An experimental and computational comparison of phosphorus- and selenium-based ligands for catalysis

To compare and contrast the bonding and reactivity of organoselenium ligands with organophosphines in coordination complexes, a new palladium(II) complex of the Se,N-chelating ligand o-(NH2)(X)C6H4 (X = SePh, 2) was prepared. Its characterization by NMR spectroscopy, single-crystal X-ray diffraction, and density functional theory calculations is contrasted with the PdII complex of the related P,N- chelating ligand (X = PPh2, 1). These techniques indicate that the phenylseleno moiety is a weaker σ donor to the PdCl2 fragment than the diphenylphosphino group. Both complexes were suitable to catalyze the Suzuki–Miyaura coupling of p-tolylboronic acid and 4-bromobenzaldehyde.