Coordination Chemistry of a New Pyrrole-Based PNP Pincer Ligand

We have investigated the coordination chemistry of the new PNP ligand, 2,5-bis((diphenylphosphino)methyl)pyrrole, containing a central pyrrolide unit.  The ligand is synthesized in four steps from pyrrole without the need of any protecting groups and supports several divalent metal complexes in square planar coordination geometries.  These metal complexes have been investigated for small molecule catalysis including CO₂ reduction.  The metal complexes have been characterized by several techniques such as X-ray crystallography, NMR spectroscopy, and cyclic voltammetry.