New Cd(II), Zn(II) helical coordination polymers constructed from hybrid ligands 4-ferrocenylbutyrate and 1,1-(1,4-butanediyl)bis-1H-benzimidazole

Self-assemblies of Cd(II) or Zn(II) salts with hybrid ligands sodium 4-ferrocenylbutyrate and 1,1-(1,4-butanediyl)bis-1H-benzimidazole (bbbm) gave rise to two new coordination polymers {[Cd(η2-OOC(CH2)3Fc)2(bbbm)]·CH3OH}n (1) and {[Zn(OOC(CH2)3Fc)(η2-OOC(CH2)3Fc)(bbbm)]·CH3OH}n (2) (Fc = (η5-C5H5)Fe(η5-C5H4)). Both polymers possess 1D helical chain structures with 21 screw axes along the b-direction although the coordination modes of the 4-ferrocenylbutyrate ligands and the coordination environments of the central metals in the two polymers are different. In addition, the redox properties of polymers 1 and 2 are also investigated and the results show that the formal potentials and the self-diffusion coefficients of the two polymers are close to each other.