Synthesis And Electrochromic Pro Perties Of Bisterpyridine-based Metallo-supramolecular Polymers

In recent years,a new type of electrochromic material—metallo-supramelecular polymers—has attracted attention and showed advantages as both organic electrochromic materials of processability and multi-color and inorganic electrochromic materials of high stability.In this paper,we prepared several bisterpyridine-based metallo-supramolecular polymers and studied their electrochromic properties in detail.1.Three kinds of bisterpyridine-based metallo-supramolecular polymers named FeL?CoL and RuL respectively were prepared.The results indicate that the metal ion and the ligand connected to each other alternately as a stoichiometric ratio of 1:1 to form the polymer.FeL and RuL exhibit excellent electrochromic properties due to the strong MLCT(metal-to-ligand charge transfer)absorption,with high optical contrast(?T>60%),fast response time(less than 2s),high coloration efficiency(more than 200 cm2/C)and distinct color change(FeL:blue(?)transparent;RuL:red(?)transparent).Because of the weak d-d*transition absorption,the CoL shows poor electrochromic properties.2.A series of Fe/Ru-based bimetallo-supramolecular polymers were synthesized by stepwise complexation of the metal ions to the ligand.The results show that the Fe ions and Ru ions were alternately introduced to the polymer chain,and there exist shifts of the oxidative or the reductive potential of the CV,which are induced by the electronic interaction between the neighbouring metal ions.Electrochromic measurements present that changing the ratio of metal ions of the bimetallo-supramolecular polymers can enrich the color variation of the polymers,which can realize blue,red,orange,light green,transparent and other colors.In addition,the polymers show good electrochromic properties with fast response time(less than 2s),high optical contrast(AT=67%@583nm)and high coloration efficiency(258.2 cm2/C@583nm and 262.2 cm2/C@503nm).3.A series of Fe/Co-based bimetallo-supramolecular polymers with different ratio of metal ions were prepared.The results show that the Fe ions and Co ions do not perfectly arrange alternately in the polymer chain.By changing the metal ions ratio and applied potential,the polymer films can realize a series of color change including blue,purple,dark orange,orange,light yellow,transparent and other colors.