Contrasting pathways for the reactions of the electron-acceptor ligands tetrachloro-1,2- and -1,4-benzoquinone with the diruthenium diphosphazane-bridged derivatives [Ru2(µ-CO)(CO)4{µ-(RO)2PN(Et)P(OR)2}2](R = Me or Pri)

Abstract

Treatment of [Ru₂(µ-CO)(CO)₄{µ-(RO)₂PN(Et)P(OR)₂}₂](R = Me or Prⁱ) with o-chloranil leads to electron transfer and the fission of one of the diphosphazane ligands to form [Ru₂{µ-(RO)₂PN(Et)C(O)}{(RO)₂POC₆Cl₄O}(CO)₄{µ-(RO)₂PN(Et)P(OR)₂}], characterized by X-ray crystallography for R = Me, and found to contain a chelating (MeO)₂POC₆Cl₄O group and a novel bridging ligand derived by the coupling of a (RO)₂PN(Et) fragment to a co-ordinated carbonyl group; in contrast, reaction with p-chloranil gives the radical anion salt [Ru₂Cl(CO)₅{µ-(RO)₂PN(Et)P(OR)₂}₂][p-OC₆Cl₄O] resulting from the p-chloranil functioning as a chlorinating agent as well as an electron acceptor.