Complexes of cytotoxic chelators from the dipyridyl ketone isonicotinoyl hydrazone (HPKIH) analogues

New nano-complexes targeting protein 3S7S in breast cancer and protein 4OO6 in liver cancer investigated in cell line

Cancer, a lethal ailment, possesses a multitude of therapeutic alternatives to combat its presence, metal complexes have emerged as significant classes of medicinal compounds, exhibiting considerable biological efficacy, especially as anticancer agents. The utilization of cis-platin in the treatment of various cancer types, including breast cancer, has served as inspiration to devise novel nanostructured metal complexes for breast cancer therapy. Notably, homo- and hetero-octahedral bimetallic complexes of an innovative multifunctional ether ligand (comprising Mn(II), Ni(II), Cu(II), Zn(II), Hg(II), and Ag(I) ions) have been synthesized. To ascertain their structural characteristics, elemental and spectral analyses, encompassing IR, UV-Vis, 1H-NMR, mass and electron spin resonance (ESR) spectra, magnetic moments, molar conductance, thermal analysis, and electron microscopy, were employed. The molar conductance of these complexes in DMF demonstrated a non-electrolytic nature. Nanostructured forms of the complexes were identified through electron microscopic data. At ambient temperature, the ESR spectra of the solid complexes exhibited anisotropic and isotropic variants, indicative of covalent bonding. The ligand and several of its metal complexes were subjected to cytotoxicity testing against breast cancer protein 3S7S and liver cancer protein 4OO6, with the Ag(I) complex (7) evincing the most potent effect, followed by the Cu(II) with ligand (complex (2)), Cis-platin, the ligand itself, and the Cu(II)/Zn(II) complex (8). Molecular docking data unveiled the inhibitory order of several complexes.

Evaluating the role of a urea-like motif in enhancing the thermal and mechanical strength of supramolecular gels

Enhanced thermal and mechanical strength in semicarbazone gels with a urea-like motif obtained by modifying the hydrogen bonding motif of the hydrazone compound.

Heterometallic coordination polymers: Treatment activity on diabetic foot by reducing the excess inflammatory response in the plantar tissue

Two new heterometallic coordination polymers formulated as {[LaCo(2.5-pydc)2(H2O)4]Cl·4H2O}n (1, 2,5-H2pydc = pyridine-2,5-dicarboxylic acid) and {[LaCo2Cl3(4,4′-bpdc)2(H2O)3]·H2O}n (2, 4,4′-H2bpdc = 2,2′-bipyridyl-4,4′-dicarboxylic acid) have been solvothermally synthesized using the coordination between rare earth/transition metal ions and pyridinedicarboxylic acids. To develop new candidates for enhancing the therapeutic effect of improved negative pressure suction for diabetic foot, the activities of compounds 1 and 2 were studied. First, the ELISA (enzyme linked immunosorbent assay) detection kit was used and the inflammatory cytokines in the plantar tissue were measured. Besides, the TLR-4-NF-κB signaling pathway was measured with real-time reverse transcription-polymerase chain reaction.

Crystal structure of the mixed methanol and ethanol solvate of bis-{3,4,5-trimeth-oxy-N'-[1-(pyridin-2-yl)ethyl-idene]benzohydrazidato}zinc(II)

The unit cell of the title compound, [Zn(C17H18N3O4)2]·CH4O·C2H6O, contains two complex mol-ecules related by an inversion centre, plus one methanol and one ethanol solvent molecule per complex molecule. In each complex, two deprotonated pyridine aroylhydrazone ligands {3,4,5-trimeth-oxy-N'-[1-(pyridin-2-yl)ethyl-idene]benzohydrazide} coordinate to the ZnII ion through the N atoms of the pyridine group and the ketamine, and, additionally, through the O atom of the enolate group. In the crystal, dimers are formed by π-π inter-actions between the planar ligand moieties, which are further connected by C⋯O and C⋯C inter-actions. The inter-molecular inter-actions were investigated using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing that the most important contributions for the crystal packing are from H⋯H (44.8%), H⋯C/C⋯H (22.2%), H⋯O/O⋯H (18.7%) and C⋯C (3.9%) inter-actions.

Vapour- and solvent-mediated crystalline transformations in Mo(vi) hydrazone complexes controlled by noncovalent interactions

Through the use of hydrogen bond driven solid-state synthesis, mononuclear complexes are transformed into crystalline materials.

Three novel transition metal complexes of 6-methyl-2-oxo-quinoline-3-carbaldehyde thiosemicarbazone: synthesis, crystal structure, cytotoxicity, and mechanism of action

Complex 1 was more selective for MGC80-3 tumor cells versus normal cells (HL-7702). Importantly, 1 triggered MGC80-3 cells apoptosis via a mitochondrial dysfunction pathway.

Synthesis of Dipyridyl Ketone Isonicotinoyl Hydrazone Copper(II) Complex: Structure, Anticancer Activity and Anticancer Mechanism

In an effort to better understand the biological efficacy of the tridentate aroyl hydrazone Cu(II) complexes, the Cu(II) complex of di-2-pyridyl ketone isonicotinoyl hydrazone ligand (HL), {[Cu(L)(H₂O)]·H₂O·NO₃}_n (C1) was synthesized and characterized. Single crystal X-ray study reveals that complex C1 forms 1D zigzag chains in solid state. In water, the hydrolysis of the 1D zigzag chains was observed, and finally formation of monomeric species. In vitro studies revealed that complex C1 showed significantly more anticancer activity than the ligand alone. Investigation of the anticancer mechanisms of C1, confirmed that the Cu(II) complex exhibit a strong capacity to promote productions of reactive oxygen species (ROS), leading to caspase-dependent apoptotic cell death.

α-N-heterocyclic thiosemicarbazone Fe(III) complex: Characterization of its antitumor activity and identification of anticancer mechanism

We synthesized an α-N-heterocyclic thiosemicarbazone ligand (L) and its Fe complex (C1) and assessed their chemical and biological properties in order to understand their marked activity. Electrochemical studies and ascorbate oxidation studies demonstrated that C1 shows considerable redox activity, and Fe(III/II) redox potentials was within the range accessible to cellular oxidants and reductants. Absorption spectral, emission spectral and viscosity analysis reveal that L and C1 interacted with DNA through intercalation and C1 exhibited a higher DNA binding ability. Agarose gel electrophoresis experiments indicated that C1 exhibited the highest pBR322 DNA cleaving ability. In vitro, C1 showed significantly more anticancer activity than the ligand alone. Moreover, C1 induces production of reactive oxygen species (ROS) and DNA damage, resulting in activation of the p53 pathway, cell cycle arrest at the S phase, and mitochondria-mediated apoptosis by regulating the expression of Bcl-2 family proteins.

The Cu/ligand stoichiometry effect on the coordination behavior of aroyl hydrazone with copper(II): Structure, anticancer activity and anticancer mechanism

In an effort to better understand the biological efficacy of the tridentate aroyl hydrazone Cu(II) complexes, three Cu(II) complexes of acetylpyridine benzoyl hydrazone (HL), [Cu(L)(NO3) (H2O)]·H2O (C1), [Cu(L)2] (C2) and [Cu(L)(HL)]·(NO3)(Sas) (C3) (Sas=salicylic acid) were synthesized and characterized. X-ray crystal structures and infrared (IR) spectra of the complexes reveal that the L(-) ligand of C1 and C2 are predominantly in the enolate resonance form, while one L(-) ligand in C3 is represented enolate resonance form and the other HL ligand exhibits keto resonance form. All Cu(II) complexes showed significantly more anticancer activity than the ligand alone. Interestingly, the Cu complexes where the ligand/metal ratio was 1:1 (C1) rather than 2:1 (C2 and C3) had higher antitumor efficacy. Moreover, the 1:1 Cu/ligand complex, C1, promotes A549 cell apoptosis possibly through the intrinsic reactive oxygen species (ROS) mediated mitochondrial pathway, accompanied by the regulation of Bcl-2 family proteins.

Tuning the thermotropic properties of liquid crystalline p-substituted aroylhydrazones

Lamellar smectic A to columnar mesophase crossover is observed in p-substituted aroylhydrazones by variation of the alkoxy chain density at peripherals.

Cobalt(iii) complexes with tridentate hydrazone ligands: protonation state and hydrogen bond competition

Differently protonated ligands in [Co(HL)(L)] are stabilizedviasupramolecular assembling through O–H⋯O/N and N–H⋯N/O hydrogen bonding. Channels spreading either in each space dimension or predominantly in one direction are formed.

Redox-active porous coordination polymers prepared by trinuclear heterometallic pivalate linking with the redox-active nickel(II) complex: synthesis, structure, magnetic and redox properties, and electrocatalytic activity in organic compound dehalogenation in heterogeneous medium

Linking of the trinuclear pivalate fragment Fe2CoO(Piv)6 by the redox-active bridge Ni(L)2 (compound 1; LH is Schiff base from hydrazide of 4-pyridinecarboxylic acid and 2-pyridinecarbaldehyde, Piv(-) = pivalate) led to formation of a new porous coordination polymer (PCP) {Fe2CoO(Piv)6}{Ni(L)2}1.5 (2). X-ray structures of 1 and 2 were determined. A crystal lattice of compound 2 is built from stacked 2D layers; the Ni(L)2 units can be considered as bridges, which bind two Fe2CoO(Piv)6 units. In desolvated form, 2 possesses a porous crystal lattice (SBET = 50 m(2) g(-1), VDR = 0.017 cm(3) g(-1) estimated from N2 sorption at 78 K). At 298 K, 2 absorbed a significant quantity of methanol (up to 0.3 cm(3) g(-1)) and chloroform. Temperature dependence of molar magnetic susceptibility of 2 could be fitted as superposition of χMT of Fe2CoO(Piv)6 and Ni(L)2 units, possible interactions between them were taken into account using molecular field model. In turn, magnetic properties of the Fe2CoO(Piv)6 unit were fitted using two models, one of which directly took into account a spin-orbit coupling of Co(II), and in the second model the spin-orbit coupling of Co(II) was approximated as zero-field splitting. Electrochemical and electrocatalytic properties of 2 were studied by cyclic voltammetry in suspension and compared with electrochemical and electrocatalytic properties of a soluble analogue 1. A catalytic effect was determined by analysis of the catalytic current dependency on concentrations of the substrate. Compound 1 possessed electrocatalytic activity in organic halide dehalogenation, and such activity was preserved for the Ni(L)2 units, incorporated into the framework of 2. In addition, a new property occurred in the case of 2: the catalytic activity of PCP depended on its sorption capacity with respect to the substrate. In contrast to homogeneous catalysts, usage of solid PCPs may allow selectivity due to porous structure and simplify separation of product.

2-Acetylpyridine thiosemicarbazones are potent iron chelators and antiproliferative agents: redox activity, iron complexation and characterization of their antitumor activity

Through systematic structure-activity studies of the 2-benzoylpyridine thiosemicarbazone (HBpT), 2-(3-nitrobenzoyl)pyridine thiosemicarbazone (HNBpT) and dipyridylketone thiosemicarbazone (HDpT) series of iron (Fe) chelators, we identified structural features necessary to form Fe complexes with potent anticancer activity (J. Med. Chem. 2007, 50, 3716-3729). In this investigation, we generated the related 2-acetylpyridine thiosemicarbazone (HApT) analogues to examine the influence of the methyl group at the imine carbon. Four of the six HApT chelators had potent antitumor activity (IC(50): 0.001-0.002 microM) and Fe chelation efficacy that was similar to the most effective HBpT and HDpT ligands. The HApT Fe complexes had the lowest Fe(III/II) redox potentials of any thiosemicarbazone series we have generated. This property, in combination with their ability to effectively chelate cellular Fe, make the HApT series one of the most potent antiproliferative agents developed by our group.

Dibut-yl{N'-[1-(5-chloro-2-oxidophenyl-κO)ethyl-idene]-3-hy-droxy-2-naphtho-hydrazidato-κN',O}tin(IV)

The five-coordinate Sn^IV atoms in the two crystallographically independent mol­ecules of the title compound, [Sn(C₄H₉)₂(C₁₉H₁₃ClN₂O₃)], are in distorted cis-C₂NO₂Sn trigonal-bipyramidal coordination environments. The tridentate dianion of the Schiff base, N′-[1-(5-chloro-2-oxidophen­yl)ethyl­idene]-3-hy­droxy-2-naphtho­hydrazide, displays inter­molecular O—H⋯N hydrogen bonding, which stabilizes the overall compound.

Iron chelators of the dipyridylketone thiosemicarbazone class: precomplexation and transmetalation effects on anticancer activity

We previously reported a series of di-2-pyridylketone thiosemicarbazone (HDpT) chelators that showed marked and selective antitumor activity (Whitnall, M.; et al. Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 14901-14906). To further understand their biological efficacy, we report the characterization and activity of their Mn(II), Co(III), Ni(II), Cu(II), and Zn(II) complexes. The X-ray crystal structures of four divalent (Mn, Ni, Cu, and Zn) and one trivalent (Fe) complexes are reported. Electrochemistry shows the Fe(III/II) and Cu(II/I) potentials of the complexes may be redox-active within cells. Stability constants were also determined for the Mn(II), Ni(II), Cu(II), and Zn(II) complexes. All divalent complexes underwent transmetalation upon encountering Fe(II), to form low spin ferrous complexes. Importantly, the divalent Mn(II), Ni(II), Cu(II), and Zn(II) complexes of the HDpT analogues are equally active in preventing proliferation as their ligands, suggesting the complexes act as lipophilic vehicles facilitating intracellular delivery of the free ligand upon metal dissociation.