A Highly Emissive Cu_2N_2 Diamond Core Complex Supported by a [PNP]^- Ligand

Abstract

A Cu2N2 diamond core structure, {(PNP)CuI}_(2) (2), supported by a [PNP]- ligand (1) ([PNP]^(-) = bis(2-(diisobutylphosphino)phenyl)amide) has been prepared. 2 is highly emissive at ambient temperature in both the solid and solution states and is characterized by a relatively long-lived excited state (τ > 10 μs) and an unusually high quantum yield (φ > 0.65). These observations are consistent with a low degree of structural reorganization between the ground state of 2 and its excited state *2, and also with a high degree of steric protection of the two copper centers of 2 afforded by the bulky [PNP]- ligand. An estimate for the excited-state reduction potential of *2 (ca. −3.2 V vs Fc^(+)/Fc), and the availability of two well-separated and reversible ground-state redox processes, suggests that bimetallic copper systems of these types may be interesting candidates to consider for photochemically driving multielectron redox transformations.