双氟取代苯和联苯类液晶化合物的量子化学研究

运用AM1和PM3两种SCF-MO方法,通过能量梯度全优化计算,给出了对一系列环上双氟取代苯、联苯液晶化合物的稳定几何构型、电子结构和分子基本性质(生成热、偶极矩、前沿分子轨道能级等)。联系有机结构理论进行了分析和讨论。初步阐明了其分子结构与介电各向异性之间的关系,为设计和开发新型液晶分子研究提供了有较大价值的线索。

Quantum-chemical studies on difluoride-substituted phenyl and biphenyl series crystal compounds

AM1 and PM3 SCF-MO calculation have been performed to obtain moleculer geometries of difluoride-substituted phenyl and biphenyl series liquid crystal compounds by energy gradient completed optimization.For all optimized configurations,there is no imaginary frequency in vibrational analysis.The stable configuration,electronic structure,and some molecular properties of title compounds(heat of formation,dipole moment and energy level of frontal molecule orbital,etc.) are first reported.The calculated results are fully discussed with respect to the organic structure theory.It was illuminated preliminary that relation between the dielectric anisotropy and molecule structure,which will provide a clues for the research of the new liquid crystal molecule.