Synthesis And Photophysical Properties Of Pincer Platinum(?)complexes Containing Polymer Chains

As a special kind of phosphorescent materials,pincer platinum(?)complexes have been applied in such fields as chemical sensing and organic light-emitting diodes in recent years due to their unique optical properties.This is because the pincer platinum(?)complexes not only possess the spin-orbit coupling of the d~8 electronic structure,but also because of the?-?stacking interactions and Pt···Pt interactions caused by its unique aromatic ligand plane and plane square coordination structure,which generate the high quantum yield and controllable phosphorescence in the aggregated state.Among various types of platinum(?)coordination complexes,N^N^N type pincer ligands based on 2,6-bis(2-benzimidazolyl)pyridine have been synthesized and investigated thoroughly and extensively.This type of pincer platinum(?)complexes has a strong phosphor luminescence property.And the structure of 2,6-bis(2-benzimidazolyl)pyridine is easy to modify,which makes it possible for further exploit of the potential properties.In this paper,we have synthesized a variety of polymer composites containing pincer platinum(?)complexes unit based on 2,6-bis(2-benzimidazolyl)pyridine.And we have characterized their structures and photophysical properties by a series of analytical methods.The following parts are the details:Firstly,we have synthesized two series of pincer platinum(?)complexes containing the polystyrene(PS)chains,which the polystyrene chains are combined with the para-position carbon atom of pyridine group,and the nitrogen atom of the benzimidazolyl groups,respectively.The two series of pincer platinum(?)complexes containing polymer chains shows strong phosphorescence properties in both solid and solution states.In addition,these two kinds of pincer platinum(?)complexes could not only self-assemble to form spherical micelles with the pincer platinum(?)coordination unit as the corona and the PS chains as the core in the mixed solvents of tetrahydrofuran/methanol,but also show a luminence enhancement and the contraction of the micelle volume with the increasing methanol content under the same concentration of the platinum(?)complexes.Secondly,we synthesized another two series of pincer platinum(?)complexes containing polyethylene glycol chains(PEG),which have good solubility in water and can show strong phosphorescence emissions in solid states and aqueous solutions.The physical properties of this type of pincer platinum(?)complexes in solid states also change with the increase of the PEG chains.Therefore,we have characterized the thermodynamic properties and microstructures of the two series of complexes,on which we discussed the effect of the increase of polymer chains on the ordered structure of the pincer platinum(?)complexes containing PEG chains.