One-dimensional zinc(II) polymers with 4,6-dimethyl-1,2,3-triazolo[4,5-d]pyrimidin-5,7-dionato built by bipyridyl-based ligands acting as spacers both in the first and in the second sphere

Three solids formed by the reaction of the hexaaquazinc(II) salt of 4,6-dimethyl-1,2,3-triazolo[4,5-d]pyrimidin-5,7-diona (Hdmax) and the potentially bridging ligands 1,2-bis(4-pyridyl)ethane (bpe), 1,3-bis(4-pyridyl)propane (bpp) and trans-1,2-bis(4-pyridyl)ethene (bpethe) are described. The crystal structure of those containing bpe and bpethe has been solved by X-ray diffraction turning out to be one-dimensional polymers with zigzag (bpe) or linear (bpethe) disposition of the metal atoms. The triazolopyrimidinato anion is in both cases monodentately coordinated through the N atom furthest from the pyrimidine ring whereas the bipyridyl ligands bridge through their N atoms consecutive metal atoms in the polymer. For the bpethe compound, an additional non-coordinated molecule of the spacer per Zn atom is present, accepting H-bonds from coordinated water molecules and linking in this way the one-dimensional chains into a two-dimensional superstructure. Therefore, bpethe acts as spacer both in the first and second coordination spheres.

Graphical abstractOne-dimensional polymeric zinc complexes with bridging bipyridine alkyl ligands (alkyl is ethane, bpe, propane, bpp or ethene, bpethe) and 4,6-dimethyl-1,2,3-triazolo[4,5- d]pyrimidin-5,7-dionato (dmax−) monodentately coordinated through the nitrogen atom at position 2 are presented. For bpe, a zigzag chain is generated. For bpethe, the ligand acts as spacer both in the first and in the second coordination spheres: in the first role, it generates linear chains and, in the second one, it links these chains to generate a two-dimensional polymer.Figure optionsDownload full-size imageDownload as PowerPoint slide