Heterobimetallic N‑Heterocyclic Carbene Complexes: A Synthetic, Spectroscopic, and Theoretical Study

Publication Date
Journal Title
Journal ISSN
Volume Title
Peer Review Status
Before publication

A new synthetic methodology has been developed for the preparation of heterobimetallic group 11 and group 12 complexes of a symmetrical bis-NHC “pincer” ligand. The synthetic route involved the initial preparation of a mononuclear [Au(NHC)2]+ complex with pendent imidazole moieties on the NHC ligands. Subsequent alkylation of the imidazole groups with Et3OBF4 and metalation with a second metal ion (Ag(I) or Hg(II)) provided two heterobimetallic complexes. Four homobimetallic (Cu(I)2, Ag(I)2, Au(I)2, and Hg(II)2) complexes of the same bis-NHC “pincer” ligand were also prepared. The homobimetallic Cu(I)2, Au(I)2, and Hg(II)2 complexes and heterobimetallic Au(I)−Ag(I) and Au(I)−Hg(II) complexes and the synthetic intermediates for the heterobimetallic complexes were characterized by X-ray crystallography. These X-ray structures show that the bimetallic complexes adopt “twisted” conformations in the solid state, supporting short M···M interactions. Crystalline samples of the homobimetallic Ag(I)2 and Au(I)2 and heterobimetallic Au(I)−Ag(I) and Au(I)−Hg(II) complexes were emissive at room temperature and at 77 K. The geometries of the synthesized complexes were optimized at the M06-L/def2-SVP level of theory, and the electronic nature of the M···M interactions for all synthesized complexes was investigated using natural bond orbital (NBO) calculations.

synthesis, heterobimetallic

Pell, T. P., Wilson, D. J., Skelton, B. W., Dutton, J. L., & Barnard, P. J. (2016). Heterobimetallic N‑Heterocyclic carbene complexes: A synthetic, spectroscopic, and theoretical study. Inorganic Chemistry, 55(14), 6882-6891. doi:10.1021/acs.inorgchem.6b00222

International Standard Serial Number
International Standard Book Number