Synthesis of Re(I) complexes bearing tridentate 2,6-bis(7′-azaindolyl)phenyl ligand with green emission properties

The Re(I) complexes bearing 2,6-bis(7′-azaindolyl)phenyl ligand as a tridentate ligand were synthesized by treatment with Re2(CO)10. The structures of the complexes were confirmed by X-ray crystallography. Both 7-azaindolyl ligands of Re(I) complexes are present in butterfly forms. The Re–Cipso bonds showed a partial double bond character by π back-donation between the phenyl moiety and Re atom. In THF solution at room temperature, these complexes exhibited green emission (λem=510 nm), which is considered to be attributable to MLCT (dz2(Re) →π* (7′-azaindolyl group)) transition containing π→π* (7′-azaindolyl group) transition.