Synthesis and characterization of nickel(II) and palladium(II) pyrrolyl complexes and their polymerization to electroactive materials

Four new transition metal-pyrrolyl complexes, bis(pyridyl)bis(pyrrolyl)palladium(II), (2,2'-bipyridyl)bis(pyrrolyl)palladium(II), (6-phenyl-2,2'-bipyridine)(pyrrolyl)pall and bis(trimethylphosphino)(pyrrolyl)nickel(II) chloride, have been prepared and characterized. DFT calculations indicate that radical cations of the palladium compounds and their dimers have spin densities primarily on the pyrrolyl ligand, while the spin density of the nickel species radical is diffuse. Each complex was found to undergo oxidative polymerization to semiconducting polymers with good thermal properties. Polymers prepared with dodecylbenzenesulfonate as the counterion were soluble and could be cast into smooth, films with good physical properties.