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

A self-assembled Zn-Nd 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) ligands leading to a heterohexanuclear dimer in which the carboxylato group bridges the Zn and Nd atoms. The heteropolynuclear 3d-4f coordination compound includes four Zn atoms, two Nd atoms, four completely deprotonated (L) units, two fully deprotonated (bdc) units, and two crystalling nitrate ions. All of the Zn atoms in the Zn-Nd coordination compound possess trigonal bipyramidal geometries and the Nd atoms possess distorted bicapped square antiprism coordination arrangements. In addition, the fluorescence properties of the ligand and the Zn-Nd coordination compound were investigated.