Rigid Backbone Conjugated Phenylene/Bipyridine Polymers: Synthesis of Poly[2,2′-bipyridine-5,5′-diyl-(2,5-dihexyl-1,4-phenylene)

Abstract

The synthesis of the new high-molecular weight polyarylene 3, prepared by cross-coupling of 5,5'-dibromo-2,2'-bipyridine (1) and substituted diboronic acid 2, is described. The number-average molecular weight M n and weight-average molecular weight M w of 3, determined by GPC using polystyrene standards, was 26890 and 77920 g/mol, respectively, with a polydispersity index of 2.90. The slightly yellowish polymer exhibits good solubility in chlorinated solvents like chloroform or tetrachloroethane (TCE), but poor solubility in solvents like THF, 1,4-dioxane, or toluene, In solution and in the solid state (film) it shows an intense blue fluorescence. (Fluorescence quantum yields 85% in 1,4-dioxane, 13.6% in solid state).