Synthesis and spectroscopic characterization of (CO)(6)Fe-2{mu-EC(H)=C(2-Th)E'} (E,E' = S, Se, Te; Th = C4H3S) - Structural characterization of (CO)(6)Fe-2{mu-SeC(H)=C(2-Th)Se}

Room temperature stirring of (CO)(6)Fe-2(mu-EE') with 2-thiopheneacetylene (2-ThC=CH) in methanol containing sodium acetate afforded the adducts (CO)(6)Fe-2{mu-EC(H)=C(2-Th)E'} (E = E', EE' = S (1), Se (2) and Te (3); E not equal E', EE' = SeS (4), STe (5), SeTe (6) and TeSe (7)). Compounds 1-7 have been characterized by IR and multinuclear (H-1, C-13, Se-77 and Te-125) NMR spectroscopy. The structure of (CO)(6)Fe-2{mu-SeC(H)=C(2-Th)Se} (2) has been established by single crystal X-ray diffraction methods. It crystallized in the triclinic space group <P(1)over bar> with a = 7.771(2)Angstrom, b = 17.051(4)Angstrom, c = 20.981(5)Angstrom, alpha = 67.00(2)degrees, beta = 80.26(2)degrees, gamma = 88.67(2)degrees, V = 2520 Angstrom(3), Z = 6, D-calc = 2.159 g cm(-3). Full-matrix least squares refinement of 2 converged to R = 0.0635 and R-W = 0.0969. The structure consists of a tetrahedral butterfly core containing the thiopheneacetylene as a bridge between the two wingtip Se atoms, with three terminally bonded carbonyl groups on each Fe atom. (C) 1997 Elsevier Science S.A.