A CHALCOGEN-STABILIZED CLUSTER CONTAINING A S-TRANS-1,3-DIENE LIGAND - SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF ((CO)(6)FE2SE2)(2)(MU-S-TRANS-C4H2)

Reaction of(CO)(6)Fe-2(mu-Se)(2) with HC=CC=CR (R = SiMe(3) or Sn(n)Bu (3)) at room temperature in methanol containing sodium acetate yielded the unexpected product {(CO)(6)Fe2Se2}(2)(mu-s-trans-C4H2) in which a 1,3-butadiene ligand is coordinated to the Fe2Se2 core in a trans con formation as determined by a single-crystal X-ray diffraction studies. The complex was also obtained with a low yield by reaction of(CO)(6)F e-2(mu-Se)(2) with HC=CC=CH under similar conditions.