Synthesis and Characterization of Tungsten Alkylidene and Alkylidyne Complexes Supported by a New Pyrrolide-Centered Trianionic ONO3- Pincer-Type Ligand

Synthetic protocols for a pyrrolide-centered ONO3- trianionic pincer-type ligand are presented. Treating ((BuO)-Bu-t)(3)W equivalent to(CBu)-Bu-t with the proligand [pyr-ONO]H-3 (2) results in the formation of the trianionic pincer alkylidene complex [pyr-ONO]W=(CHBu)-Bu-t((OBu)-Bu-t) (3). Addition of a mild base to complex 3 provides the trianionic pincer alkylidyne complex {MePPh3}{[pyr-ONO]W equivalent to(CBu)-Bu-t((OBu)-Bu-t)} (4). All new compounds were characterized by NMR spectroscopy, combustion analysis, and, in the case of complex 4, single-crystal X-ray crystallography. D FT calculations performed on 4 provide insight into its electronic structure and indicate that the HOMO is ligand-based and localized on the pyrrolide pi orbitals.