An Unusual Conversion of Paramagnetic [3-Cl-3,3,8-{Ph2P(CH2)nPPh-μ-(C6H4-ortho)}-1,2-(CH3)2-closo-3,1,2-RuIIIC2B9H8] (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-[Ph2P(CH2)(n)PPh-mu-(C6H4-ortho)]-1,2-Me-2-closo-3,1,2-(RuC2B9H8)-C-III] (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-(eta(2)-O-2)- 3,3,8-[Ph2P(CH2)(n)PPh-mu-(C6H4-ortho)]-1,2-Me-2-closo-3,1,2-(RuC2B9H8)-C-III] (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 [H-1, C-13{1H}, P-31{1H} and B-11{H-1}] along with 2D HSQC correlation spectra for the new dioxygen closo-ruthenacarboranes are discussed.