Unique complexation by the tridentate ligands, 6-diphenylphosphino-2-pyridonate (pyphos) and 6-diphenylphosphino-2-pyridone (pyphosH), on ruthenium(II): Crystal structures of (pyphosH)RuCl( μ-Cl)Mo 2Cl(pyphos) 3, RuCl 2(CO)(pyphosH) 2, [Ru(pyphos) 3]( μ-Na) 2[Ru(pyphos) 3

Abstract

The diphenylphosphino-2-pyridone ligand (pyphos H) and its anion ligand, pyridonate (pyphos), coordinated to the ruthenium(II) center through two modes: bidentate P-N chelation and monodentate P coordination. Reaction of Mo 2(pyphos) 4 ( 2) with [RuCl 2( η 6- p-cymene)] 2 ( 3) afforded an unexpected trinuclear complex (pyphosH)RuCl( μ-Cl)Mo 2Cl(pyphos) 3 ( 5) accompanied by a monomeric complex ( η 6- pcymene)RuCl 2(pyphosH) ( 4). In complex 5, three pyphos ligands coordinated to a quadruply-bonded Mo 2 core in three different modes: O-N chelation with free phosphine moiety, O-N chelation with a phosphorus atom bound to a ruthenium atom, P-N chelation with an oxygen atom bridged to the ruthenium atom; thereby the pseudo octahedral ruthenium center was surrounded by a phosphorus atom and a nitrogen atom of a pyphosH ligand (P-N chelation), two trans-arranged chloro atoms, the oxygen atom and the phosphorus atom of the two pyphos ligands. Reaction of RuCl x (CO) y with pyphosH gave a mononuclear complex RuCl 2(CO)(pyphosH) 2 ( 6), which has two pyphosH ligands bound to the ruthenium atom through P-N chelation and monodentate P coordination and involves two hydrogen bondings, NH⋯Cl and OH⋯Cl. In addition, treatment of Ru 2(OAc) 4 ( 7) with the sodium salt of the pyphos ligand afforded a heterotetrametallic complex [Ru(pyphos) 3]( μ-Na) 2[Ru(pyphos) 3] ( 8) in which each pseudo octahedral ruthenium(II) center has three pyphos ligands through P-N chelation and two sodium ions were coordinated by four oxygen atoms in distorted tetrahedral geometry.