A Self-Assembled ZnII-NdIII Heterohexanuclear Dimer Based on a Hexadentate N₂O₄-Type Ligand and Terephthalic Acid: Synthesis, Structure, and Fluorescence Properties.

A self-assembled ZnII-NdIII heterohexanuclear coordination compound [Zn₄Nd₂(L)₄(bdc)₂]·2NO₃ based on a hexadentate Salamo-like chelating ligand (H₂L = 1,2-bis(3-methoxysalicylideneaminooxy)ethane]) and H₂bdc (H₂bdc = terephthalic acid) has been synthesized and characterized by elemental analyses, IR and UV/Vis spectra, and X-ray crystallography. Two crystallographically equivalent [Zn₂Nd(L)₂] moieties lie in the inversion center linked by two (bdc)2- ligands leading to a heterohexanuclear dimer in which the carboxylato group bridges the ZnII and NdIII atoms. The heteropolynuclear 3d-4f coordination compound includes four ZnII atoms, two NdIII atoms, four completely deprotonated (L)2- units, two fully deprotonated (bdc)2- units, and two crystalling nitrate ions. All of the ZnII atoms in the ZnII-NdIII coordination compound possess trigonal bipyramidal geometries and the NdIII atoms possess distorted bicapped square antiprism coordination arrangements. In addition, the fluorescence properties of the ligand and the ZnII-NdIII coordination compound were investigated.