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

The weakly coordinating cluster [CB11H12]− is used as a versatile building block for the preparation of luminescent copper(I) complexes. Treatment of [CB11H11‐12‐C≡CH]− with CuI and ammonia affords {(CB11H11‐12‐C≡C)2Cu4(NH3)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