An effective method for the synthesis of monoferrocenylbenzene derivatives

Three new ferrocenylbenzene derivatives, 1-ferrocenyl-2,3,4,5-tetramethylbenzene (1), 1-ferrocenyl-2,4-diphenylbenzene (2), and 1-ferrocenyl-2,4-ditrimethylsilylbenzene (3), were synthesized by cycloaddition of ferrocenylacetylene cobalt cluster with different alkynes and characterized by elemental analysis, FT-IR, NMR, and MS. The molecular structures of 2 and 3 were identified by single-crystal X-ray diffraction. The oxidation potentials of ferrocenyl unit in these compounds were investigated by cyclic voltammetry and theoretical calculations. The results indicated that the electron-donating or electron-withdrawing effect of substituents on the central phenyl was the key factor that influenced the oxidation potential of the ferrocenyl unit.