Bismuth-rich bimetallic clusters (CuBi8)(3+) and [MBi10](4+) (M = Pd, Pt) from ionothermal synthesis

The reaction of Bi, BiBr3, and CuBr in the Lewis-acidic ionic liquid [BMIm]Br center dot 4AlBr(3) (BMIm = 1-n-butyl-3-limidazolium) at 180 degrees C yielded air-sensitive, shiny black crystals of (CuBi8)[AlBr4](2)[Al2Br7]. Crystals of [MBi10][AlCl4](4) (M = Pd, Pt) were obtained by reacting Bi, BiCl3, and MCl2 under similar conditions. The structures have been determined by X-ray diffraction on single-crystals and were found to be very similar to that of the known analogues with other halogens, although not isostructural. In crystals of the complex salts, polyhedral bimetallic clusters (CuBi8)(3+) or [MBi10](4+) are embedded in matrices of halogenidoaluminate anions. The heteroatomic nido-cluster (CuBi8)(3+) consists of a (Bi-8)(2+) square antiprism eta(4)-coordinating a copper(I) cation. In the cluster cation [MBi10](4+), the metal atoms M center a pentagonal antiprism of bismuth atoms.