N‑Heterocyclic Carbene Ligands as Modulators of Luminescence in Three-Coordinate Gold(I) Complexes with Spectacular Quantum Yields

The
first three-coordinate gold­(I) N-heterocyclic carbene (NHC)
complexes have been prepared with the nido-carborane
diphosphine. The complexes are brightly luminescent and present very
high quantum yield values. The carbene ligand is able to modulate
the energy of the emissions and, depending upon the substituent, the
luminescence changes from blue to green. Theoretical calculations
corroborate that the emissions are phosphorescence and arise from
charge transfer (LML′CT) transitions from nido-carborane ligand (L) to metal/ligand group “gold­(I)–NHC
ligand” (ML′).