A novel cationic complex, bromidotetrakis[5-(prop-2-en-1-ylsulfanyl)-1,3,4-thiadiazol-2-amine-κN ³]copper(II) bromide, [CuBr](C₅H₇N₃S₂)₄Br, was synthesized. The complex crystallizes with fourfold molecular symmetry in the tetragonal space group P4/n. The Cu^II atom exhibits a square-pyramidal coordination geometry. The Cu atom is located centrally within the complex, being coordinated by four nitrogen atoms from four AAT molecules, while a bromine anion is located at the apex of the pyramid. The amino H atoms of AAT interact with bromine from the inner and outer spheres, forming a two-dimensional network in the [100] and [010] directions. Hirshfeld surface analysis reveals that 33.7% of the intermolecular interactions are from H...H contacts, 21.2% are from S...H/H...S contacts, 13.4% are from S...S contacts and 11.0% are from C...H/H...C, while other contributions are from Br...H/H...Br and N...H/H...N contacts.

A new zinc coordination polymer with 5-phenyl-1,3,4-oxadiazole-2-thiolate, namely, catena-poly[zinc(II)-bis(μ₂-5-phenyl-1,3,4-oxadiazole-2-thiolato)-κ² N ³:S;κ² S:N ³], [Zn(C₈H₅N₂OS)₂] _n , was synthesized. The single-crystal X-ray diffraction analysis shows that the polymeric structure crystallizes in the centrosymmetric monoclinic C2/c space group. The Zn^II atom is coordinated to two S and two N atoms from four crystallographically independent (L) ligands, forming zigzag chains along the [001] direction. This polymer complex forms an eight-membered [Zn–S–C–N–Zn–S–C–N] chair-like ring with two Zn^II atoms and two ligand molecules. On the Hirshfeld surface, the largest contributions come from the short contacts such as van der Waals forces, including H...H, C...H and S...H. Interactions including N...H, O...H and C...C contacts were also observed; however, their contribution to the overall stability of the crystal lattice is minor.

The new organic salt, 2-aminobenzoxazol-3-ium 3-carboxyprop-2-enoate, C₇H₇N₂O⁺·C₄H₃O₄ ⁻, of the two bioactive compounds 2-aminobenzoxazole and fumaric acid, crystallizes in the orthorhombic space group Pbca using classical evaporation of their solution in water. The usual topological analysis revealed four classical (N—H...O and O—H...O) and two non-classical (C—H...O) hydrogen bonds in the structure. Stacking was found as well for a pair of 2-aminobenzoxazolium cations. A Hirshfeld surface analysis including the two-dimensional fingerprint plots was performed to define the residual π–π interactions and to quantify the influences of different types of interactions by means of topological analysis. Analysis of the pairwise interaction energies was used to prove the formation of the corrugated paired layers of cation–anion dimers parallel to the plane (001) as a basic structural motif in the topological, as well as in the energetic structure of the crystal. It showed that the layers are connected by the hydrogen bonds inside and by stacking and π–π interactions and general dispersion between them.

In the title coordination complex, (C₄H₈N₃S₂)₂[Cu(C₆H₄NO₂)₂(ClO₄)₂], the Cu^II center exhibits a distorted octahedral geometry with an equatorial plane formed by two bidentate picolinato ligands and axial coordination from two perchlorate anions, consistent with a Jahn–Teller distortion. The crystal structure is further consolidated by a network of hydrogen bonds involving the thiadiazole-based cations, which reside in the outer coordination sphere in a unique protonated state. Hirshfeld surface analysis reveals that O...H/H...O contacts dominate the intermolecular interactions, contributing significantly to the crystal packing.