An Unusual Conversion of Paramagnetic [3-Cl-3,3,8-{Ph(2)P(CH(2))(n)PPh-µ-([Image: see text] H(8)] (n = 3 and 4) to Form the First 18-Electron P-Phenylene ortho-Cycloboronated closo-Ruthenacarboranes with a Dioxygen Ligand

Treatment of [3-Cl-3,3,8-[Ph(2)P(CH(2))(n)PPh-µ-([Image: see text] H(8)] (1, n = 3; 2, n = 4) with an excess of KOH in a 1:1 benzene/methanol mixture at room temperature in air affords new dioxygen closo-ruthenacarborane complexes [3-(η(2)-O(2))-3,3,8-[Ph(2)P(CH(2))(n)PPh-µ-([Image: see text] H(8)] (3, n = 3) and (4, n = 4) in 42.5% and 45.8% yield respectively. The structures of dioxygen complexes 3 and 4 were established by single-crystal X-ray diffraction. The IR and multinuclear NMR data [(1)H, (13)C{(1)H}, (31)P{(1)H} and (11)B{(1)H}] along with 2D HSQC correlation spectra for the new dioxygen closo-ruthenacarboranes are discussed.