Some ring replacement and nucleophilic substitution reactions of η6-subsituted arene-η5-cylopentadienyliron hexafluorophosphates

A number of nitroarene and aminoarene complexes, including the PF6− salts of NO2C6H5FeCpp+, 0-, m- or p-CH3(NO2)C6H4FeCp+, NH2C6H5FeCpp+ and 0-, m-, orp-CH3(NH2)C6H4FeCpp+, when heated with an excess of P(OC2H5)3 all gave rise to the ring replacement product, CpFe(P(OC2H5)3)3+ PF6− (I). Similarly, the thermal reaction of NO2C6H5Fe(CH3)Cp+ PF6− or NH2C6H5Fe(CH3)Cp+ PF6− with P(OC2H5)3 gave CH3CpFe(P(OC2H5)3)3+ PF6− (VII). With m-CH3(Cl)C6H4-FeCp+ PF6− (XIV), heating with P(OC2H5)3 also gave rise to I, while the same treatment with P(OC2H5)3 at room temperature in CH2Cl2 showed no nucleophilic substitution of the chlorine atom of XIV by P(OC2H5)3. On the other hand, the chlorine atom of a number of chloroarene complexes could be readily displaced at room temperature with various amines acting as nucleophiles. Such nucleophilic substitutions were carried out on ClC6H5FeCp+ PF6− and 0-, m- or p-CH3(CI)C6H4FeCp+ PF6− with methylamine, ethylenediamine, cyclohexylamine, benzylamine and pyrrolidine to give rise to 20N-substituted aminoarene complexes.