Self-sorting Of Alternative Assembly Based On Host-guest Interaction Of Planar Metal Complexes With Cucurbituril

In the past few decades,the fields of photophysics and photochemistry of transition metal complexes have undergone tremendous development.Understanding and exploring the excited state properties and photochemical reactions of these compounds have attracted widespread attention.The compounds of transition metals d⁸ and d¹⁰ show a strong tendency to form non-covalent metal-metal interactions.Unlike d⁶ transition metal complexes,which usually exist in an octahedral geometry,d⁸ and d¹⁰ transition metal complexes have a square planar and linear?or triangular?structures,providing favorable conditions for the existence of metal-metal interactions.The unique physical and chemical properties associated with metal-metal interactions,such as electrical conductivity,photoluminescence,polymorphism,vapochromism,and vapoluminescence,have been attracting extensive research interest and showing potential applications in chemical sensing and supramolecular assembly.Cucurbit[n]uril?CB[n],n=5-8,10?is a class of macrocyclic host molecules.Its unique molecular recognition characteristics make it widely used in catalysis,supramolecular materials,drug delivery and other fields.Our group reported earlier the interesting changes in the photophysical properties of the host-guest complexes formed by the supramolecular host-guest recognition between octahedral and planar terpyridine transition metal complexes and cucurbit[10]uril.In this thesis,a series of d⁸ and d¹⁰ pyridine ligand metal complexes were synthesized,and their changes in photophysical properties before and after recognition with cucurbit[10]uril were studied.The results show that for some metal complexes,the addition of cucurbit[10]uril can significantly enhance metal-metal interactions and?-?interactions.In some cases,the combination of cucurbit[10]uril and the complex can greatly disrupt the formed metal-metal interaction.The host-guest inclusion complex formed by encapsulation of some metal complexes in cucurbit[10]uril is easy to precipitate from the aqueous phase,and the precipitate shows higher fluorescence quantum yield and phosphorescence lifetime.At the same time,the assembly mode of the two-component metal complexes in the water phase was further studied.The results show that the electron-rich ligand metal complex can interact with the electron-deficient metal complex through charge transfer to form an ordered alternative arrangement assembly.Random assembly mode has been found in the assembly of two-component metal complexes with different metals and the same ligand.Not only the addition of cucurbit[10]uril to two-component systems affects the photophysical properties,but also the formed inclusion complexes show interesting self-sorting behavior.