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The overall molecular configuration of the title compound, C12H16N6OS2·C3H7NO, is stabilized in the solid state by intramolecular C—H...N, C—H...O, N—H...N and N—H...O interactions, forming S(5) ring motifs. In the crystal, molecules are linked to each other and solvent dimethylformamide molecules by N—H...S, N—H...O, C—H...O and C—H...S hydrogen bonds, forming a three dimensional network. The phenyl ring of the title compound is disordered over two sites with an occupancy ratio of 0.57 (4):0.43 (4). A Hirshfeld surface analysis was performed to quantify the contributions of the different intermolecular interactions, indicating that the most important contributions to the crystal packing are from H...H (38.7%), S...H / H...S (24.0%), C...H / H...C (18.5%) and N...H / H...N (9.8%) interactions.

Copper(II) acetate reacted with 2,3-isatin bisthiosemicarbazone (2,3 H2bitsc), 2,3-isatin bis-N1-methyl thiosemicarbazone (2,3 H2bitsc-N1-Me) and 2,3-isatin N1-phenyl thiosemicarbazone (2,3 H2bitsc-N1-Ph) in 1:1 (M: L) to form complexes of formula, [Cu(L)] (L = 2,3 bitsc 1, 2,3 bitsc-N1-Me 2, 2,3 bitsc-N1-Ph 3). The formation of bisthiosemicarbazone ligands and their complexes are supported by elemental analysis, FTIR, NMR (1H and 13C), ESR, and Mass. For complexes 1–3, two g values obtained are: g‖ = 2.24 (1), 2.17 (2), 2.26 (3) and g⊥ = 2.09 (1), 2.11 (2), 2.08 (3) which confirm axial symmetry. The square planar geometry is confirmed from higher g‖ values than g⊥ and presence g value of free electron in dx2-y2 ground term. Ligand to metal binding ratio of 1:1 is confirmed using UV–visible spectroscopy. The ligands (2,3 H2bitsc, 2,3 H2bitsc-N1-Me and 2,3 H2bitsc-N1-Ph) and complexes (1–3) were assessed for anti-tubercular (M. tuberculosis H37RV strain ATCC27294) and antibacterial (against E. coli and S. aureus) activities. The anti- tuberculosis activity of ligands (50 µg/mL-2,3 H2bitsc, 100 µg/mL-2,3 H2bitsc-N1-Me and H2bitsc-N1-Ph) gets enhanced on complexation with copper (25 µg /mL-1, 50 µg/mL 2 and 3). The minimal binding energies calculated through molecular modeling with mycobacterium tuberculosis enoyl reductase (PDB ID: 2H7M) is −7.6 (2,3 H2bitsc), −7.3 (2,3 H2bitsc-N1-Me), −9.6 (2,3 H2bitsc-N1-Ph), −8.7 (1), −8.9 (2), and −10.7 (3) Kcal/mol. Higher negative binding energy indicates more stabilized structure in the docked state for 1–3 which supports the experimental data. The drug-protein binding study with human serum albumin (HSA) was used to explore effective transport of molecules to their target sites in 2,3 H2bitsc and its complex 1. A high binding constant of complex 1 (6.09 × 105 M−1) with respect to the ligand 2,3 H2bitsc (4.90 × 105 M−1) indicates its strong binding affinities with HSA.

The overall molecular configuration of the title compound, C12H16N6OS2•C3H7NO, is stabilized in the solid state by intramolecular C--H• • •N, C--H• • •O, N--H• • •N and N--H• • •O interactions, forming S(5) ring motifs. In the crystal, molecules are linked to each other and solvent dimethylformamide molecules by N--H• • •S, N--H• • •O, C--H• • •O and C--H• • •S hydrogen bonds, forming a three dimensional network. The phenyl ring of the title compound is disordered over two sites with an occupancy ratio of 0.57 (4):0.43 (4). A Hirshfeld surface analysis was performed to quantify the contributions of the different intermolecular interactions, indicating that the most important contributions to the crystal packing are from H• • •H (38.7%), S• • •H / H• • •S (24.0%), C• • •H / H• • •C (18.5%) and N• • •H / H• • •N (9.8%) interactions. [ABSTRACT FROM AUTHOR]

The increase in the investigation of different self-assembled architectures derived from thiosemicarbazone ligands can be attributed to the numerous functional metallosupramolecular architectures with practical applications that can be obtained. The potentially tetradentate organic bisthiosemicarbazone ligand H2L possesses two flexible bidentate [NS] domains separated by a short and rigid spacer, which could stabilize several metal ions and thus different metallosupramolecular architectures. H2L was prepared by the reaction between two equivalents of N-ethylhydrazinecarbothioamide and one equivalent of 1,1′,1″-(benzene-1,3,5-triyl)tris(ethan-1-one) and was fully studied using several techniques, including X-ray diffraction.

In this work, we present the design and synthesis of the bisthiosemicarbazone ligand H3LMe by means of an iminic condensation reaction between 2-hydroxyisophthalaldehyde and 4-methyl-3-thiosemicarbazide. This ligand is bicompartmental, pentadentate [N2S2O] and potentially trianionic. The presence of a spacer constituted by a phenol group facilitates the coordination of transition metal ions, giving rise to a great variety of structures. To confirm the purity of the ligand, different characterization techniques were employed, including elemental analysis, mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance. The acquisition of suitable crystals of H3LMe allowed us to analyze its structure through X-ray diffraction studies.

A potentially dianionic symmetric bisthiosemicarbazone ligand H2LEt has been prepared by a condensation reaction between two equivalents of 4-N-ethyl-3-thiosemicarbazide and one equivalent of 4,4′-methylenebis(acetophenone). The crystal structures obtained from solvents with different donor abilities were studied. The recrystallization of H2LEt from methanol and dimethylsulfoxide enables the isolation of single crystals suitable for the X-ray diffraction studies of [H2LEt] 1 and [H2LEt]·CH3SOCH32, respectively. This study shows that the solvent does not affect the macrostructure but influences the microstructure of the ethyl-substituted bisthiosemicarbazone ligand H2LEt.

Abstract: The synthesis of three bis(thiosemicarbazone) compounds formed by the reaction of benzil with either thiosemicarbazide, 4-methyl-3-thiosemicarbazide or 4-phenyl-3-thiosemicarbazide are reported. The compounds were characterised by NMR spectroscopy, mass spectrometry and in the case of benzil bis(4-methyl-3-thiosemicarbazone) and benzil bis(4-phenyl-3-thiosemicarbazone) by X-ray crystallography. Attempts to purify benzil bis(thiosemicarbazone) and benzil bis (4-methyl-3-thiosemicarbazone) by recrystallisation resulted in the isolation of cyclised products that were characterised by X-ray crystallography. The 3 bis(thiosemicarbazone) compounds were used to synthesise both Cu(II) and Cu(I) complexes. The copper(II) complexes were formed by the reaction of the proligands with copper(II) acetate which gave neutral copper(II) complexes in which the thiosemicarbazone is doubly deprotonated, acting as a dianionic ligand. The copper(II)-benzil bis(4-phenyl-3-thiosemicarbazonato) complex was characterised by X-ray crystallography to show the copper in an essentially square planar N2S2 environment. The copper(I) complexes were synthesised by reacting the bis (thiosemicarbazone) ligands with [Cu(CH3CN)4]PF6 to give cationic complexes. The copper(I)-benzil-bis(thiosemicarbazone) complex was characterised by X-ray crystallography which revealed that the complex was a dimeric dication. Each of the benzil bis(thiosemicarbazone) ligands act as a bidentate N,S donor to each copper(I) atom, forming an overall helical structure in which each copper atom is in a strongly distorted tetrahedral N2S2 environment. Electrochemical measurements show that the copper(II)-benzil bis(thiosemicarbazonato) complex undergoes a reversible reduction at biologically accessible potentials. [Copyright &y& Elsevier]