β-环糊精与水杨酸包合物的合成与结构

Synthesis and Structure of the Inclusion Complex of β-Cyclodextrin and Salicylic Acid

合成了β-环糊精与水杨酸的包合物β-cyclodextrin-salicylic acid(β-CD-sal)[(C42H70O35)2·(C7H6O3)2·(H2O)24],用X射线单晶衍射、元素分析和核磁共振对其分子结构进行了表征.X射线单晶衍射结果表明:包合物的晶体属于单斜晶系,空间群为C2,a=1.9269(5)nm,b=2.4395(7)nm,c=1.6095(4)nm,β=107.816(5)°,V=7.203(3)nm3,Z=4,Dc=1.373g·cm-3,F(000)=3176,R[I>2σ(I)]=0.0971.在形成的2∶2包合物中,β-环糊精通过羟基间的氢键形成头对头的二聚体,两个水杨酸分子以不同的形式与环糊精形成包合物,其中一个水杨酸分子寄居于环糊精的空腔中,而另一个水杨酸则位于由两个环糊精形成二聚体的空隙中.

An inclusion complex β-cyclodextrin-salicylic acid （β-CD-sal） [（C42H70O35）2·（C7H6O3）2·（n2O）24] was prepared between β-cyclodextrin and salicylic acid, and its structure was investigated by X-ray single crystal diffraction, NMR and elemental analysis. The crystallographic study has shown that the inclusion complex belongs to the monoclinic system （space group： C2） with unit cell dimensions a= 1.9269（5） nm, b=2.4395（7） nm, c：=1.6095（4） nm, β= 107.816（5）°, V=7.203（3） nm3, Z=4, Dc= 1.373 gocm-3, F（000）： 3176, R[IS〉2cr（1）]=0.0971. The results show that β-cyclodextrin and salicylic acid form 2 ： 2 inclusion complex in which the fl-cyclodextrins exist as a head-to-head dimer by means of extensive hydrogen bond- ing across the secondary hydroxyl groups and the salicylic acids are included in the dimer in different mode, i. e. one salicylic acid molecule is included in the cavity of the fl-cyclodextrin, and the other is sandwiched in the interface of the dimer.