The crystal structure of α-keto-1,1'-trimethyleneferrocene

Abstract

The crystal structure of α-keto-1,1'-trimethyleneferrocene has been determined by three-dimensional X-ray diffraction analysis. This compound, Ca_3H_(12)OFe, crystallizes in the centrosymmetric monoclinic space group P2_1/a. The unit cell contains four molecules and has the dimensions a=22.981 ± 0.002, b=7-381 ± 0.001, c=5.833 ± 0.001 A; β = 93.38 ± 0.02°. A trial structure was obtained from the locations of the iron-iron vectors in the (001) Patterson projection and was refined in both two and three dimensions by the method of least squares. The final reliability factor, R, was 0.067. The dihedral angle between the best planes through the two nearly planar cyclopentadienyl rings is about 8.8 °. The average ring carbon-carbon bond distance is 1.424 ± 0.010 A and the average iron-carbon bond distance is 2.039 ± 0.006 A. The principal thermal motion is a vibration of the entire molecule in a direction roughly perpendicular to the ab plane.