The Construction And Application Of Homochiral Metal-organic Framework Modified By Amino Acids

Chirality is the most common phenomenon in the nature.The two enantiomeric forms may have completely different biological,pharmacological and physiological activity.So it is particularly important to synthesize enantiopure compounds.The excellent performances of homochiral metal-organic frameworks compounds in asymmetric catalysis and enantiomeric separation make them ideal materials for the preparation of enantiopure compounds.In this thesis,two pairs of homochiral MOFs were constructed by modifying the aromatic carboxylic acid ligands with cheap and readily available chiral amino acids,and their applications in asymmetric catalysis and enantiomeric separation were studied.The main contents are as follows.(1)A pair of homochiral MOFs(Co-PIA1/Co-PIA2)were hydrothermally synthesized by the reaction of cobalt ion,NH2-4,4'-bipyridine and chiral aromatic carboxylic acid ligands L/D-H3 PIA modified by proline.Their structures were characterized and their application in the synthesis of chiral cyclic carbonates and enantiomeric separation were also studied.The catalytic experiments showed that the synergistic effect of the potential Lewis acid sites and amino groups allowing Co-PIAs to catalyze the reaction efficiently(yield of 76.32% and ee of 79.75%).The results of enantioseparation showed that Co-PIAs had certain separation effect for racemic 1-phenylethyl alcohol,1-phenylethylamine and methyl-mandelate.(2)A pair of homochiral MOFs(Zn-BIA1/Zn-BIA2)were hydrothermally synthesized by reaction of zinc ions,4,4'-bipyridine and the chiral aromatic carboxylic acid ligands L/D-H3 BIA modified by alanine.Their structures were characterized and the application of them in asymmetric cyanosilylation and enantioseparation were also studied.The catalytic experiments showed that the synergistic effect among the Lewis acid sites from the unsaturated Zn(II),the Lewis base sites from the uncoordinated carboxylate oxygen atoms making Zn-BIAs catalyze the reaction with high efficiency and good enantioselectivity at room temperature(yield of 98%,ee of 88%).The results of enantioseparation showed that the separation effect of Zn-BIAs on racemic 1-phenylethanol,1-phenylpropanol and methyl-mandelate was better than that of Co-PIAs because of the abundant chiral and supramolecular sites in the structure of Zn-BIAs.