Auxiliary ligands induced two new Zn(II) compounds with the structural variations from 2D layer to 3D framework: Syntheses, structures and photoluminescent properties

Abstract

Two new Zn(II) compounds, [Zn2(L)(2,2′-bipy)2(H2O)2]n (1) and [Zn2(L)(phen)2(H2O)]n (2) (H4L = 3-(2′,4′-dicarboxylphenoxy)phthalic acid, 2,2′-bipy = 2,2-bipyridine, phen = 1,10-phenanthroline), were successfully obtained via the solvothermal reactions of semi-rigid V-shaped tetracarboxylic acid together with 2,2′-bipy or phen as the auxiliary ligand. These two compounds were structurally characterized by single crystal X-ray diffraction analyses, elemental analyses, powder X-ray diffraction and thermogravimetric analyses. Compound 1 features a 2D layered structure and these 2D layer motifs further stacked into a 3D supramolecular framework via relatively weak Van der Waals interactions. Compound 2 features a 3D framework with 4-connected mog topology. The structural difference between the two compounds indicates that the N-containing auxiliary ligands play an important role in directing the final frameworks. Moreover, the luminescent properties of these two compounds were also investigated in the solid state at ambient temperature.