N. Kuhn et al., HETEROCYCLES AS LIGANDS .20. SPECTROSCOPI C AND STRUCTURAL CHARACTERIZATION OF PENTACARBONYLMETAL COMPLEXES OF IMIDAZOL-2-YLIDENES, Journal of organometallic chemistry, 470(1-2), 1994, pp. 30000008-30000011
The imidazol-2-ylidene complexes I-III are obtained from M(CO)6 (M = C
r, Mo, W) and the corresponding imidazol-2-ylidenes in good yields. C-
13-NMR data and the X-ray structure of II confirm the carbenes to be s
trong donor ligands, no evidence for significant pi-interaction betwee
n the carbene carbon atom and the metal centre being detected.