Diiminepyridine Chemistry


The diiminepyridine ligand, first made world-famous by Brookhart and Gibson, is a curious one. Unlike most traditional ligands, it tends to participate actively in the chemistry of its complexes, be it through strong p-acidity, through uptake of one, two or even three discrete electrons from the metal(s) bound to it, or even through ligand-centered chemical reactivity. It is also unique in giving iron and cobalt complexes active in olefin polymerization. These properties are likely only indirectly related: the actual active species are not low-valent, but without the ligand non-innocence stabilizing low-valent states it might be much harder to arrive at these active species.

The ligand is typically terdentate, but its complexes are highly strained, and there are several examples of easy loss or exchange of the coordinated metal atom.

We are exploring the nature and selectivity of its ligand-centered reactivity, currently primarily in combination with early transition metals. For relevant papers, see numbers 137, 134, 130 and 126 of my publication list.