Abstract
Using the diphosphinoborane, (PPh(2))(2)BMes (Mes = 2,4,6-Me(3)C(6)H(3)), we report the first examples of η(3)-P,B,P-ligated complexes using Ni(0) and Pt(ii). Reaction of (PPh(2))(2)BMes with Ni(COD)(2) or Pt(COD)Me(2) (COD = 1,5-cyclooctadiene) results in gradual COD displacement to give [η(3)-P,B,P-(PPh(2))(2)BMes]Ni(COD) (3) or [η(3)-P,B,P-(PPh(2))(2)BMes]Pt(CH(3))(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 (11)B NMR spectrum. We also show that treatment of the Pt(IV) halide precursor, [PtMe(3)I](4) with this ligand framework results in migration of X-type ligands (CH(3)(-) and I(-)) to boron and reductive elimination of ethane (C(2)H(6)) to give a distorted square planar zwitterionic Pt(II) complex, Pt[κ(2)-P,P-(PPh(2))(2)B(Mes)(CH(3))][κ(2)-P,P-(PPh(2))(2)B(Mes)(I)] (10). This reactivity suggests the feasibility of (PPh(2))(2)BMes-ligand-induced labilization of M-X ligands.