Engendering reactivity at group 5-heteroatom multiple bonds π-loading

• Published in: Chemical science (Cambridge) 2022-07, Vol.13 (28), p.8224-8242
• Main Authors: Fostvedt, Jade I, Mendoza, Jocelyne, Lopez-Flores, Sacy, Alcantar, Diego, Bergman, Robert G, Arnold, John
• Format: Article
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d2sc02706b

In this Perspective, we discuss the strategy of π-loading, i.e. , coordination of two or more strongly π-donating ligands to a single metal center, as it applies to promoting reactivity at group 5 transition metal-imido groups. When multiple π-donor ligands compete to interact with the same symmetrically-available metal d π orbitals, the energy of the imido-based frontier molecular orbitals increases, leading to amplified imido-based reactivity. This strategy is of particular relevance to group 5 metals, as mono(imido) complexes of these metals tend to be inert at the imido group. Electronic structure studies of group 5 bis(imido) complexes are presented, and examples of catalytically and stoichiometrically active group 5 bis(imido) and chalcogenido-imido complexes are reviewed. These examples are intended to encourage future work exploring π-loaded bis(imido) systems of the group 5 triad. The proof is in the π: when more than one π-donor ligand is bound to a group 5 metal center, imido-based reactivity increases.