MERCAPTIDE COMPLEXES OF OSMIUM PORPHYRINS - STRUCTURE OF OS(TTP)(SC6F4H)2

Aryl mercaptans RSH (R = P-tolyl, C6F4H, C6F5, 2,6-Me2C6H3) react with dioxoosmium(VI) porphyrins [porphyrin = meso-tetra-p-tolylporphyrin (TTP), octaethylporphyrin (OEP)] to give diamagnetic osmium(IV) derivatives which contain two mercaptide ligands. When sterically encumbered mercaptans and porphyrins are utilized, an Os(III) mercaptide complex results. Osmium(III) porphyrin mercaptide complexes can also be prepared either by pyridine-promoted reductive elimination of disulfide from Os(TTP)(SR)2 or by treating the metal-metal-bonded dimer [Os2(TTP)2]2+ With mercaptan/pyridine mixtures. The bis(mercaptido)osmium(IV) complex Os(TTP)(SC6F4H)2 has been structurally characterized by X-ray diffraction [monoclinic C2/c, a = 23.750(5) angstrom, b = 16.625(4) angstrom, c = 15.049(3) angstrom, beta = 92.05(2)-degrees, Z = 4] and exhibits short metal-sulfur bond lengths.