Dinuclear silver(I)‐ and gold(I)‐ N heterocyclic carbene complexes; Synthesis, structural characterizations, photoluminescence and theoretical studies

Herein, a new family of cationic Ag(I)- and Au(I)-, complexes ligated to a novel C∩N donor N- heterocyclic carbene (NHC) ligand 3-methyl-1-(1-methyl-2-methylbenzoyl)imidazolin-2-ylidene, (1) are described. Compound 3-methyl-1-(1-methyl-2-methylbenzoyl)imidazolium hexafluorophosphate (1.HPF₆) essentially serves as a carbene precursor that delivers the NHC carbene to Ag(I) and Au(I). The corresponding complex [{Ag(1)}{PF₆}]₂,(2), was prepared using mild base Ag₂O and 3-methyl-1-(1-methyl-2-methylbenzoyl)imidazolium hexafluorophosphate (1.HPF₆). Transmetallation method was capitalized to synthesize [{Au(1)}{PF₆}]₂,(3). All the novel compounds were characterized by elemental analysis, ¹H NMR, ¹³C NMR, HR mass spectroscopic studies, and finally by single crystal X-ray studies. X-ray crystallographic studies revealed that the dinuclear complex 2 and 3 adopt linear geometry (C_carbene-Ag/Au-N_imi) where strong Ag–Ag and Au–Au interaction present. The structural assignments were further supported by DFT calculations. TDDFT studies have been performed to inside into the electronic properties.