Pentadentate ligands can serve as a well defined and tunable platform for small molecule activation and catalysis. Most examples in the literature, exemplified by the well studied pentapyridyl PY5 ligand introduced by Stack and Feringa, are overall neutral donors, rendering their transition metal complexes dicationic. We have incorporated two borate functions into this framework, rendering the ligand dianionic. This more electron rich donor supports neutral M(II) complexes and makes higher oxidation state derivatives more accessible. This talk will explore the coordination chemistry of these ligands with first row transition metals like Ti, Fe, Co and Ni and discuss our efforts to generate and characterize higher oxidation state complexes that are key intermediates in catalytic processes involving, for example, C-H activation or oxygen reduction.
Warren Piers (University of Calgary)