Bimetallic d10‐Metal Complexes of a Bipyridine Substituted N‐Heterocyclic Carbene

• Published in: Chemistry : a European journal 2018-04, Vol.24 (23), p.6094-6104
• Main Authors: Kaub, Christoph, Lebedkin, Sergei, Li, Alina, Kruppa, Sebastian V., Strebert, Patrick H., Kappes, Manfred M., Riehn, Christoph, Roesky, Peter W.
• Format: Article
• Language: English
• Subjects: Bimetals; Cadmium; Cations; Chains; Chemistry; coinage metals; Coordination compounds; Copper; Gold; Heavy metals; Mercury (metal); Metal complexes; Metal ions; metallophilicity; N-heterocyclic carbenes; Photoluminescence; Photons; Properties (attributes); Reagents; Silver; Species; Zinc
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201705757

The hybrid ligand 3‐(2,2′‐bipyridine‐6‐ylmethyl)‐1‐mesityl‐1H‐imidazolylidene (NHCBipy) featuring both carbene and N‐donor sites, was selectively complexed with various d10 metal cations in order to examine its coordination behavior with regard to homo and heterometallic structures. Respective silver complexes can be obtained by the silver oxide route and are suitable transmetallation reagents for the synthesis of gold(I) compounds. Starting from the mononuclear complexes [(NHCBipy)AuCl], [(NHCBipy)Au(C6F5)] and [(NHCBipy)2Au][ClO4], open‐chain as well as cyclic heterobimetallic complexes containing Cu+, Ag+, Zn2+, Cd2+, and Hg2+ were synthesized. Furthermore, the homobimetallic species [(NHCBipy)2M2][ClO4]2 (M=Cu, Ag) were obtained. All bimetallic compounds were fully characterized including single‐crystal X‐ray analysis. Their photoluminescence (PL) properties were investigated in the solid state at temperatures between 15 and 295 K and compared with those of the mononuclear species. There is a clear difference in PL properties between the open chain and the cyclic heterobimetallic complexes. The latter species show different PL properties, depending on the metals involved. In addition, collision‐induced dissociation (CID) experiments were performed on electrosprayed cations of the cyclic heterobimetallic compounds, to compare the metal binding at the carbene and N‐donor sites. Doubling up: The coordination behaviour of 3‐(2,2′‐bipyridine‐6‐ylmethyl)‐1‐mesityl‐1H‐imidazolylidene (NHCBipy) in bimetallic d10 metal complexes was examined and their photophysical properties were investigated. While open‐chain bimetallic complexes show similar luminescence as compared to their mononuclear precursor, the properties of the cyclic molecules are strongly affected by the second metal.