Metallacarboranes derived from the [C2B10H12]2– anion. The preparation, molecular structure, and properties of [4-(dppe)-4-Pd-1,6-C2B10H12], [4,4,4-H(PPh3)2-2-OMe-4-Ir-1,6-C2B10H11], and [3-(dppe)-3-Pt-1,2-C2B9H11]

Abstract

The action of Na₂[C₂B₁₀H₁₂] on [PdCl₂(dppe)](dppe = Ph₂PCH₂CH₂PPh₂) yields the 13-vertex yellow closo species [(dppe)PdC₂B₁₀H₁₂](1), and the reaction of [NMe₄][C₂B₁₀H₁₃] with [IrCl(PPh₃)₃] in light petroleum–methanol gives a related 13-vertex cage of yellow [(PPh₃)₂HlrC₂B₁₀H₁₁(OMe)](2), whose formation involves attack by a solvent molecule. The structure of both products have been established by X-ray diffraction [R= 0.039 and 0.074 for 4 786 and 4 130 diffractometer-measured observed reflections, for (1) and (2) respectively]. Both show the characteristic 1:5:6:1 structure for 13-vertex polyhedra, distorted by carbon substitution. The reaction of Tl(O₂CMe) with Na₂[C₂B₁₀H₁₂] in ethanol leads to degradation of the C₂B₁₀ cage, and yields an orange solid formulated as Tl₃(C₂B₉H₁₂)O. Treatment of this solid with [PtCl₂(dppe)] gives the pale orange [(dppe)PtC₂B₉H₁₁](3); it has an icosahedral structure [R= 0.068 for 3 530 observed reflections], distorted mainly by the lengthening of the Pt–C bonds in comparison to the Pt–B bonds.