Synthesis and antimicrobial activity of tridentate thiobenzoylhydrazone complexes

Design, Synthesis, and Characterization of New Iron Chelators with Anti-Proliferative Activity: Structure−Activity Relationships of Novel Thiohydrazone Analogues

“…This conforms with the idea that multiple species of these chelators exist in solution and agrees with previous studies examining other thiohydrazones. [49][50][51]56,57 Moreover, it is the monomeric, noncyclic form of the ligand that acts to effectively bind Fe.…”

“…It is known that dihydrothiadiazoles may equilibrate with their Schiff base precursors in solution, [53][54][55] thus enabling them to act as metal ion chelators. 56,57 This point is important to consider and suggests that the biological activity of these ligands described below is actually due to a similar reversible interconversion. This reaction leads to the noncyclic tridentate ligand which then acts as a biologically effective Fe chelator.…”

“…As previously mentioned, cyclic dihydrothiadiazole analogues have been shown to form metal complexes where the ligand is able to revert to its acyclic Schiff base form. 56,57 The 1 H NMR spectra of these ferrous complexes were obtained showing sharp peaks indicating that their Fe complexes were in the low-spin state in solution. Elemental analysis indicated that the compounds were charge neutral 1:2 Fe II /ligand complexes without any counter ions, which requires both ligands to be bound in their singly deprotonated form.…”

“…Collectively, our data strongly supports the hypothesis that multiple species of these chelators exist in solution and agrees with previous studies examining other thiohydrazones. [49][50][51]56,57 Moreover, it is the acyclic, monomeric form of these compounds that acts as an effective ligand. In fact, the disulfide dimer of H 2 STBH and cyclized form of HPKTBH could not be expected to act as biologically potent Fe chelators, as disruption of tridentate binding in this general class of ligands leads to inhibition of Fe chelation activity.…”

Study of the Relationship between Chemical Structure and Antimicrobial Activity in a Series of Hydrazine-based Coordination Compounds

“…These compounds can be viewed as analogs of the cell growth factor, namely, the complex of Cu(II) and glycil-histidil-lysine tripeptide, i.e. as its anti-metabolites suppressing the growth of cells [3,4]. The purpose of the communication is theoretical investigation of the nature of both organic ligand and the metal influence on the anti-microbial (antistaphylococcus) activity demonstration and a system of prognostication design that is capable of purposeful synthesis of high-active compounds belonging to the class discussed.…”