Reactions of Ferrocene and Other Metallocenes

A great deal of chemistry has been carried out on complexes of the ferrocene type. Although most of the discussion here will deal with ferrocene itself, many of the reactions can be carried out with other metallocenes however, the conditions might be different. 

Ferrocene is a very stable compound that melts at 173 °C and can be sublimed without disruption of the metal complex. Many reactions exhibited by ferrocene are essentially those of an aromatic organic compound. For example, sulfonation of ferrocene can be achieved as follows  

Acylation can be carried out by means of a Friedel-Crafts reaction, 

By a sequence of reactions, the two cyclopentadienyl rings can be connected. Using C2H5OCOCH2COCl as the starting acid chloride, it is possible to attach the acyl end to one of the C5H5 rings. Hydrolysis to remove the ethyl group and conversion of that end to an acid chloride followed by another Friedel-Crafts reaction and reduction of the product leads to 

One of the most useful reactions of ferrocene with regard to synthesizing derivatives is metallation. In this reaction, the lithium derivative is first prepared by the reaction of ferrocene with butyllithium, a reaction showing the slight acidity of the hydrogen atoms. 

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