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

Using the diphosphinoborane, (PPh2)(2)BMes (Mes = 2,4,6-Me3C6H3), we report the first examples of (3)-P,B,P-ligated complexes using Ni(0) and Pt(ii). Reaction of (PPh2)(2)BMes with Ni(COD)(2) or Pt(COD)Me-2 (COD = 1,5-cyclooctadiene) results in gradual COD displacement to give [(3)-P,B,P-(PPh2)(2)BMes]Ni(COD) (3) or [(3)-P,B,P-(PPh2)(2)BMes]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 B-11 NMR spectrum. We also show that treatment of the Pt-IV 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 Pt-II complex, Pt[(2)-P,P-(PPh2)(2)B(Mes)(CH3)][(2)-P,P-(PPh2)(2)B(Mes)(I)] (10). This reactivity suggests the feasibility of (PPh2)(2)BMes-ligand-induced labilization of M-X ligands.