The surprisingly facile formation of Pd(I)–phosphido complexes from ortho-biphenylphosphines and palladium acetate

The widely-used ortho-biphenylphosphine ligands SPhos and RuPhos not only undergo facile orthometallation with palladium acetate, yielding strained, four-membered dimeric palladacycles but more surprisingly, in the presence of alcoholic solvents, along with the less encumbered analogue MePhos, yield unusual dinuclear Pd(I) complexes, in which the Pd-centers are bridged by both a phosphide ligand and by the arene of a coordinated phosphine donor.