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) derivat ives 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 prepar ed 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) comp lex Os(TTP)(SC6F4H)2 has been structurally characterized by X-ray diff raction [monoclinic C2/c, a = 23.750(5) angstrom, b = 16.625(4) angstr om, c = 15.049(3) angstrom, beta = 92.05(2)-degrees, Z = 4] and exhibi ts short metal-sulfur bond lengths.