SYNTHESIS OF MONOMERCURATED N-PROTECTED PYRROLES AND THE USE OF THESE COMPOUNDS AS PYRROLYL GROUP-TRANSFER REAGENTS TO RUTHENIUM AND OSMIUM - CRYSTAL-STRUCTURES OF (2-C4H3NC[O]CH3)HGCL, (2-C4H3NC[O]CH3)(2)HG AND RU(2-C4H(3)NSO[O]PH)(S(2)CNME(2))(CO)(PPH(3))

N-Acetylpyrrole and N-phenylsulfonylpyrrole are each selectively mercurated in the 2-position on treatment with mercuric chloride. The resulting organomercuric chlorides are symmetrized to the corresponding diorganomercury derivatives (2-C4H3NC[O]CH3)HgCl (2) and (2-C4H3NSO[O]Ph)(2)Hg (4) by the action of sodium iodide. The crystal structures of (2-C4H3NC[O]CH3)HgCl (1) and (2-C4H3NC[O]CH3)(2)Hg (2) have been determined. The acetyl oxygen atom interacts weakly with the mercury centre in both cases, but more strongly in 1 than 2. Treatment of the hydride complexes MHCl(CO)(PPh(3))(3) (M=Ru, Os) with the diorganomercurial 2 or 4 affords in good yield the 2-pyrrolyl complexes M(2-C4H3NC[O]CH3)Cl(CO)(PPh(3))(2) or M(2-C4H3NSO[O]Ph)Cl(CO)(PPh(3))(2), respectively. In each case the pyrrolyl group is coordinated in a bidentate fashion through C-2 and an oxygen atom of the N-substituent. The chloride ion in [Ru(2-C4H3NSO[O]Ph)Cl(CO)(PPh(3))(2) (7) is labile, and upon treatment with AgSbF6 and CO, the cationic complex Ru(2-C4H3NSO[O]Ph)(CO)(2)(PPh(3))(2)]SbF6 is formed. Treatment of 7 with AgSbF6 and sodium dimethyIdithiocarbamate gives the neutral monophosphine complex Ru(2-C4H3NSO[O]Ph)(eta(2)-S(2)CNMe(2))(CO)(PPh(3)) (10), the crystal structure of which has been determined.