Organometallic Selenolates. VII. (Benzylselenolato-Se)tricarbonyl(η⁵-cyclopentadienyl)molybdenum(II) and Bis[1,2(η⁵)-cyclopentadienyl]-di-μ-ethylselenolato-di-μ-selenido-dimolybdenum(IV)(Mo—Mo)

Compound (1), [Mo(η⁵-C₅H₅)(C₇H₇Se)(CO)₃], is monomeric in the solid state. The Cp(CO)₃MoSe moiety (where Cp is cyclopentadienyl) displays a `piano-stool' arrangement with an Mo—Se bond length of 2.6294 (4) Å and an essentially ideal tetrahedral bond angle at selenium [109.74 (8)°]. The binuclear compound (2), [Mo₂(η⁵.C₅H₅)₂(C₂H₅Se)₂(Se)₂], consists of linear cp–Mo–Mo–Cp moieties with Mo=Mo double bonds, which are quadruply bridged by two pairs of selenido and ethylselenolato ligands.

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