Unprecedented Efficient Structure Controlled Phosphorescence of Silver(I) Clusters Stabilized by Carba-closo-dodecaboranylethynyl Ligands

{Ag-2(12-C C-closo-1-CB11H11)}(n) and selected pyridine ligands have been used for the synthesis of photostable Ag-I clusters that, with one exception, exhibit for Ag-I compounds unusual room-temperature phosphorescence. Extraordinarily intense phosphorescence was observed for a distorted pentagonal bipyramidal Ag-7(I) cluster that shows an unprecedented quantum yield of Phi = 0.76 for Ag-I clusters. The luminescence properties correlate with the structures of the central Ag-n(I) motifs as shown by comparison of the emission properties of the clusters with different numbers of Ag-I ions, different charges, and electronically different pyridine ligands.