冰浴法合成席夫碱类化合物及其结构性能研究

【作者】 肖静怡；

【导师】 黄可龙；

【作者基本信息】 中南大学 ， 应用化学， 2008， 硕士

【摘要】 Schiff base取代基团的灵活多变的特性,使其具有重要的化学与生物学意义,一直是化学工作者的研究热点。论文合成了一系列取代芳香醛缩邻苯二胺类缩合双席夫碱化合物,其中四个为新化合物,并对其进行了IR,¹H NMR波谱表征,测定了七种化合物在溶液中以及固态时的紫外吸收光谱和荧光光谱,探讨了席夫碱类化合物分子结构与光谱之间的关系。实验结果表明,水杨醛上的邻羟基是席夫碱类化合物具有荧光性质必要条件;极性溶剂中,苯甲醛邻位和对位上-OH的存在均可引起双席夫碱结构的变化;与固体相比,席夫碱在溶液中的荧光强度较弱,且在317nm和400nm激发下均有荧光发射峰。采用冰浴法合成得到C₂₀H₁₄F₂N₂O₂席夫碱晶体,并对此化合物单晶进行了x射线单晶衍射,在此基础上进一步制备了C₂₀H₁₄F₂N₂O₂Zn配合物,通过核磁共振谱,红外光谱,元素分析等波谱手段对此化合物进行结构表征和分析,并且探讨了其固态和溶液状态的荧光性能。结果表明C₂₀H₁₄F₂N₂O₂席夫碱晶体属于单斜晶系,P2（1）/c空间群,晶胞参数a=6.0938（8）,b=16.347（2）,c=94.474（2）,V=1651.95（4）（?）³,Z=4,Dc=1.417g/cm-³,μ（MoKa）=0.11mm,F（000）=728,T=293 K,R=0.032。配合物以Zn²⁺为中心原子,与席夫碱上的N原子和O原子形成配位数为4的配合物。从双席夫碱出发,合成了一种新型水合双-[2-（2-氯-4-氟苯基）-苯并咪唑],并对此化合物单晶进行了x射线单晶衍射,并通过薄层色谱对反应机理进行研究。结果表明,其晶体属于三斜晶系,P1空间群,晶胞参数a=7.592（2）,b=7.595（2）,c=11.886（3）（?）,V=574（3）（?）³,Mr=352.33,D_c=1.478g/cm³,μ（MoKa）=0.33 mm^-1,F（000）=262,Z=1,R=0.090,WR=0.209。这种化合物的晶体结构由两个苯并咪唑单分子组成,通过一个水分子连接,与苯并咪唑衍生物的配合物结构相似。发现只有当苯并咪唑邻位不存在-OH时,席夫碱才能进一步关环得到苯并咪唑衍生物。更多还原

【Abstract】 Schiff bases showed important chemical and biological significance because of their flexible characteristics,and have attracted considerable attention of chemists.A series of Schiff bases were synthesized by reacting substituted aromatic aldehydes and primary amines under ice bath,four of which were first reported.The chemical structures of these compounds were confirmed by means of IR and ¹HNMR.The compouds were detected through UV absorption and fluorescence spectrum in solution and solid state,and the relationship between the molecule structure and the spectrum was also studied.The results show that an OH group in an ortho- position in the salicylaldehyde is the necessary condition of schiff base compounds which possess strong fluorescence properties;In the polar solvent,the exist of an OH group in an ortho or para position can cause the change of structure of bis-schiff bases; compared with the solid state,the schiff base’s fluorescence is weaker when in the solvent and exhibits emission in the 317nm and 400nm.In this study,the title compound was synthesized by reactions of the o-phenyldiamine with 5-F-salicylaldehyde under ice bath.Its structure has been investigated by X-ray single crystal diffraction.It reveals that the compound belongs to monoclinic P2（1）/c space group,a=6.0938（8）, b=16.347（2）,c=94.474（2）,V=1651.9（4）,Z=4,D_c=1.417andμ=0.11. The Zn（Ⅱ）complex has also been prepared and characterized by the analytical and spectroscopic methods.According to the characterization data,the structure of the complex was interpreted and its fluorescence properties was also investigated.Bis-[2-（2-chloro-4-fluorophenyl）-1H-Benzimidazole]-hydrate has been synthesized from bis-Schiff base.The results determined by XRD reveals that the complex crystallizes in Triclinic,space group P1,with a =7.592（2）,b=7.595（2）,c=11.886（3）（?）,V=574（3）（?）³,M_r=352.33,D_c =1.478g/cm³,μ（MoKa）=0.33 mm^-1,F（000）=262,Z=1,the final R= 0.090 and wR=0.209.The crystal structure is formed with two benzimidazole molecules,which are linked by a water molecule as center, similar to the complex of benzimidazole.The reaction mechanism was also discussed by changing reaction conditions.It is demonstrated that benzimidazole can only be formed from Schiff base effectively when o-hydroxyl group does not exist in benzaldehyde.更多还原