Macrocycle- And Cage-Based Ligands And Their Self-Assembled Multi-Pore And Multi-Cavity Supramolecular Architectures

Beyond traditional molecular chemistry,supramolecular self-assembly focuses on generating highly complicated and well-defined structures by non-covalent interactions.With the development of the supramolecular field,construction of supramolecular supramolecular architectures via coordination-driven self-assembly has received significant attention.[2,2’:6’,2’’]-Terpyridine（tpy）is a polydentate ligand with good coordination.<tpy-M^II-tpy>(M=Ru²⁺,Zn²⁺,Fe²⁺,Cd²⁺,etc)connectivity has been widely used to construct different 2D and 3D metallosupra-architectures.However,the preparation of multi-pore and multi-cavity supramolecular structures is challenging and requires precise control of the ligand geometrical configuration and coordination sites.This thesis work focuses on the construction of multi-pore size and multi-cavity supramolecular structures based on terpyridine-based ligands and transition metal ions:（1）Two hexaruthenium macrocycle-based metallo-organic ligand L1 and L2 were designed and successfully synthesized by a stepwise strategy,which contained two and four free coordination sites,respectively.When L1 and L2 were assembled with Zn ^IIions,only tetrapod-functionalized hexagon with reinforced connections successfully assembled to generate a tessellated square array Zn₈L2₄,providing evidence that bridges can make a difference.The discrete Zn₈L2₄can be assembled into multichannel tubular nanostructures through the molecular packing.The presence of three different kinds of pores,one central tetragonum（Zn₄）,four corner hexagon（Ru₆）,four side irregular hexagon（Ru₂Zn₂）made it possible to provide novel macrocyclic host systems for shape-,size-,and charge-selective guests.（2）Two"three-clawed"terpyridine ligands L3 and L4 that containing organic molecule cages were successfully synthesized,with L3 ligand connected to terpyridine at m-benzene position and L4 ligand connected to terpyridine at m-thiophene position.In further self-assembly studies with metal Zn²⁺,L4 failed to achieve the next ideal assembly step,while L3 successfully assembled into a tetrameric structure with multi-cavity cage Zn₆L3₄,indicating that ligands at the right angle is required to self-assemble with the metal ion to form a stable discrete structure.The tetrameric multi-cavity cage structure formed here has two different sizes of cavity cages:four small organic molecule cages and a large cavity metal-organic molecule cage in the middle.This work provides a new idea for the synthesis of complex multi-cavity caged 3D structures.