Mixed-ligand metallosupramolecular complexes with Brn-terephthalic acid (n = 1 or 4) and a versatile bent dipyridyl tecton: Structural modulation by substituent effect of the ligand and metal ion

This work presents a series of ZnII, CdII, CoII, and PbII supramolecular complexes assembled from a bent dipyridyl derivative 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) and different dicarboxyl co-ligands 2-bromoterephthalic acid (H2BTA) and tetrabromoterephthalic acid (H2TBTA). All products have been prepared under similar conditions and characterized by IR, microanalysis, and TG–DTA techniques. Single-crystal X-ray diffraction indicates that these complexes display mononuclear, 1-D, and 2-D coordination motifs, and diverse higher-dimensional extended networks are further constructed via additional secondary interactions such as H-bonding and aromatic stacking. Notably, in situ hydrolysis reaction of 3-bpo is observed in the PbII complex with H2TBTA, affording another dipyridyl-type ligand N,N′-bis(3-picolinoyl)hydrazine (3-bph). These results evidently reveal the significant substituent effect of terephthalic acid in structural direction of these metallosupramolecular systems that are also regulated by the selection of metal ions.

This work reports a series of ZnII, CdII, CoII, and PbII complexes with Brn-terephthalic acid (n = 1 or 4) and a versatile bent dipyridyl tecton, which display diversiform coordination motifs and metallosupramolecular architectures that are regulated by substituent effect of the ligands as well as metal ions.Figure optionsDownload as PowerPoint slide