Metalation of Cyclic NNN-Pyrrole Pincer Ligands

Abstract

Tridentate nitrogen pincer ligands can play an important role in coordination chemistry with transition metals as they are thermally stable and can be used to synthesize useful transition metal catalysts. These have many organic and inorganic applications such as the study of the stability of these ligand-transition metal complexes as well as their flexibility in accepting different metals. In this module, the NNN-pyrrole ligand, 2,5-Bis(1-pyrrolidinylmethyl)-1H-pyrrole has been synthesized from a reported procedure and is being studied. Metalation is being attempted with group 10 metal precursors, such as PdCl2 and NiCl2, to form the square planar complexes Pd(NNN)Cl and Ni(NNN)Cl, respectively. The success of these reactions will be confirmed via 1H-NMR, though tridentate coordination has not yet been confirmed due to a pyrrole NH peak. Reaction Metalation reactions are now being attempted under changing conditions, with variables such as oxygen content, temperature, and solvent systems in order to better understand the reactivity of these complexes. Upon complete characterization of these complexes via, 1H and 13 NMR spectroscopy and single crystal X-ray diffraction, catalytic reactions such as the amidation of aldehydes with amines will be investigated.