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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.

Imidazolium salts incorporating functional groups represent a class of compounds having great versatility due to their wide range of applications as task specific ionic liquids (ILs)1 or N-heterocyclic carbene precursors (NHCs)2. Recently our research in this field has been dealing with the high-purity synthesis of t-butyloxylcarbonyl (Boc)-protected and deprotected amino-functionalized imidazolium cation [NHR1CH2CH2ImR2]+ ([1]+, R1 = Boc, H; R2 = Me, Bz, Allyl) and related NHC-Ag(I) silver complexes have been obtained by reacting [1]+ with Ag2O.3 Here we report the synthesis of new NHC-Rh(I) (2) complexes that contain an axis of chirality. The enantiomerical inversion has been investigated by variable-temperature NMR spectroscopy, DFT calculation and X-ray diffraction. The catalytic behaviour of 2 in the 1,2 addition reaction of aryl aldehydes with boronic acid will be also presented and discussed.