Complexes of 2,5-Bis(α-pyridyl)pyrrolate with Pd(II) and Pt(II): A Monoanionic Iso-π-Electron Ligand Analog of Terpyridine

Palladium and platinum metal complexes of 2,5-bis­(α-pyridyl)­pyrrolate (PDP) are reported and characterized by spectroscopic methods, single-crystal X-ray diffraction, and elemental analysis. The single-crystal X-ray structures of these complexes exhibit structural features indicative of significant π-backbonding. To illustrate the effect, bond lengths are statistically compared to unmetalated PDP and to a previously reported Zn­(II) complex that exhibits no backbonding. Density functional theory calculations are used to aid understanding of the electronic structural basis of the observed phenomena.