The chemistry of rhenium alkyls. Part IV. Electron spin resonance spectra of hexamethylrhenium(VI) and the octamethylrhenate(VI) ion

Abstract

Well-resolved e.s.r. spectra of hexamethylrhenium(VI) and the octamethylrhenate(VI) ion are analysed. For ReMe₆ the resulting Hamiltonian parameters are consistent with distorted octahedral symmetry. For the octamethylrhenate(VI) ion, [ReMe₈]^2–, a square antiprism structure best fits the parameters. The g values in both cases are inflated, probably through participation of excited charge-transfer states from high-lying bonding orbitals and good agreement with existing theory is not obtained. The nuclear-spin electron-orbit interaction, which is commonly neglected, is found to give an appreciable contribution to A_iso in these compounds.