Crystal Structure of a 1,3-Diyne Iron Complex, [(η 5-Cp)₂Fe₂(μ-CO) (CO) {μ, η 1: η 1: η 2-(C=O) C (C₆H₅)=C–C≡CC₆H₅)}]·0.5 (C₂H₄Cl₂), Formed by C–C Bond Coupling with Carbon Monoxide

The compound crystallized in a monoclinic system, and was characterized thus: space group P 2₁/n, a= 7.887(41)Å, b= 21.853(11)Å, c= 14.355(7)Å, β= 100.567(4)°, Z= 4, V= 2432.27(28)Å3. The crystal structure was solved by direct methods and refined by full-matrix least squares on F 2 to final values of R 1 = 0.0539 and wR 2 = 0.1568. 1,3-Diyne of the title compound, undergoing C–C bond coupling with carbon monoxide, cross-links to {(η⁵-Cp)₂Fe₂(μ-CO) (CO)₂}-group to form a 1,2-dimetalla-3-cyclopentene-5-one by a (μ, η 1: η 1: η 2)-bond fashion with atomic distances of Fe1–Fe2 2.553(1)Å, Fe1–C1 2.058(3)Å, Fe2–C2 1.945(3)Å, C1–C2 1.423(4)Å, and C1–C3 1.499(4)Å, respectively.