Half-Sandwich Arene-Osmium(Ii) Complexes With Phosphinite Ligands

The synthesis of a series of arene-osmium(II) complexes containing phosphinite-type ligands, namely, [OsCl2(eta(6)-p-cymene){R2PO(CH2)(n)Ph}] (R = Ph, n = 1 (4a), 2 (4b), 3 (4c); R = Pr-i, n = 1 (5a), 2 (5b), 3 (5c)) and [OsCl2(eta(6)-benzene){(Pr2PO)-Pr-i(CH2)(2)Ph}] (7), is presented. All these compounds were characterized by elemental analysis and multinuclear NMR spectroscopy (P-31{H-1}, H-1 and C-13{H-1}), and the structure of [OsCl2(eta(6)-p-cymene){Ph2PO(CH2)(3)Ph}] (4c) unequivocally confirmed through a single-crystal X-ray diffraction study. Attempts to generate the tethered species [OsCl2{eta(6):kappa(1)(P)-C6H5(CH2)(n)OPR2}] by intramolecular exchange of the coordinated arene in 4-5a-c or 7, upon thermal or MW heating, failed.