Expanding the allyl analogy: accessing η3-P,B,P diphosphinoborane complexes of group 10.

Using the diphosphinoborane, (PPh2)2BMes (Mes = 2,4,6-Me3C6H3), we report the first examples of η3-P,B,P-ligated complexes using Ni(0) and Pt(ii). Reaction of (PPh2)2BMes with Ni(COD)2 or Pt(COD)Me2 (COD = 1,5-cyclooctadiene) results in gradual COD displacement to give [η3-P,B,P-(PPh2)2BMes]Ni(COD) (3) or [η3-P,B,P-(PPh2)2BMes]Pt(CH3)2 (6). Complex 3 serves as a versatile Ni-containing synthon for the preparation of square planar or tetrahedral Ni(0) complexes. Notably, the M-B interaction in these systems is non-negligible - with coordination resulting in an upfield shift of ca. 80 ppm in the 11B NMR spectrum. We also show that treatment of the PtIV halide precursor, [PtMe3I]4 with this ligand framework results in migration of X-type ligands (CH3- and I-) to boron and reductive elimination of ethane (C2H6) to give a distorted square planar zwitterionic PtII complex, Pt[κ2-P,P-(PPh2)2B(Mes)(CH3)][κ2-P,P-(PPh2)2B(Mes)(I)] (10). This reactivity suggests the feasibility of (PPh2)2BMes-ligand-induced labilization of M-X ligands.