Anilinopyridinate-supported Ru2x+ (x = 5 or 6) paddlewheel complexes with labile axial ligands

Five new metal–metal bonded Ru2 compounds are presented and discussed: Ru2(ap)4ONO2 (2), [Ru2(ap)4NCMe][BF4] (3), Ru2(ap)4FBF3 (4), Ru2(ap)4OTf (5), and [Ru2(ap)4OTf][Ag(OTf)2] (6) (ap = 2-anilinopyridinate). All compounds have a (4,0) arrangement of the ap ligands about the Ru–Ru bond and contain one sterically blocked axial site and one site containing a labile ligand. These compounds display some of the shortest Ru–Ru distances known for this class of compounds. We demonstrate a reversible interconversion between compounds 3 and 4 as the MeCN and BF4− ligands are readily displaced. Despite the presence of labile axial ligands, compounds 2–5 remain high spin with an S = 3/2 ground state as determined by EPR spectroscopy.