Thiosemicarbazides and their metal complexes have attracted considerable interest because of their biological activities and their flexibility, which allows the ligands to bend and rotate freely to accommodate the coordination geometries of various metal centres. Discrete copper(II) and cadmium(II) complexes have been prepared by crystallization of N-[2-(2-hydroxybenzoyl)hydrazinecarbonothioyl]propanamide (H₃L) with Cu(CH₃COO)₂ or Cd(NO₃)₂ in a dimethylformamide/methanol mixed-solvent system at room temperature, affording the complexes di-μ-acetato-bis{μ₄-1-[(2-oxidophenyl)carbonyl]-2-(propanamidomethanethioyl)hydrazine-1,2-diido}tetracopper(II) dimethylformamide disolvate, [Cu₄(C₁₁H₁₀N₃O₃S)₂(C₂H₃O₂)₂]·2C₃H₇NO, (I), and bis{μ₂-[(2-hydroxyphenyl)formamido](propanamidomethanethioyl)azanido}bis[(4,4′-bipyridine)nitratocadmium(II)] dihydrate, [Cd₂(C₁₁H₁₂N₃O₃S)₂(NO₃)₂(C₁₀H₈N₂)₂]·2H₂O, (II). Complex (I) consists of four Cu^II cations, two μ₄-bridging trianionic ligands and two μ₂-bridging acetate ligands, while complex (II) is composed of two Cd^II cations, two μ₂-bridging monoanionic ligands, two nitrate ligands and two 4,4′-bipyridine ligands. These discrete complexes are connected by hydrogen bonds and van der Waals interactions to form a three-dimensional supramolecular architecture. Compared with (I), the phenolic hydroxy group and hydrazide N atom of the thiosemicarbazide ligand of (II) are not involved in coordination and lead to a binuclear Cd^II complex. This different coordination mode may be attributed to the larger ionic radius of the Cd^II ion compared with the Cu^II ion.

A homochiral helical three-dimensional coordination polymer, poly[[(μ₂-acetato-κ³O,O′:O)(hydroxido-κO)(μ₄-5-nicotinamido-1H-1,2,3,4-tetrazol-1-ido-κ⁵N¹,O:N²:N⁴:N⁵)(μ₃-5-nicotinamido-1H-1,2,3,4-tetrazol-1-ido-κ⁴N¹,O:N²:N⁴:N⁵)dicadmium(II)] 0.75-hydrate], {[Cd₂(C₇H₅N₆O)₂(CH₃COO)(OH)]·0.75H₂O}_n, was synthesized by the reaction of cadmium acetate, N-(1H-tetrazol-5-yl)isonicotinamide (H-NTIA), ethanol and H₂O under hydrothermal conditions. The asymmetric unit contains two crystallographically independent Cd^II cations, two deprotonated 5-nicotinamido-1H-1,2,3,4-tetrazol-1-ide (NTIA⁻) ligands, one acetate anion, one hydroxide anion and three independent partially occupied water sites. The two Cd^II cations, with six-coordinated octahedral and seven-coordinated pentagonal bipyramidal geometries are located on general sites. The tetrazole group of one symmetry-independent NTIA⁻ ligand links one of the independent Cd^II cations into 6₁ helical chains, while the other NTIA⁻ ligand links the other independent Cd^II cations into similar but unequal 6₁ helical chains. These chains, with a pitch of 24.937 (5) Å, intertwine into a double-stranded helix. Each of the double-stranded 6₁ helices is further connected to six adjacent helical chains through an acetate μ₂-O atom and the tetrazole group of the NTIA⁻ ligand into a three-dimensional framework. The helical channel is occupied by the isonicotinamide groups of NTIA⁻ ligands and two helices are connected to each other through the pyridine N and carbonyl O atoms of isonicotinamide groups. In addition, N—H...O and O—H...N hydrogen bonds exist in the complex.

The title complex, [Cu(C₆H₄N₃)]_n, was synthesized by the reaction of cupric nitrate, 1H-benzotriazole (BTAH) and aqueous ammonia under hydrothermal conditions. The asymmetric unit contains three crystallographically independent Cu^I cations and two 1H-benzotriazolate ligands. Two of the Cu^I cations, one with a linear two-coordinated geometry and one with a four-coordinated tetrahedral geometry, are located on sites with crystallographically imposed twofold symmetry. The third Cu^I cation, with a planar three-coordinated geometry, is on a general position. Two Cu^I cations are doubly bridged by two BTA⁻ ligands to afford a noncentrosymmetric planar [Cu₂(BTA)₂] subunit, and two [Cu₂(BTA)₂] subunits are arranged in an antiparallel manner to form a centrosymmetric [Cu₂(BTA)₂]₂ secondary building unit (SBU). The SBUs are connected in a crosswise manner via the sharing of four-coordinated Cu^I cations, Cu—N bonding and bridging by two-coordinate Cu^I cations, resulting in a one-dimensional chain along the c axis. These one-dimensional chains are further linked by C—H...π and weak van der Waals interactions to form a three-dimensional supramolecular architecture.

The title coordination polymer, {[Cd₂(CH₂N₅)(C₆H₄NO₂)Cl(OH)]·0.14H₂O}_n, (I), was synthesized by the reaction of cadmium acetate and N-(1H-tetrazol-5-yl)isonicotinamide in aqueous ammonia, using hydrochloric acid to adjust the pH. Under hydrothermal conditions, N-(1H-tetrazol-5-yl)isonicotinamide slowly hydrolyzes to form isonicotinic acid (Hisonic) and 5-aminotetrazole (Hatz). The deprotonated form of isonicotinic acid (denoted isonic) acts as a bridging ligand in the structure. The polymer crystallizes in the monoclinic space group C2/m. In the structure, there is one Cd₃(μ₃-OH) unit of C_s symmetry, with one of the Cd^II atoms and the O and H atoms located on a mirror plane. The other crystallographically independent Cd^II cation is located on an inversion centre. Each edge of the Cd₃(μ₃-OH) isosceles triangle is bridged by an atz ligand in a μ_1,2 or μ_2,3/μ_3,4 mode. The Cd₃(μ₃-OH) units are laced around with a belt of chloride ligands. The belts are further connected into undulating layers via weak inter-belt Cd—Cl bonds. The two organic ligands reside across mirror planes. The construction of a three-dimensional framework is completed by the pillaring isonic ligand. Water molecules partially occupy the voids of the framework.