以5-氨基异酞酸为初始原料, 通过酯化、肼解和席夫碱等反应合成了双三齿配体LD, 并通过与锌离子(Zn2+)自组装构筑了金属(锌)-有机大环化合物LD-Zn, 利用紫外-可见光谱、核磁、电喷雾质谱等表征手段研究了LD-Zn对氨基葡萄糖的识别作用。核磁光谱和电喷雾质谱测试表明, 氨基葡萄糖分子能够进入到大环LD-Zn内部, 并且LD-Zn以1∶1的比例包合了氨基葡萄糖分子。紫外-可见光谱表明, 当向LD-Zn中加入氨基葡萄糖后, 373 nm处的吸收峰强度增加, 269 nm和303 nm处的吸收峰强度降低, 平衡常数K达到4.19×103 L/mol, 最低检测限为5.0×10-6 mol/L。通过对比测试发现, LD-Zn只对氨基葡萄糖有紫外光谱响应, 而对葡萄糖和三乙胺无任何响应, 说明氨基葡萄糖的结构与大环化合物LD-Zn的空腔更匹配, LD-Zn对氨基葡萄糖的识别不是单纯羟基(氢键)或者氨基(碱性)引起的, 而是由LD-Zn限域的空腔效应和氨基的氢键协同作用实现了对氨基葡萄糖的识别。

Double-tridentate ligand LD was synthesized by 5-aminophthalic acid through esterification, hydrazinolysis and Schiffs base reactions. Then, a novel metal-organic macrocyclic LD-Zn was built by the assembly of LD and zinc ions for the recognition of glucosamine. The detection mechanism of glucosamine with LD-Zn was studied by UV-Vis, 1H NMR and ESI-MS. The results of 1H NMR and ESI-MS indicate that the glucosamine molecules could enter the LD-Zn. Moreover, 1∶1 stoichiometric host-guest complexation between glucosamine and LD-Zn was formed. UV-Vis spectra show that the intensity of the absorption peak at 373 nm increased significantly after addition of glucosamine into LD-Zn. However, the absorption intensity at 269 nm and 303 nm decreases. The equilibrium constant K reaches 4.19×103 L/mol, and the minimum detection limit is 5.0×10-6 mol/L. For comparison, the detection tests of glucose and triethylamine with LD-Zn were carried out. The UV-Vis spectra do not show any response when glucose and triethylamine are added to LD-Zn. These results indicate that the structure of glucosamine is more compatible with the cavity of the macrocycle LD-Zn compared to glucose and triethylamine. The recognition of glucosamine by using LD-Zn is not attributed to pure hydroxyl(hydrogen bonding) or amino(alkaline), it is mainly caused by the joint effect of confined cavity of LD-Zn molecular and hydrogen bonds of amino.