Tetranuclear Zn( II) Complex Based on an Asymmetrical Salamo-Type Chelating Ligand: Synthesis, Structural Characterization, and Fluorescence Property.

A new tetranuclear Zn( II) complex, [{Zn(L)(μ- OAc)Zn( H₂O)}₂], based on an asymmetrical salamo-type bisoxime chelating ligand H₃L (6-hydroxy-4′-chloro-2,2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol) was synthesized and characterized by elemental analyses, differential thermal methods, single-crystal X-ray crystallography, and IR, UV-vis, and fluorescence spectra. The Zn( II) complex crystallizes in the triclinic system, space group P-1 with cell parameters a = 9.0742(6) Å, b = 11.8225(5) Å, c = 12.4182(8) Å, Z = 2, V = 1212.56(12) ų, R₁ = 0.0572, and wR₂ = 0.1734. The environment of the tetranuclear Zn(II) complex is penta-coordinated having a slightly distorted trigonal bipyramidal geometry. Moreover, a 1D chain supramolecular structure is formed along the c-axis by the intermolecular C1-H1B⋯O14 hydrogen bonds; in the same manner, C2-H2C⋯Cg2 functions in the formation of supramolecular structures along the a-axis of the 1D chain. A 2D supramolecular structure along the ac plane extends infinitely under the force of intermolecular hydrogen bonds. Differential scanning calorimetry-thermogravimetry thermal analysis provides evidence of the coordination of Zn(II) atoms to the ligand H₃L. The Zn(II) complex shows intense photoluminescence with a maximum emission at ~453 nm upon excitation at 360 nm. [ABSTRACT FROM AUTHOR]