Spectral, Thermal, Crystal Structure, Hirshfeld Surface Analyses and Biological Activities of New Hydrazinium Dipicolinato Copper(II) Tetrahydrate

A new copper complex of pyridine-2,6-dicarboxylate containing hydrazinium cation, formulated as (N2H5)2[Cu(PDC)2]·4H2O (PDC = pyridine-2,6-dicarboxylate) has been synthesized from copper(II) nitrate, hydrazine hydrate and pyridine-2,6-dicarboxylic acid as a single crystal and characterized by elemental analysis and spectroscopic (IR and UV-visible), thermal (TG/DTG), single crystal X-ray diffraction and biological studies. A six-coordinate complex with a distorted octahedral geometry around Cu(II) ion is proposed and confirmed by X-ray single crystal method. The structure reveals that two pyridine-2,6-dicarboxylate species acting as tridentate ligands and hydrazinium cation present as a counter ion along with non-coordinated four water molecules. The structural units of copper(II) is mutually held by the hydrogen bonds and π···π and C–O···π interactions. The copper(II) complex is connected to one another via O–H···O hydrogen bonds, forming water clusters, which plays an important role in the stabilization of the crystal structure. In the water clusters, the water molecules are trapped by the cooperative association of coordination interactions as well as hydrogen bonds. Both cation and anion interactions and crystal from various types of intermolecular contacts and their importance were explored using Hirshfeld surface analysis. This indicates that O···H/H···O interactions are the superior interactions conforming excessive H-bond in the molecular structure. The interaction of copper(II) complex with calf thymus DNA (CT-DNA) was investigated by electronic absorption spectroscopic technique. The electronic evidence strongly shows that the compound interacts with calf thymus through intercalation with a binding constant of Kb = 5.7 × 104 M–1.

The crystal structure of (C2H9N2)2[Zn3(HPO3)4], a three-dimensional zincophosphite framework containing 16-membered rings templated by the unsymmetrical dimethyl hydrazinium cation

The solution-mediated synthesis and crystal structure of 1,1-dimethylhydrazinium tetraphoshonoatotrizincate, (C2H9N2)2[Zn3(HPO3)4], are described. The anionic [Zn3(HPO3)4]2−framework is built up from alternating ZnO4tetrahedra and HPO3pseudo-pyramids to generate a three-dimensional 4,3-net encapsulating the C2H9N2+cations. The organic cations, which are protonated at their central N atoms, occupy pores delineated by large 16-membered polyhedral rings and interact with the framework by way of N—H...O hydrogen bonds and possible C—H...O interactions. One of the zinc ions lies on a crystallographic twofold rotation axis and all the other atoms lie on general positions. The crystal studied was found to be rotationally twinned about the [001] axis in reciprocal space in a 0.585 (5):0.415 (5) ratio.

The acid adducts hydrazinium 2-hydroxybenzoate–2-hydroxybenzoic acid (1/1) and hydrazinium 3-hydroxy-2-naphthoate–3-hydroxy-2-naphthoic acid (1/1)

The title molecular salts, N2H5+·C7H5O3−·C7H6O3and N2H5+·C11H7O3−·C11H8O3, are acid adducts containing a hydrazinium cation, one molecule of a deprotonated acid and one molecule of a neutral acid. The two compounds contain essentially identical hydrogen-bond networks between the hydrazinium cation and the acid molecules, which define closely comparable two-dimensional layers in the structures. The planes of the aromatic rings within both structures are approximately parallel and the layers are stacked with comparable intermolecular interactions.