UC San Diego

The title iron(II) complex, [Fe(C16H12NO2)2], crystallizes in the ortho-rhom-bic space group Pbca with the Fe(2+) cation positioned on an inversion center. The cyclo-penta-dienyl (Cp) rings adopt an anti conformation in contrast with other substituted ferrocenes in which the Cp rings appear in a nearly eclipsed conformation. The Cp and the aromatic rings are positioned out of the plane, with a twist angle of 70.20 (12)°, and the C(Cp)-C(CO) bond length is shorter than a typical C-C single bond, which suggests a partial double-bond character and delocalization with the Cp π system. The structure of the complex is compared to other functionalized ferrocenes synthesized in our laboratory.