Asymmetrically Difunctionalized 1,1 '-Ferrocenyl Metalloligands and Their Transition Metal Complexes

The synthesis and full characterization of novel 1,1 '-difunctionalized ferrocene metalloligands is described. While one cyclopentadienyl ring has been functionalized with 2,2 '-bipyridine for secondary coordination, the second Cp ring has been decorated with different aryl moieties containing electron withdrawing groups such as 4-(CF3)C6H4 (2A) 3,5-(CF3)(2)C6H3 (2B) or 4-(NO2)C6H4 (2C). The newly developed metalloligands were reacted with [Pd(cod)Cl-2] (3A-C), CuCl2 (4A-C) and trans-[(PPh3)(2)Ni(Mes)Br] (5A,B) to obtain the corresponding square-planar and dimeric square-pyramidal complexes. The electrochemical behaviour of the ligands and complexes was investigated with the aid of cyclic voltammetry and compared with the corresponding monofunctionalized derivatives. The influence of the implemented functional groups on the nickel complexes was then confirmed for the reductive elimination reaction of an aryl ether induced by oxidation of the corresponding methoxides (6A,B,D). The experimental findings are supported by quantum chemical calculations.