Neutral N-Donor Ligands Derived From Norharman

Metal complexes of nitrogen-donor ligands exhibit some of the most interesting stoichiometric and useful catalytic transformations described in the chemical literature. 1H-pyridin-(2E)-ylidene and related N- donor ligands (Figure 1) have been described recently and their coordination chemistry and catalytic chemistry investigated. [1] A related class of compound can be derived from norharman, a β-carboline, that has wide biological relevance, but no metal coordination chemistry has been reported. Here we describe the preparation of norharman derived ligands and their metal complexes. IR spectroscopic and X-ray structural data (Figure 1) indicate that this class of ligand is a greater electron-donor than the N-heterocyclic carbenes.[2,3] Preliminary catalytic data will also be presented.