Co and Cu complexes with 2-acetylpyridine-4-hydroxy phenylacetyl acylhydrazone: Synthesis, crystal structures, CT-DNA/BSA binding behaviors, antibacterial activities and molecular docking studies

Synthesis, spectral characterization of pyrazole derived Schiff base analogs: molecular dynamic simulation, antibacterial and DNA binding studies

We have synthesized the pyrazole-bearing Schiff base derivatives (5a-5e) and (6a-6h) then the structural confirmation was supported by various spectral analyses. The antibacterial activity of all analogs was screened against bacterial strains Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Klebsiella pneumonieae and Pseudomonas aeruginosa. In comparison to the reference drug ciprofloxacin, the lead analogs 5c and 6c showed potent activity, with MIC values of 64 µg/mL against E. coli and B. subtilis. Compound 5c showed a moderate effect with a MIC value of 128 µg/mL against B. subtilis, P. aeruginosa and K. pneumonieae, while compound 6c was against E. coli and P. aeruginosa. Furthermore, the compounds 5c and 6c displayed groove binding mode towards CT-DNA by absorption, emission, competitive fluorescence studies using EtBr, CD and time-resolved fluorescence studies. Thermodynamic parameters of analogs 5c and 6c with CT-DNA were also calculated at 298, 303 and 308K temperatures by UV-visible spectroscopy. The molecular docking studies give the docking score for all compounds with PDB codes: 1BNA and 2XCT. The MD simulation study of analogs 5c and 6c was also carried out. The pharmacokinetic and ADME properties were calculated for all of the synthesized analogs (5a-5e) and (6a-6h).Communicated by Ramaswamy H. Sarma.

Three water-soluble acylhydrazone tetranuclear transition metal complexes: Crystal structures, DNA/BSA interactions and cytotoxicity studies

2-acetylpyridine-4-chloropyridine-2‑carbonyl hydrazone (C₁₃H₁₁ClN₄O, HL) and its three water-soluble tetranuclear complexes [Cu₄(NO₃)₂(L)₄]·(NO₃)₂ (1), [Co₄(NO₃)₂(H₂O)(C₂H₅OH)(L)₄]·(NO₃)₂ (2) and [Zn₄(NO₃)₂(H₂O)(C₂H₅OH)(L)₄]·(NO₃)₂ (3) were synthesized and characterized showing that 1-3 were all tetranuclear complexes. The interactions of HL, 1-3 with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) were explored using ultraviolet-visible (UV-Vis) titration, fluorescence spectroscopy, microcalorimetry and molecular docking techniques. The UV-Vis spectroscopy measurements showed that complexes 1-3 could strongly bind to CT-DNA by the intercalation mode, while HL interacted with CT-DNA through groove binding. From the fluorescence spectroscopy results, the interaction between HL, 1-3 and BSA was a static quenching procedure, in which complexes 1-3 had two binding sites near Trp residues of BSA while HL only had one. The microcalorimetric studies revealed that the interactions of HL and 1-3 to CT-DNA/BSA were all endothermic and the duration of each interaction was all less than 30 min. The in silico molecular docking illustrated intermolecular interactions of 1-3 binding with DNA/BSA included hydrogen bond, halogen bond, hydrophobic and electrostatic interactions. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that complex 1 possessed better cytotoxicity against HeLa, A549, MCF7 and HCT-116 than cisplatin and could be used as an alternative anticancer drug.

{N'-[(E)-1-(5-Chloro-2-oxidophen-yl)ethyl-idene]-4-meth-oxy-benzohydrazidato-κ3 O,N',O'}(1H-imidazole-κN 3)nickel(II)

In the title complex, [Ni(C16H13ClN2O3)(C3H4N2)], the NiII ion is coordinated by two O atoms and one N atom derived from the dianionic N'-[(1E)-1-(5-chloro-2-hy-droxy-phen-yl)ethyl-idene]-4-meth-oxy-benzohydrazide ligand and one N atom from the imidazole mol-ecule. The N2O2 donor set defines an approximate square-planar geometry. The dihedral angles between the imidazole ring and the fused six-membered and meth-oxy-benzene rings are 17.78 (14) and 13.23 (16)°, respectively; the dihedral angle between the C6 rings is 6.63 (12)°. The most prominent feature of the mol-ecular packing is the formation of 41-helical chains (along the c axis) mediated by imidazole-N-H⋯O(phenoxide) hydrogen bonding; these are linked by methyl-C-H⋯Cl inter-actions.

Anions effect construction of 1D naphthalene diimide supramolecular chains by π interactions and fluorescence detect iodide anion

Five diverse 1D supramolecular chains, {[4-pmntd]}_n(1), {H₂[4-pmntd]•2Br^-}_n(2), {H₂[4-pmntd]•2NO₃^-}_n(3), {H₂[4-pmntd]•2ClO₄^-}_n(4), {H₂[4-pmntd]•2BF₄^-}_n(5), (where 4-pmntd was N,N'-bis (4-pyridylmethyl)naphthalene diimide) were synthesized and characterized by X-ray single-crystal structure analysis, IR spectroscopy, elemental analyses, thermogravimetric analyses, fluorescence detection. The anions effect construction of their 1D chain structural diversity through different π interactions. Compound 1 through the adjacent pyridine rings parallel π∙∙∙π interactions formed 1D linear chain structure. Compound 2 through Br^- anion∙∙∙π interactions and halogenbond interactions formed 1D zigzag chain structure. Compound 3 through lone pair∙∙∙π interactions of naphthalene diimide and the adjacent carboxyl group formed 1D stairway chain structure. Compound 4 through ClO₄^- anion∙∙∙π interactions formed 1D ribbon chain structure. Compound 5 through parallel π∙∙∙π interactions of the adjacent naphthalene diimide planes and pyridine rings formed 1D ladder chain structure. The five compounds' fluorescence properties and thermal stabilities were investigated. The compound 2 solution could fluorescence detection for iodide anion via fluorescence quenching.