y Two heteronuclear ZnII/CdII-DyIII complexes based on open-chain ether schiff base ligand: Synthesis, structures, fluorescence and antioxidation activity

Two open-chain ether Schiff base d-f heteronuclear complexes with bis(5-bromine-3-methoxysalicylidene)-3-oxapentane-1,5-diamine (H2L) and isonicotinate (IN), with composition [Zn2DyL2(OAc)(IN)] (NO3)center dot 2(CH3OH)center dot(CH2Cl2) and {[CdDyL(IN)(OAc)(NO3)(CH3OH)]center dot 3(CH2Cl2)}(n), have been synthesized by interfacial diffusion methods and further performed structural characterization. The structure analysis revealed that Zn-Dy complex is heterotrinuclear complex and Dy-III ion acts as a joint bridging of two ZnL coordination units, whereas Cd-Dy complex is infinite 1D zigzag coordination polymer formed by CdDyL secondary units through bridging of isonicotinate. Fluorescence properties of 1-2 in the solid state and DMF solution at room temperature were also studied. It has been found that the emission spectra of complexes 1-2 do not exhibit corresponding Dy-III ion characteristic emission peaks and the emission bands of complexes 1-2 are different due to the introduction of different transition metal ions. Antioxidation properties of the ligand and 1-2 were also studied, showing that the order of antioxidant activity is complex 2 > complex 1 > H2L. Thus, the structures and properties when constructing d-f heteronuclear complexes could be adjusted by selecting different transition metal ions such as Zn-II ions and Cd-II ions.