Structural diversity of terpyridine-based metal complexes with varied dicarboxylate auxiliary ligands

Six new metal complexes, [Zn2L2(1,2-bdc)2] (1), [CuZnL2(1,2-bdc)2] (2), {[Cu2L(1,3-bdc)2]·2H2O}n (3), {[Cu2L2(1,4-bdc)](NO3)2·2H2O}n (4), [Cu2L2(1,4-bdc)(SCN)2]·2H2O (5) and {[ZnL(dc)]·H2O}n (6), have been synthesized by the reactions of 4′-4-(1,2,4-triazol-1-yl)-phenyl-2,2′:6′,2″-terpyridine (L) and different dicarboxylate auxiliary ligands with the corresponding metal salt. Complexes 1 and 2, with 1,2-benzenedicarboxylate (1,2-bdc2−), have dinuclear molecular structures. Complex 3, with 1,3-benzenedicarboxylate (1,3-bdc2−), is a (3,3,4)-connected three-dimensional (3D) framework with a Point (Schläfli) symbol of (4.6.8)(4.6.8)(6.84.10), while 4, with 1,4-benzenedicarboxylate (1,4-bdc2−), has an infinite chain structure, and further addition of SCN− anions to 4 results in the formation of the dinuclear complex 5. When 1,4-benzenediacrylic acid (H2dc) was employed as auxiliary ligand, complex 6 was obtained, having an infinite zigzag chain structure. All the complexes were characterized by elemental analyses, IR and X-ray crystallography. The results showed that the nature of the auxiliary ligand has a great impact on the structure of the complexes. Furthermore, the photoluminescence of the Zn(II) complexes and the reversible anion exchange property of 4 were investigated.

Graphical abstractThe hydrothermal reactions of metal nitrates and a terpyridine derivative ligand with different dicarboxylate auxiliary ligands resulted in the formation of six new coordination compounds 1–6. The photoluminescence and ion exchange properties of the complexes were investigated.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Complexes with a terpyridine derivative ligand. ► The structural diversity depends on the dicarboxylate auxiliary ligand. ► Photoluminescence and anion exchange properties of the complex.