Independent Zinc Research Articles

Catena-Poly[[μ3-hydroxido-tetra-μ2-pyridazine-1:2κ4N:N′;1:3κ2N:N′;2:3κ2N:N′-tetrakis(selenocyanato)-1κN,2κN,3κ2N-trizinc(II)]-μ-cyanido-1:2′κ2C:N

In the crystal structure of the title compound, [Zn3(NCSe)4(OH)(CN)(C4H4N2)4]n one of the two crystallograph­ically independent zinc(II) cations is coordinated by two terminal N-bonded seleno­cyanato anions and two N atoms of two symmetry-related pyridazine ligands in a trigonal-bipyramidal geometry, while the other zinc(II) cation is coordinated by one terminal N-bonded seleno­cyanato anion, one μ-1,2-cyanido anion and three N atoms of three crystallographically independent pyridazine ligands in a slightly distorted octa­hedral coordination geometry. The zinc(II) atoms are further connected via a μ3-hydroxido anion into trinuclear building blocks. The formula unit consists of three zinc cations, four seleno­cyanato anions, one μ3-hydroxido anion, four pyridazine mol­ecules as well as one cyanido anion. The asymmetric unit contains half of a formula unit. One of the zinc atoms, two seleno­cyanato anions, two pyridazine ligands and the μ3-hydroxido anion are located on a crystallographic mirror plane, whereas the cyanido anion is located on a twofold rotation axis. Therefore, this anion is disordered due to symmetry. The cyanido anions connect the metal centres into polymeric zigzag chains propagating along the a axis.

Cubane-like water clusters in a 3D supramolecular network of zinc with pyridine-2,6-dicarboxylic acid and 5-aminotetrazole

The reaction of zinc ions with pyridine-2,6-dicarboxylic acid (H 2PDA) and 5-aminotetrazole (HATZ) in hydrothermal condition gives rise to a 2D interdigitated network of composition [Zn 2(PDA)(ATZ) 2]·4H 2O ( 1). The two independent zinc(II) ions, both located on a crystallographic twofold axis, show a different coordination environment, namely a highly distorted trigonal bipyramidal and a tetrahedral geometry. An octameric cluster of lattice water molecules in the lattice voids produces a 3D supramolecular architecture through hydrogen bonding. Thermogravimetry, infrared spectra, and elemental analysis have also been applied to characterize 1. Fluorescence study indicates the intraligand π–π ∗ transition perturbed by the metal ion.