M. Almond, E. Page, D. A. Rice
Mar 24, 1994
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0
Influential Citations
10
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract The molecular structure of cyclopentadienyl manganese tricarbonl, C5H5Mn(CO)3, has been studied by gas-phase electron diffraction at 70°C. Two models fit the experimental data equally well: model A, which allows for free rotation of the Mn(CO)3 moiety (that has C3v symmetry) about the MnX axis (X is the centre of the cyclopentadienyl ring), and model B, which has a staggered arrangement of the carbonyl groups with respect to the cyclopentadienyl ring. The final geometrical parameters for model A are: rg(MnC(ring)) = 2.149(3) A, rg(MnCO) 1.808(3) A, rg(CC) = 1.424(2) A, rg(CO) = 1.148(3) A, ∠(OCMnCO) = 92.0(0.5)° with an R-fa of 5.55%. The final geometrical parameters for model B are: rg(MnC(ring)) = 2.149(3) A, rg(MnCO) = 1.808(3) A, rg(CC) = 1.424(2) A, rg(CO) = 1.148(2) A, ∠(OC-Mn-CO) = 91.9(0.4)°, R = 5.55% from which it can be seen that the geometrical parameters show no significant difference from those obtained with model A. No definitive evidence was obtained for the HC bonds being bent out of the plane of the Cp ring. When the HCX angle was allowed to refine, a value of 1.7(3.4)° was obtained. A positive value indicates that the hydrogen atoms are on the same side of the ring as the manganese atom.