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

Abstract

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)·2(CH3OH)·(CH2Cl2) and {[CdDyL(IN)(OAc)(NO3)(CH3OH)]·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 DyIII 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 DyIII 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 ZnII ions and CdII ions.