W₆S₈ inorganic clusters with organic TTF derivative ligands: In pursuit of multidimensional conductive networks

A series of new molecular cluster complexes with TTF derivative ligands attached to an inorganic W₆S₈ core were prepared, namely W₆S₈(PEt_3-n TTF_n,)₆ (n = 1, 2). By incorporating two useful structural motifs (the well-known π-π stacking geometry of TTF molecules and the high symmetry of octahedral clusters) into one network structure, we constructed multidimensional networks. Single-crystal X-ray diffraction studies revealed intercluster TTF π-contacts in one and two dimensions, for W₆S₈(PEt ₂TTF)₆ and W₆S₈(PEtTTF ₂)₆, respectively. The redox properties of W ₆S₈(PEt₂TTF)₆ were studied by cyclic voltammetry. Mid- and far-IR and XPS (X-ray photoelectron spectroscopy) characterizations were performed on both the W₆S₈(PEt ₂TTF)₆ cluster and its oxidized product, which helped to elucidate the identity of the poorly crystalline oxidized product. Four-point contact electrical conductivity measurements were performed on a pressed pellet of the oxidized powder product W₆S₈(PEt ₂TTF)6·xPF₆ (x ≈ 5) with σ_RT ≈ 1 × 10^-4 S cm^-1, whereas the neutral cluster complex is insulating at room temperature.