Construction Of Chiral Supramolecular Compounds By Second-sphere Coordination:Synthesis,Structure And Effect Of Methyl Group’s Position On Chirality

In recent years,supramolecular chemistry is becoming a hot research field.Especially,the study of chiral supramolecular comopounds is particularly extensive,which is not just limited into the synthesis of chiral molecules alone,but also focused on the preparation of chiral compounds through chiral recognition and molecular interaction.Recently,much attention has been paid to second-sphere coordination chemistry due to its potential use in metal separation and inclusion property.Second-sphere coordination is a kind of non-covalent interaction between organic ligand and metal complex anion,thus in essence it’s a supramolecular self-assembly method.Based on the concept of second-sphere coordinate chemistry,we synthesized a series of complexes,and also studied their properties.In this thesis,two tripod ligands[namely,N,N’,N"-(benzene-1,3,5-triyltris(methylene))trianiline(L1)and N,N’,N"-((2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene))tris(4-methylaniline)(L2)]were designed,synthesized and characterized by IR,1HNMR,P-XRD.Three achiral crystal[H3L1]3+[MC14]2-·Cl-(M = Zn,Cd,Hg)(crystal 1-3)were prepared by using the traditional solution method based on the concept of second-sphere coordinate chemistry.These three crystals have distinct structures:crystal 1 does not contain water molecules,crystal 2 and crystal 3 contain water molecules,but the water molecules are connected with other components through Van der Waals’ force in crystal 2,whereas the water molecules are hydrogen bonded with L1 in crystal 3.Chiral crystal[H3L2]3+[MC14]2-·Cl-(M＝Zn,Cd,Hg,Co)(crystal 4-7)were prepared by using the traditional solution method based on the concept of second-sphere coordinate chemistry.These four crystals all belong to chiral space group and have the same helical structure along c axis.The methyl substitutent group’s position in the ligand can have influence on the crystal chirality.Density functional theory(DFT)calculations were carried on the ligand L1 and L2 to explain their differences on thirality.In summary,we designed and synthesized two ligands L1 and L2,prepared seven supramolecular complexes,and discussed methylic position’s impact on crystal chirality.