Formation of hexaosmium raft clusters from [Os-6(CO)(16)(MeCN)(2)]: synthesis, structural characterisation and reactivities of [Os-6(CO)(16)(mu(3)-eta(2)-C5H4NS)(2)] and [Os-6(CO)(17)(mu-H)(mu(4)-eta(2)-C5H4NS)]

Reaction of [Os-6(CO)(16)(MeCN)(2)] with 1 equivalent of 2-Aldrithol in CH2 Cl2 under ambient conditions afforded two new raft clusters [Os-6(CO)(16)(m u(3)-eta(2)-C5H4NS)(2)] 1 and [Os-6(CO)(17)(mu-H)(mu(4)-eta(2)-C5H4NS)] 2 i n moderate and fair yields, respectively. Cyclic voltammograms of compound 1 exhibited two metal-based, one-electron reduction couples at E-1/2=0.36 a nd -0.20 V together with an irreversible ligand-based anodic wave at ca. E- pa=+0.31 V vs. Ag-AgNO3. Protonation of 1 with CF3CO2H produced an unstable species [Os-6(CO)(16)(mu(3)-eta(2)-C5H5NSH)(mu(3)-eta(2)-C5H5NS)][CO2CF3] 3, which upon standing in CH2Cl2 quickly decomposed. All compounds have bee n fully characterised by spectroscopic methods, while the molecular structu res of 1 and 2 were established by crystallographic techniques. Both 1 and 2 contain 'ladder'-type and edge-fused raft cluster cores, with the sulfur atom in 2 being drawn intimately into the cluster envelope. These clusters serve as good models for substrates adsorbed onto metal surfaces.