Synthesis of a Metallaborane Complex Containing Pd(III) and the First Doubly Charge Compensated Ollide Ion. X-ray Crystal Structure of 1,4-Br(2)-1,2,5-(PMe(2)Ph)(3)-closo-1-PdB(11)H(8).

The reaction of [Me(3)NH][nido-B(11)H(14)] with 4 equiv of lithium alkyl in THF at 5 degrees C generated the putative ollide ion, Li(4)[B(11)H(11)], which was not isolated. This was treated in situ with (PMe(2)Ph)(2)PdBr(2) to yield the metallaborane 1,4-Br(2)-1,2,5-(PMe(2)Ph)(3)-closo-1-PdB(11)H(8). This metallaborane contains the first doubly charge compensated ollide ion. It was isolated in low yield from the reaction mixture by chromatography. Characterization of this air-stable palladium ollide complex by magnetic susceptibility, EPR, and CV confirmed that it contains Pd(III) and is paramagnetic. It was also characterized by an X-ray diffraction study of a single crystal. The sample consisted of rust-colored crystals of monoclinic space group P2(1)/c, with a = 9.749(13) Å, b = 16.30(2) Å, c = 21.65(3) Å, beta = 97.21(4) degrees, and Z = 4. The structure was determined by conventional heavy-atom methods and refined to a final value of R = 0.0730 (5172 reflections), R(w) = 0.0620.