Cation-Exchange Porosity Tuning in a Dynamic 4d-4f-3d Framework for NiII Ion-Selective Luminescent Probe

A heterometallic complex {[Yb-2(L)(6)Cd-2][Cd(H2O)(6)] 6H(2)O}(n) (Yb-Cd) (H2L = oxidiacetic acid) was synthesized under hydrothermal conditions. In Yb-Cd, each L chelates to one Yb3+ center and bonds to two Cd2+ ions in an anti-anti configuration. Yb and Cd atoms are arrayed alternatively and connected by O-C-O bridges to form a cubic octahedral cage as the secondary building unit. Consequently, topological NaCl nets with high symmetry in the cubic space group Fd-3c have been constructed. The [Cd(H2O)(6)](2+) moieties lying in the porosity of anionic metalorganic framework (MOF) act as the thermodynamically stable species, required to balance the two negative charges of [Yb-2(L)(6)Cd-2](2) in Yb-Cd. Interestingly, when Yb-Cd was employed as a precursor and emerged in the aqueous solution of Mn(ClO4)(2) 6H(2)O or Zn(ClO4)(2) 6H(2)O, a reversible single-crystal-to-single-crystal transformation process driven by [Cd(H2O)(6)](2+) cations has been exhibited to generate the heterotrimetallic coordination polymer {[Yb-2(L)(6)Cd-2][Mn(H2O)(6)] 6H(2)O}(n) (Yb-Cd-Mn) or {[Yb-2(L)(6)Cd-2][Zn(H2O)(6)] 6H(2)O}(n) (Yb-Cd-Zn). To the best of out knowledge, Yb-Cd-Mn and Yb-Cd-Zn are the first examples representing 4d-4f-3d polymers based on multicarboxylic acid. Luminescent studies reveal that Yb-Cd-Zn may serve as a good candidate of Ni2+ a luminescent probe. To our knowledge, Yb-Cd-Zn represent the fist example of the 4d-4f-3d framework to exhibit luminescent selectivity for Ni2+.