Metallosupramolecular Polymers Of Platinum(?) Complexes:Self-assembled Structure,Photophysical And Conductive Properties

The square-planar platinum(II)complexes with d~8 electronic configurations exhibit unique spectroscopic,intriguing luminescence and appreciable semiconductive properties.They are driven by tunable Pt…Pt and/or?-?stacking interactions.Based on the above background,we will mainly discuss the following two parts:Firstly,the electrostatic self-assembly of cationic platinum(II)complexes with negatively charged block copolymers in water leads to the formation of fiber-like micelles with a platinum(II)-based ionic core surrounded by a poly(ethylene oxide)corona.The structural details are well documented by various microscopic observations,small-angle X-ray scattering,and wide-angle X-ray scattering.In the fiber-like micelles,the superstrong segregation regime appears unexpectedly,where the half widths of the ionic cores correspond to the lengths of fully stretched anionic blocks.Both the phosphorescent intensities and quantum yields increase remarkably,due to the presence of strong Pt(II)…Pt(II)and?–?stacking interactions.Conductive atomic force microscopy measurements reveal that the individual nanofibers possess recognizable conductivity.The semiconductive behaviors are further supported by electrochemical impedance measurements.The negative slopes obtained from Mott–Schottky plots of1/C~2 versus potential suggest that these nanofibers are p-type semiconductors.However,in the fiber-like micelles,the intense phosphorescence occurs synchronously with the appreciable conductivity.Considering highly available square-planar d~8 transition metal complexes that refer to form metal–metal and?–?stacking interactions,the present strategy represents a novel approach for exploring both intensely phosphorescent and appreciably conductive fiber-like materials.Second,synthesis of two types platinum(II)complexes modified with large polar groups have been synthesized.One type of platinum(II)imidazopyridine complexes containing-phthalazinedione functional group,while the other possesses glutamic acid derivatives.The optical properties of platinum(II)complexes with glutamic acid derivatives were examined by UV-Vis and luminescent emission spectra.It was found that the fluorescent intensity increases with the addition of poor solvents due to the increasing?-?stacking interaction.The results tested by transmission electron microscopy show that the ribbon-like micelles have helical nanostructures.