SYNTHESIS OF MONOMERCURATED N-PROTECTED PYRROLES AND THE USE OF THESECOMPOUNDS 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 mercu rated in the 2-position on treatment with mercuric chloride. The resul ting organomercuric chlorides are symmetrized to the corresponding dio rganomercury 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 determi ned. The acetyl oxygen atom interacts weakly with the mercury centre i n 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)C l(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 treatm ent 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 dime thyIdithiocarbamate gives the neutral monophosphine complex Ru(2-C4H3N SO[O]Ph)(eta(2)-S(2)CNMe(2))(CO)(PPh(3)) (10), the crystal structure o f which has been determined.