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

The weakly coordinating cluster [CB11 H12 ]- is used as a versatile building block for the preparation of luminescent copper(I) complexes. Treatment of [CB11 H11 -12-C≡CH]- with CuI and ammonia affords {(CB11 H11 -12-C≡C)2 Cu4 (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.