Electronic structure and bonding of the [W 6S 8(CN) 6] 6− cluster anion

Abstract

Dirac–Slater multiple scattering and its non-relativistic limit calculations on the reduced octahedral (20e) [W 6S 8(CN) 6] 6− cluster ion are reported. The non-relativistic limit calculations predict a paramagnetic cluster with a triplet ground state, while the relativistic calculations predict a diamagnetic cluster with a singlet ground state, which is in agreement with the single sharp signal seen in 13C NMR experiments in deoxygenated D 2O at room temperature. We have also calculated the relativistic electronic structure of the oxidized 19e [W 6S 8(CN) 6] 5− cluster ion. The calculated relativistic local density of states at the Fermi level of the [W 6S 8(CN) 6] 6− cluster ion differs from those calculated for the 24e [Re 6S 8(CN) 6] 4− cluster ion. This may explain the different role played by the axial cyanide ligands in their cluster reactivities.