Near-IR Phosphorescent Ruthenium(II) and Iridium(III) Perylene Bisimide Metal Complexes

The phosphorescence emission of perylene bisimide derivatives has been rarely reported. Two novel ruthenium(II) and iridium(III) complexes of an azabenz-annulated perylene bisimide (ab-PBI), [Ru(bpy)(2)(ab-PBI)][PF6](2) 1 and [Cp*Ir(- ab-PBI)Cl]PF6 2 are now presented that both show NIR phosphorescence between 750-1000 nm in solution at room temperature. For an NIR emitter, the ruthenium complex 1 displays an unusually high quantum yield (Phi(p)) of 11% with a lifetime (tau(p)) of 4.2 mu s, while iridium complex 2 exhibits Phi(p)<1% and tau(p)=33 mu s. 1 and 2 are the first PBI-metal complexes in which the spin-orbit coupling is strong enough to facilitate not only the S-n -> T-n intersystem crossing of the PBI dye, but also the radiative T-1 -> S-0 transition, that is, phosphorescence.