Synthesis and characterisation of stable carbene–indium(III) halide complexes
Abstract
The reaction of the stable carbene, >:>CN(Pri)C2Me2NPri, with InX3, X = Cl or Br, yielded either the 1∶1 or 1∶2 complexes, [InX3{CN(Pri)C2Me2NPri}] and [InX3{CN(Pri)C2Me2NPri}2], depending upon the stoichiometry employed. X-Ray crystallography showed one of the 1∶1 adducts, X = Br, to be monomeric and tetrahedral. The 2∶1 adducts have a trigonal-bipyramidal geometry with two halides axial and one equatorial. Conductivity and NMR studies suggested all these complexes retain their neutrality in solution. Treatment of InX3 with 1 equivalent of CN(Pri)C2Me2NPri and half an equivalent of water afforded the ionic compounds [HCN(Pri)C2Me2NPri] [InX4{CN(Pri)C2Me2NPri}] which are fluxional in solution at room temperature. The crystal structures of both compounds show the anion to be trigonal bipyramidal with two axial and two equatorial halides.