Study on the Reaction of Polymeric Zinc Ferrocenyl Carboxylate with Pb(II) or Cd(II)

In this paper, the reaction of polymeric zinc ferrocenyl carboxylate, {[Zn(OOCClH3C6Fc)2(H2O)3](CH3OH)}n (1; FcC6H3ClCOONa = sodium 2-chloro-4-ferrocenylbenzoic), with Pb(NO3)2 or Cd(NO3)2 was investigated. By immersion of selected big single crystals of 1 into aqueous solutions of Pb(NO3)2 and Cd(NO3)2, respectively, two central metal ion exchange induced single-crystal to single-crystal (SCTSC) transformation products, {[Zn0.74Pb0.26(OOCClH3C6Fc)2(H2O)3](H2O)}n (2) and {[Zn0.82Cd0.18(OOCClH3C6Fc)2(H2O)3](H2O)}n (3), could be obtained. In contrast to above-mentioned SCTSC products, 1 can dissolve well in THF solution, and the reaction of the solution containing 1 with Pb(NO3)2 or Cd(NO3)2 results in a 1-D Pb(II) polymer, [Pb(μ2-η2-OOCClH3C6Fc)2(CH3OH)2]n (4), and a mononuclear Cd(II) complex, {[Cd(η2-OOCClH3C6Fc)2(H2O)3](CH3OH)2} (5). Our results indicate that metal ion exchange can be implemented through heterogeneous or homogeneous pathways and suggest an easy means to remove lead and cadmium ions. At the same time, it also set the stage for using analogous metal carboxylates for selective exchange of other cations.