Complex hyperfine structures in microwave spectra of covalent iridium compounds

Abstract

Abstract Magnetic resonance spectra are described for two compounds containing covalently bound [IrCl6]2- complexes and one containing [IrBr6]2-, and the results are analyzed using the π-bonding theory developed by Stevens. The spectra show hyperfine structure lines arising from interaction of the magnetic electrons both with the Ir nucleus (I = 3/2) and w ith the Cl (I = 3/2) or Br (I = 3/2) nuclei, and different examples are discussed where the numbers of resolved lines are 4, 8, 13, 16 and 22. It is shown how these structures, the (g-values and the difference between the spectra in [IrCl6]2- and [IrBr6]2- are all consistent with the hypothesis that the magnetic electrons move partly in d-orbits round the central Ir nucleus and partly in pπ-orbits round the outer halogen nuclei of the complex.