Three 1-D complexes generated from a ferrocenyl carboxylate cadmium(II) precursor through substitution reactions of N-containing ligands: Syntheses, crystal structures and electrochemical properties

Using sodium 2-chloro-4-ferrocenylbenzoate as functional ligand, a mononuclear precursor complex [Cd(η2-OOCClH3C6Fc)2(H2O)3](CH3OH)2} P1 [Fc = (η5-C5H5)Fe(η5-C5H4)] was synthesized, which containing facile leaving groups. The substitution reactions of the precursor ferrocenyl carboxylate complex with basic N-containing ligands gave three 1-D polymers [Cd2(μ2-OOCClH3C6Fc)4(bix)]n1 [bix = 1,4-bis(imidazol-1-ylmethyl)benzene)], {[Cd2(η2-OOCClH3C6Fc)3(η-OOCClH3C6Fc)(mbbbm)2](CH3OH)2}n2 [mbbbm = 1,3-bis(benzimidazole-1-ylmethyl)benzene] and [Cd(η2-OOCClH3C6Fc)2(pbbbm)]n3 [pbbbm = 1,4-bis(benzimidazole-1-ylmethyl)benzene]. Single-crystal X-ray analysis reveals that the 1-D chain structures of polymers 1–3 are bridged by bix, mpbbbm and pbbbm, respectively, and the three polymers present some differences in their structures. Our results also show that the structural integrity of the precursor complex can be maintained in the resultant polymers. Electrochemical studies of the four complexes in THF/CH3OH solution indicate that the half-wave potentials of the ferrocenyl moieties in these complexes are all shifted to positive potential compared with that of free 2-chloro-4-ferrocenylbenzoic acid.