23-Electron Re6 metal clusters: syntheses and crystal structures of (Ph4P)3[Re6S8(CN)6], (Ph4P)2(H)[Re6Se8(CN)6]·8H2O, and (Et4N)2(H)[Re6Te8(CN)6]·2H2O

The cluster anions [Re6X8(CN)6]34– (X = S, Se, or Te) containing 23 cluster valence electrons in the Re6 octahedron were synthesized and isolated as salts with organic cations. The crystal structures of the (Ph4P)3[Re6S8(CN)6], (Ph4P)2(H)[Re6Se8(CN)6]·8H2O, and (Et4N)2(H)[Re6Te8(CN)6]·2H2O clusters were solved by X-ray diffraction analysis. Removal of one electron has virtually no effect on the geometry and interatomic distances in the cluster anion but leads to a substantial change in the electronic spectrum and to an increase in stretching vibration frequencies νCN compared to those of the [Re6X8(CN)6]4– anions.