Ferrocene(redirected from Ferrocenium)
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(also dicyclopentadienyliron), (C5H5)2Fe, an orange crystalline solid having a melting point of 173°–174°C that is readily soluble in organic solvents. First synthesized in 1951, ferrocene is a member of a large class of organometallic compounds known as metallocenes. The ferrocene molecule has the sandwich structure that is characteristic of the class:
Ferrocene undergoes substitution reactions to the cyclopentadienyl rings; in this sense, the compound is similar to benzene and other aromatic compounds. For example, it is alkylated and acylated in the Friedel-Crafts reaction, and it also undergoes mercuration and sulfonation. The compound is stable at temperatures up to 400°C when heated in the air; it is also stable in the presence of acids and alkalies. Ferrocene is obtained by heating cyclopentadiene (C5H6) with metallic iron and by the reaction of cyclopentadienylmagnesium bromide (C5H5MgBr) with ferrous chloride.