Carbenes L derived from imidazole and triazole, as generated from the corresponding azolium precursor salts, smoothly react with simple metal carbonyls such as M(CO)6 (M Cr, Mo, W), Fe(CO)5, and Ni(CO)4 to give the substitution products M(CO)5L, Fe(CO)4L, Ni(CO)3L, and Ni(CO)2L2, respectively, owing to the pronounced C-nucleophilicity of the free carbenes L. Dicarbenes L L form chelate complexes of type M(CO)4(L L) upon treatment with M(CO)6 (M Cr, Mo, W). The new bis(carbene)nickel (0) complex Ni(CO)2L2 and the first member of a metal complex M(CO)4(L L) exhibiting a chelating dicarbene of the triazole series have been characterized by single-crystal X-ray diffraction. It is evident from the present study that heterocyclic mono- and (chelating) dicarbenes of the aza-type are congeners of phosphanes and diphosphanes, resp., with regard to their metal-coordination chemistry. Both in terms of ligand properties and metal complex synthesis, they closely resemble electron-rich phosphanes, e.g. trimethylphosphane.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry
- Materials Chemistry