Dinuclear Coinage-Metal Complexes of Bis(NHC) Ligands: Structural Features and Dynamic Behavior of a Cu–Cu Complex

Abstract

Binuclear complexes of copper, silver, and gold bearing a 2,2′-bipyridine analogue, the pyridazine annelated bis(N-heterocyclic carbene) ligand (vegi) 1, were prepared and structurally characterized. They all feature the shortest metal− metal distances that have been measured so far in complexes with this structural motif bearing neutral bidentate ligands, indicative of d 10 −d 10 interactions. While in the silver complex the linear coordination of each silver atom with two carbene ligands results in a planar complex, the ligand planes are twisted by 70°in the Cu complex 4 and by 31°in the gold complex 3. The copper complex shows a solvent-dependent equilibrium between the [Cu 2 L 2 ] 2+ complex and a [Cu 2 L 3 ] 2+ complex along with solvated CuPF 6 .

Molecular Rearrangement of Trinuclear Cu(I)‐NHC: Synthesis of Mono, Binuclear and Polymeric Cu(I)‐NHCs

“…They explored the molecular rearrangement of polymeric Cu(I)‐NHC to dimeric Cu(I)‐NHC in presence of amine or imidazole. In this direction, Doris Kunz's group reported a solvent‐dependent dynamic behaviour of Cu(I)‐NHC complex, in which [Cu 2 (vegi Bn ) 2 ] 2 + and [Cu 2 (vegi Bn ) 3 ] 2 + remain in equilibrium in coordinating solvents like CH 3 CN . Thus, an innovative idea has been applied for the synthesis of NHC stabilized Cu(I) coordination polymer using trinuclear Cu(I)‐NHC assembly 1 as Cu(I) precursor and some linear bridging co‐ligands.…”

Synthesis, Characterization and Luminescence of Gold Complexes Bearing an NHC Ligand Based on the Imidazo[1,5‐a]quinolinol Scaffold

“…[4][5][6] Those bearing ligands with huge π systems and energetically low-lying excited ππ* states feature intense intraligand (IL) emissions. [7][8][9] However, Au III with its low-lying dd states causes effective quenching of the excited state, thus diminishing or even preventing luminescence. [10] Therefore Au III complexes are only emissive if strong ligands destabilize these dd states thereby hampering radiationless deactivation.…”

Dinuclear gold (I)‐di‐N‐heterocyclic carbene complexes: syntheses, structure, density functional theory calculation and photoluminescence study

“…1 H‐NMR spectra of complexes 1–8 show only marginal differences of the chemical shifts compared with the spectra of silver (I)‐NHC complexes i−viii , [ 11 ] with only slight shifts (about ~0.03 ppm) due to the different metal ions attached. [ 17 ] In the 13 C‐NMR study, no obvious changes were observed in the spectra of 1–8 compared with the spectra of i−viii , except that sharp singlet peaks at 190.00–192.00 ppm were assigned to the presence of carbene carbon C2’ that bonded to gold (I) ions, [ 18 ] instead of doublet peaks (about 187.00–190.00 ppm) in the spectra of i−viii belonging to C2’‐Ag (I) [ 11 ] (Figure 1; Supplementary S2 in ESI†).…”