Platinum(?)-containing Telechelic Metallopolymers:Synthesis,Luminescence And Rheology

Telechelic polymers are defined as linear polymers that only retain physicochemical(or chemical)activity at both ends of the main chain.In recent years,They have attracted much attention because of their unique self-assembled structures and interesting rheological properties originating from various noncovalent interactions,such as hydrophilic-hydrophobic interactions,Coulomb interactions,?-?stacking,hydrogen bond interactions,donor-acceptor interactions,metal-ligand coordination,and special metal-metal interactions.Planar platinum(?)complexes of d~8 electronic configuration have attracted extensive attention due to their interesting spectroscopic and luminescence features.They tend to form Pt(?)··Pt(?)and/or?-?stacking interactions,which further lead to unique metal-metal to ligand charge transfer(~3MMLCT)or excimeric phosphorescent emissions(~3IL).Moreover,such metal-metal interactions can be further used as a novel driving force to assist the construction of hierarchically ordered self-assembled structures with phosphorescent emissions.Therefore,we assume that the planar platinum(?)complexes were modified at both ends of the central polymers,and the unique self-assembly behaviors may occur through Pt(?)···Pt(?)and/or?-?stacking interactions between the planar platinum(?)complexes.Further,Pt(?)···Pt(?)and/or?-?stacking interactions are also used as special associative forces,which will allow telechelic metallopolymers to exhibit unique rheological properties.Therefore,the main contents of this thesis include the following two parts:In the first part of this thesis,two series of platinum(?)complex-containing metallopolymers with different molecular weight polystyrenes as main chains are designed and synthesized.When these telechelic metallopolymers are dissolved in chloroform,~3MMLCT and excimeric emission bands are observed and stemmed from Pt(?)··Pt(?)and/or?-?stacking interactions.In chloroform/methanol mixture solvents with increasing methanol content,~3MMLCT and excimeric emissions are first quenched and then enhanced,and finally the maximum emission bands show slight blue shifts.These platinum(?)-containing telechelic metallopolymers can self-assemble in chloroform/methanol mixture solvents to form flower-like micelles with planar platinum(?)complexes being the cores and polystyrene chains looping into rings as coronas.Moreover,such flower micelles can be further transformed into vesiclelike aggregates with self-assembly time in the mixture solvents of appropriate quality.With increasing methanol content,the metallopolymers self-assemble into single flower-like micelles.It should be highlighted that this class of platinum(?)-containing telechelic metallopolymers can overcome the solvation to form flower-like micelles through Pt(?)··Pt(?)and/or?-?stacking interactions.The second part of this thesis is to study the luminescence behaviors and rheological properties of those platinum(?)-containing telechelic metallopolymers(TPS_n-Pt-I and TPS_n-Pt-II).Both spectroscopic and luminescence studies display that Pt(?)···Pt(?)and/or?-?stacking interactions occur in the solid state of the telechelic metallopolymers,and are further confirmed by using wide-angle X-ray scattering(WAXS).Moreover,the association energies(E_a)of Pt(?)···Pt(?)and/or?-?stacking interactions can be precisely determined using the linear viscoelasticity(LVE)of the associative metallopolymers.This work represents a novel concept in which the planar platinum(?)complexes are modified at both ends of polystyrene chains through click reactions to design and synthesize platinum(?)-containing telechelic metallopolymers.They can self-assemble into special flower micelles and vesiclelike aggregates.New ideas are demonstrated for the preparation of more complex and higher-level nanomaterials with required functions.It is proposed for the first time to quantify the association energies(E_a)of Pt(?)···Pt(?)and/or?-?stacking interactions in the solid state by means of rheological methods.Such quantitative characterization is fundamentally important for understanding Pt(?)···Pt(?)and/or?-?stacking interactions and optimizing device performance for those thin-film and solid applications.This rheological protocol will be generalized to measure other noncovalent intermolecular interactions.Therefore,the subject of this thesis is of great significance for both supramolecular chemistry and metallopolymers.