氧基偶氮苯介晶基元 ( M3)端基的三代树状碳硅烷( D3)液晶 ,并用元素分析、核磁共振、激光解吸电离飞行时间质谱、红外光谱、紫外光谱、偏光显微镜、差示扫描量热 ( DSC)和 X射线衍射法 ( WAXD)进行表征 .D3为向列相液晶 ,与 M3相同 ,三代 ( D3)、二代( D2 )和一代 ( D1)树状物的相态由介晶基元的相态决定 .D3的液晶态相行为是 K79N136 I132 N,D3的熔点比 M3的低 19℃ ,D3的清亮点比 M3的增加 16℃ ,D3液晶态温区比 M3宽 35℃ .

The divergent synthesis of a new carbosilane liquid crystalline(LC) dendrimer of the third generation(D3) was discribed. One hundred and eight 4-hexyloxyazobenzene groups were used as mesogenic fragments and attached in periphery and four carbosilane as the core. The structure and properties of D3 were characterized by elemental analysis, 1H NMR, MALDI-TOF-MS, IR, UV-Vis, polarizing optical micrograph, DSC and WAXD. D3 is a nematic liquid crystal, which is the same as M3.The mesomorphic behaviour of the dendrimer depends on that of the mesogenic units. The phase behavior of D3 is K79N136I132N. The melting point of D3 is 19 ℃ lower than that of M3, and the clearing point of D3 is 16 ℃ higher than that of M3 and the mesophase region of D3 is 35 ℃ wider than that of M3.