π-Conjugated phosphole derivatives: synthesis, optoelectronic functions and coordination chemistry

pi-Conjugated organophosphorus derivatives have recently emerged as valuable building blocks for the tailoring of functional molecular materials. We have focused for ten years on the synthesis of phospholes bearing aromatic 2,5-substituents (phenyl, thienyl, pyridyl, etc.) and used these compounds as materials in fields as diverse as OLED's, WOLED's, non linear optics. Their properties (such as optical and electrochemical behaviour, thermal stability) can be finely tuned by functionalization at the P atom. Phosphole-based polymers have also been prepared by electropolymerization and have been used as sensors. More recently, phospholes substituted by one or two pyridyl groups have proven to act as multidentate ligands with original coordination properties. A diversity of supramolecular rectangles that stacked into columns in the solid state has been obtained, opening new perspectives in the coordination-driven supramolecular organization of pi-conjugated systems. Chiral pi-conjugated phospholes having a helical moiety have also been synthesized and spatially organized by using coordination to metallic ions, giving rise to sophisticated chiral complexes.