Atomically Defined Monocarborane Copper(I) Acetylides with Structural and Luminescence Properties Tuned by Ligand Sterics

The weakly coordinating cluster [CB 11 H 12 ] − is used as a versatile building block for the preparation of luminescent copper(I) complexes. Treatment of [CB 11 H 11 ‐12‐C≡CH] − with CuI and ammonia affords {(CB 11 H 11 ‐12‐C≡C) 2 Cu 4 (NH 3 ) 3 } n ( 2 ). Addition of selected phosphine and pyridine ligands transforms 2 to a range of homometallic products 3 – 13 . All compounds have been characterized by X‐ray crystallography, which reveals a surprising variety of structural complexity featuring cores with two to ten Cu + centers. In the solid state, products 3 – 13 exhibit room‐temperature phosphorescence across the visible spectrum in colors from blue to deep red. Lifetimes at room temperature are in the microsecond regime, and quantum yields of up to Φ=0.99 are observed.