CRYSTAL AND MOLECULAR STRUCTURE OF FERROCENEDICARBOXYLIC ACID

Ferrocenedicarboxylic acid crystallizes as orange-red laths in the monoclinic space group P21/c with a = 8.403 ± 0.010 Å, b = 8.910 ± 0.010 Å, c = 14.192 ± 0.018 Å, β = 90.41 ± 0.08°, and four molecules per unit cell. The structure was refined by least-square methods with anisotropic thermal parameters to a final R of 6.2% for the 1618 observed reflections measured using an automatic diffractometer with molybdenum radiation. Two molecules of ferrocenedicarboxylic acid form hydrogen-bonded dimers. The average C-C distance in the cyclopen tadienide rings of 1.424 ± 0.013 Å is normal. The two cyclopen tadienide rings are twisted by an average of 1° 38′, making the molecule one of the most nearly eclipsed ferrocene derivatives. © 1969, American Chemical Society. All rights reserved.