REACTIONS OF 2-FURYL, 2-THIENYL, AND N-METHYL-2-PYRROLYL MERCURIALS WITH [ET3NH][(MU-CO)(MU-RS)FE2(CO)6] COMPLEXES - SYNTHESIS OF FE2(CO)6 COMPLEXES WITH BRIDGING ETA(1)-ETA(2)-FURYL AND THIENYL LIGANDS

Reactions of furyl- and methyl-substituted furyl-, thienyl-, and methyl-substituted thienyl mercurials with [Et3NH][(mu-CO)(mu-RS)Fe2(CO)6] gave products of type A [GRAPHICS] in which the organic ligands are sigma-bonded to iron via an alpha-carbon atom and pi-bonded to the other iron atom via a C=C bond. On the other hand, 1-methyl-2-pyrrolyl mercurials reacted with [Et3NH][(mu-CO)(mu-t-BuS)Fe2(CO)6] to give B. [GRAPHICS] The compound (mu-sigma,pi-C=CHCH=CHO)(mu-PhS)Fe2(CO)6 (10c) crystallizes in the monoclinic space P2(1)/c with a = 7.805 (1) angstrom, b = 17.091 (2) angstrom, c = 13.344 (2) angstrom, beta = 96.90 (1)-degrees, V = 1767.1 angstrom3, and Z = 4. Refinement by full-matrix, least-squares techniques has resulted in residuals of R = 0.027 and R(W) = 0.036, based on 248 parameters refined and 2403 unique observations. The furyl group in the compound bridges the two iron centers, being sigma-bound to one metal while pi-bonded to the other via the adjacent olefin linkage. The oxygen atom and the other olefin linkage in this group point away from the metals and remain uncomplexed.