Cyclobutadienes ferrocenyl groups

The cyclobutadiene ring is distorted square planar, in that one carbon is out of the plane formed by the remaining three carbon atoms by 0.035 A. The cyclopenta-dienyl rings of the two ferrocenyl groups are eclipsed. 

There are no significant differences among the redox potentials of the complexes. It has only to be noted that the appearance of discrete oxidation steps for the ferrocenyl groups indicates that the cyclobutadiene ring allows electronic interaction between its substituents. 

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