[W6S8] octahedral tungsten clusters functionalized with thiophene derivatives:: toward polymerizable building blocks

The functionalization of octahedral [W6S8] Clusters with a family of phosphino-thiophene ligands has been investigated with the goal of synthesizing extended networks of [W6S8] units covalently linked to one another through thiophene-conjugated bridges. In addition to new phosphino-thiophene ligands, eight clusters were synthesized and characterized by H-1 and P-31 NMR spectroscopies, elemental analysis, and UV-vis absorption. These clusters are formulated [W6S8(T-PPh2)(6)] (1a), [W6S8(T-PEt2)(6)] (1b), [W6S8(2T-PPh2)(6)] (2a), [W6S8(2T-PEt2)(6)] (2b), [W6S8(3T-PPh2)(6)] (3a), [W(6)s(8)(3T-PEt2)(6)] (3b), [W6S8((2T)(3)P)(6)] (4), and [W6S8(2EDOT-PEt2)(6)] (5) (T = thiophene and EDOT = 3,4-ethylenedioxythiophene). The molecular structure of six of them has been obtained by single-crystal X-ray diffraction analysis. All of them crystallize in the P (1) over bar triclinic space group except 3b, which has the P2(1)/c monoclinic symmetry. The redox behavior of both the ligands and the corresponding functionalized clusters has been investigated by cyclic voltammetry. An attempt to electropolymerize these species is also reported.