Metallaborane chemistry. Part V. Reactions of zerovalent nickel and platinum complexes with arachno-5,9-C2B7 carbaboranes; crystal and molecular structure of a carbadibora-allyl nickel complex

Abstract

Reaction of cyclo-octa-1,5-dienebis(triethyiphosphine)nickel with 5,9-Me₂-5,9-C₂B₇H₁₁ leads to evolution of hydrogen and formation of [Ni(C₂B₇H₉Me₂)(PEt₃)₂]. Analogous reactions between C₂B₇H₁₁Me₂ and [Ni(PMe₃)₂(cod)], [Pt(PEt₃)₂(stilbene)],[Pt(PMe₃)₂(stilbene)],or[Pt(PPh₃)₂(stilbene)]give, respectively, [Ni(C₂B₇H₉Me₂)(PMe₃)₂], [Pt(C₂B₇H₉Me₂)(PEt₃)₂], [Pt(C₂B₇H₁₁Me₂)(PMe₃)₂], and [Pt(C₂B₇H₉Me₂)(PPh₃)₂]. The parent arachno-5,9-C₂B₇H₁₃ carbaborane also reacts with [Pt(PEt₃)₂(stilbene)] to give [Pt(C₂B₇H₁₁)(PEt₃)₂]. A single crystal X-ray diffraction study on the nickel compound [6,6-(Et₃P)₂-5.9-Me₂-6,5,9-NiC₂B₇H₉] establishes that the metal atom is joined to a B₂C-system in a 1,2,3-η bonding mode. This crystallizes in the monoclinic space group P2₁/n with Z= 4 in a unit cell of dimensions a= 9.144(2), b= 18.954(5), c= 15.021 (3)Å, β= 90.51 (4)° and the structure refined to R= 0.068 using 3 445 diffracted intensities.