Structural and Spectroscopic Characterization of Trinuclear Ag(I) / Cu(I)-N-Heterocyclic Carbene Clusters of 1,3-bis(2-pyridylmethyl)-1H benzimidazolium hexafluorophosphate
Abstract
1,3-Bis(2-pyridylmethyl)-1H benzimidazolium hexaflurophosphate (1.HPF6) serves as N-heterocyclic carbene bridging agent to prepare trinuclear [(μ-NHC)3Ag3](PF6)3, 2 using mild base Ag2O. The transmetallation of 2 leads to trimetallic species, [(μ-NHC)3Cu3](PF6)3, 3. Complexes 2 and 3 have been characterized by NMR, UV-Vis, and fluorescence spectroscopic studies. Finally, solid-state structures of 2 and 3 have been determined by single crystal X-ray diffraction studies. Interestingly, in both cases the present N-heterocyclic carbene function as bridging (m) ligand holding two metals bearing different M-Ccarbene distances. Both the clusters bear different picolyl bonding connectivity in 2 and 3. The complexes are luminescent at room temperature. DFT studies revealed interactions of metals in the cluster as well as strong interactions of carbene ligand with metals in different extent in 2 and 3.