Hydrocarbon-bridged metal complexes. XLVII. Bis-, tris- and tetrakis(ferrocenyl)-1,3-diketones

Claisen condensation of the enolate from acetylferrocene with diethyloxalat e, 1,8-octanedicarboxylic dimethyl ester, fumaroyl dichloride, the chloride s of terephthalic acid and of 1,3,5-benzenetricarboxylic acid, tetramethyl- 1,2,4,5-benzene tetracarboxylate and with 3,6-di-t-butyl-9,9'-dimethyl-xant hene-1,8-dicarboxylic dimethyl ester gives the corresponding bis-, tris- an d tetrakis (ferrocenyl)-1,3-diketones 2-8. Their oxidation potentials were measured by cyclovoltammetry. Diferrocenoyl methane exists in the crystal a s the keto-enol tautomer.