【摘要】 用X 射线单晶衍射方法测定了液晶化合物2,5-双(4-乙基苯甲酰氯基)苯乙烯(Ⅰ)和2,5-双(4-甲氧基苯甲酰氧基)苯甲醛(Ⅱ)的单晶结构和分子结构.化合物Ⅰ属三斜晶系,空间群P(?),晶胞参数:α=9.356(6)(?),b=9.842(6)(?),c=13.357(8)(?),α=108.68(5)°,β=105.67(5)°,γ=96.36(5)°,Z=2;化合物Ⅱ属单斜晶系,空间群P_n,晶胞参数:α=9.109(2)(?),b=9.187(3)(?),c=23.166(8)(?),β=93.93(2)°,Z=4.在化合物Ⅰ和Ⅱ晶体中,分子均呈伸展构象,分子中的三个苯环平面取向相互成一定的夹角.分子在晶胞中治其伸展方向相互平行堆积,相邻分子的侧链基团(乙烯基,甲醛基)以较短的分子间距4.7-5.6(?)相向排列.化合物Ⅰ晶胞中分子堆积密度比化合物Ⅱ松散.晶体结构分析结果合理地解释了化合物Ⅰ的高聚合性.更多还原

【Abstract】 The crystal and molecular structures of the mesogenic 2,5-bis-（4-ethylbenzoyl）oxystyrene（Ⅰ）and 2,5-bis（4-methoxybenzoyl）oxybenzaldehyde （Ⅱ）have been determined by single crystal X-raydiffraction methods.Both compoundⅠand compoundⅡare liquid crystalline.Crystal data:Compound Ⅰ,C₂H₅·C₆H₄·COO·C₆H₃（CH:CH₂）.OOC.C₆H₄.C₂H₅,triclinic,space group P（?）（No.2）,a=9.356（6）,b=9.842（6）,c=13.357（8）（?）,α=108.68（5）°,β=105.67（5）°,γ=96.36（5）°,Z=2;Compound Ⅱ,H₃CO·C₆H₄·COO·C₆H₃（CHO）·OOC·C₆H₄·OCH₃,monoclinic,space group Pn（No.7）,a=9.109（2）,b=9.187（3）,c=23.166（8）（?）.,β=93.93（2）°,Z=2.In both crystals,the molecules take fully extended form with the long molecular axes of22.7（?） for compoundⅠand of 22.2（?） for compound Ⅱ.The molecules of these two compounds arenot plate-like but rather rod-like.The middle phenyl rings of the molecules rotate from the othertwo phenyl rings by 86.3°and 135.8 for compound Ⅰ;and by 84.9°and 84.7°for compound Ⅱ.Allmolecules are arranged parallel along their long axes in the crystals.CompoundⅠis a polymerizalbe monomer,it easily forms high molecular weight polymer uponheating without any initiators at about 140℃.Its high polymerizability might be explained bythe fact that the molecules are packed such that the lateral vinyl groups of neighbouring moleculesare closely correlated with a distance of only 4.7（?） and the energy-favorable parallel moleculararrangement,which is similar to the arrangement of the mesogens in its polymer.更多还原