Platinum Metallacycles-based Luminescent Materials

Supramolecular interactions are the key to the high complexity and functionality of complex and functional molecular assemblies,leading to the emergence of new materials.Self-assembly is a common strategy for construction of supramolecular structures via small molecular building blocks.Among the various strategies of self-assembly,coordination-driven self-assembly(CDSA)is one of the most powerful and influential strategy.By selecting appropriate metal ions and rationally designed building blocks,metal-organic complexes(MOCs)with different sizes,shapes and metal(M)/ligand(L)ratios can be obtained by coordination-driven self-assembly.So far,platinum metallacycles and platinum metallacages with various geometric shapes and sizes have been widely reported.They were wildly used in supramolecular catalysis,information storage,energy transfer,biosensing and imaging,supramolecular free radicals and other fields.However,there are few reports on the host-guest molecular recognition of highly discrete and dynamic platinum metallacycles,which limits the application of platinum metallacycles in luminescent materials.This thesis will focus on this limitation,mainly including the following four parts.In the first part,we mainly review the design and synthesis of platinum metallacycles,and the application of platinum metallacycles in light-harvesting systems,detection and recognition,supramolecular catalysis,luminescent materials and biomedical fields.In the second part,we designed and synthesized benzyl-modified platinum metallacycles M1,naphthalene-modified guest molecules G1 and G2,and studied the host-guest chemistry of M1 with G1 and G2,respectively.It was found that M1 has good host-guest interaction with naphthalene derivatives,and quasirotaxane M1G1 can be constructed by one-pot method.Due to the dynamic reversibility and discreteness of M1,[2]rotaxane M1G2 can also be constructed by one-pot method.M1G2 has good aggregation-induced emission characteristics and can be used as an excellent donor for light trapping systems.Eosin(ESY)and nile red(Ni R)were selected as the first and second energy acceptors,respectively,to construct a continuous two-step energy transfer process in aqueous solution.In the third part,we designed and synthesized cyanoethylene modified platinum metallacycles M2,which has good aggregation-induced emission characteristics and can be used as a donor for light capture system.Since the absorption spectrum of Eosin(ESY)has a good overlap with the M2 emission spectrum,ESY is selected as an energy acceptor to construct a one-step energy transfer process in aqueous solution.In the fourth part,we designed and synthesized a bipyridine ligand L3 with acridone as the backbone.L3 and 180° biplatinum acceptor were coordinated to drive selfassembly to obtain platinum metallacycles M3,which showed solvent discoloration effect.