X射线单晶衍射研究系列功能七元杂环桥联联苯构象

含有七元杂环桥联联苯的π-共轭聚合物是重要的宽禁带光电材料, 其发光性质决定于两苯环间扭曲角. 利用X射线单晶衍射仪确定了系列功能的七元杂环桥联联苯化合物的晶体结构, 比较了桥联原子, 6,6位取代基及分子间弱氢键对这类桥联联苯扭曲构象的影响. 桥联键是—CH2—O—CH2—和—CH2—S—CH2—的七元杂环桥联联苯两苯环间的扭曲角分别为39°和51°, 在6,6位上含有不同取代基的双氧桥联七元杂环桥联联苯的扭曲角存在5°的差异. 在双氧桥联的七元杂环桥联联苯的二聚物中, 桥联的氧原子与非桥联的苯亚基-苯亚基2,2’位置上的两个氢原子之间形成的氢键网络结构导致中心联苯呈现平面构象, 但氢键并没有改变桥联联苯的构象. 七元杂环桥联联苯的构象主要由桥联原子决定, 同时分子间相互作用亦能轻微调控这类桥联联苯的扭曲角.

Investigation on Conformation of a Series of Functional Bridged Biphenyl Containing Seven-Member Heterocycle by X-ray Single Crystal Diffraction

The π-conjugated polymers and oligomers containing bridged biphenyl were important luminescent materials with wide gap. The luminescent property of these materials was relative to the twisted angle between two benzene rings of the bridged biphenyl. The crystal structures of a series of seven-member heterocycle bridged biphenyls were determined by X-ray diffraction. The effect of the bridged atom, the substituent groups in 6,6-position and hydrogen bond (between bridged oxygen atom and hydrogen atom in 2,2’-position of the center biphenyl) on conformation of the bridged biphenyls was discussed.When the bridged bond (—CH2—O—CH2—) changed to—CH2—S—CH2—, the twisted angle between two benzene rings increased by about 12°. The twisted angle also could be influenced by 6,6-substitaent groups, and the twisted angle might increase by about 5°. The hydrogen bond between bridged oxygen atom and hydrogen atom in 2,2’-position of the center biphenyl didn’t affect the conformation of the bridged biphenyls. The bridged atom played an important role for the conformation of the bridged biphenyl of seven-member heterocyle, and the twisted angle also could be influenced lightly by 6,6-substituent groups.