Reactivity of rhodium-β-diketonato cyclooctadiene derivatives with mono- and di-phosphines. Synthesis, structural and spectroscopic characterization of Rh(I) and Rh(III) species containing unsymmetrical β-diketonate and P-donor ligands

From the reaction of [Rh(Q)(1,5-cod)] (HQ=1-phenyl-3-methyl-4-R-pyrazol-5-one: R=2-thenoyl (HQS) or 2-furanoyl (HQO)) with PPh3, 1,2-bis(diphenylphosphino)ethane (dppe) or 1,3-bis(diphenylphosphino)propane (dppp) in anhydrous solvents under N2 the complexes [Rh(Q)(PPh3)2], [Rh(dppe)2](Q) (Q=QS or QO), and [Rh(dppp)(QO)] were obtained. The reactions of [Rh(QS)(1,5-cod)] with CH3I, I2, HCl and C3H5Br in the presence of PPh3 were also investigated. All compounds obtained were characterized by elemental analyses, FT-IR, ESI-MS spectroscopy, 1H-, 31P- and in selected cases by 13C-NMR spectroscopy. [Rh(QS)(PPh3)2], [Rh(dppe)2](QS), [Rh(QO)(dppp)] and [Rh(QS)Cl2(PPh3)2], were also characterized in the solid state by single crystal X-ray diffraction. In the air oxidation of [Rh(Q)(PR3)2] and [Rh(QO)(dppp)] occurred, species containing a η2-peroxo group being always identified.