Phosphino-arene ruthenium complexes containing the phosphorus acid anion {P(=O)(OR)(2)} as P-donor

The cationic complex [Ru(OTf)(P(OH)Ph-2){Ph2P-(eta (6)-arene)}]OTf,2(2a=6'-diphenylphosphino-1'-naphthyl-eta (6)((1-6))-naphthalene, 2b = 6,6'-dimethoxy-2'-diphenylphosphino-eta (6)((1-6))-biphenyl), is shown to react with water/tert-butyl alcohol/THF mixtures to afford [Ru(P(=O)(OH)(2){Ph2P-(eta (6)-arene)}](2)(OTf)(2), 4. The solid-state structure of a derivative, [Ru{P(=O)(OH)(OMe)}{Ph2P-(naphthyl-eta (6)-naphthalene}](2)(OTf)(2), 6, is reported and found to possess extremely asymmetric eta (6)-arene bonding. Complexes 4 and 6, plus a mononuclear dimethoxy analogue, [Ru(P(=O)-(OMe)(2)(Ph2P-(naphthyl-eta (6)-naphthalene)](OTf), 8, represent the first examples of Ru-compounds that contain the phosphorus acid anion P(=O)(OR) 2 (R = H and/or Me) as an anionic P-donor ligand. PGSE diffusion measurements are shown to be helpful in distinguishing between dinuclear oxygen bridging species and their mononuclear analogues.