A Highly Emissive Cu2N2 Diamond Core Complex Supported by a [PNP]- Ligand

Abstract

A Cu₂N₂ diamond core structure, {(PNP)Cu^I}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.