Recent Advances in Synthesis of Molecular Heteroleptic Osmium and Iridium Phosphorescent Emitters

Abstract

AbstractThe application of new procedures of organometallic synthesis based on alternative starting complexes has given rise to a significant enhancement in the preparation of osmium(IV), osmium(II), and iridium(III) emitters, since 2012. The choice of the precursors should be done taking into account its ligands, since they may cooperate in the emitter synthesis. Three different functions are clearly pointed out in the revised procedures: the ligands of the starting compounds can direct the selectivity of competitive ruptures of σ‐bonds of the chromophores, without having direct participation in the activation; on the contrary, they can directly participate in the generation of a ligand, being a part of the new coordinated group; and the ligands can also act as internal base in σ‐bond heterolytic activation reactions. In addition, the ability of the polyhydrides OsH6(PiPr3)2 and IrH5(PiPr3)2 to activate C−H bonds is pointed out as one of the determining factors of the success in many cases.