Structural, magnetic and spectroscopic characterization of two unusual end-on bis(μ-acetato/μ-nitrato) bridged copper(II) complexes with N′-[phenyl(pyridin-2-yl)methylidene]furan-2-carbohydrazide and (2E,4Z)-N,2-dimethylhepta-2,4,6-trienamide-1-phenyl-1-pyridin-2-ylmethanimine (1:1) as capping ligands

In silico drug encapsulation using 2-hydroxypropyl-β-CD, tyrosine kinase and tyrosinase inhibition of dinuclear Cu(II) carboxylate complexes

In recent years, copper carboxylate complexes have garnered significant interest for biological applications. This study focuses on 20 Cu(II) carboxylate complexes selected from our previous research. Due to the hydrophobic nature of these complexes, the 2-hydroxypropyl-β-cyclodextrin (2HPβCD) was employed as a carrier to reduce toxicity and increase solubility for controlling drug delivery. Monte Carlo calculations were performed to confirm the interaction between the optimized structures of Cu(II) complexes and 2HPβCD, forming a host-guest system. All the structures were simulated and optimized using DFT-D calculations in Material Studio 2017. The results indicated that a neutral medium is more favorable for the adsorption of these complexes into 2HPβCD. More negative binding energy values suggested strong and energetically favorable adsorption on 2HPβCD. Complexes 4, 5, and 7 exhibited the highest interaction, making them excellent candidates for drug delivery systems. DFT-D calculations were also used to investigate the release of complexes, revealing that complexes 5, 14, and 19 were difficult to release due to their lowest energy. In contrast, complexes 8, 9, and 16 were found to be most efficient to release due to weak non-covalent interactions with 2HPβCD as we can predict from binding energy obtained by DFT-D. No specific trend was observed in the interaction of the complexes with 2HPβCD. Additionally, the effects of these complexes on c-kit tyrosine kinase and Mushroom tyrosinase were studied by molecular docking. The results demonstrated that all the complexes interacted with the active site of respective receptors through hydrophobic interactions. Complexes containing 1,10-phenanthroline and 2,2-bipyrdine were identified as having a strong, spontaneous binding ability with receptors.

Designing and Exploration of the Biological Potentials of Novel Centrosymmetric Heteroleptic Copper(II) Carboxylates

Copper(II) complexes with a general formula [Cu2(3,4-F2C6H3CH2COO)4(L)2], where L = 2-methylpyridine (1) and 3-methylpyridine (2), are reported here. The FTIR spectra of the complexes confirmed the bridging bidentate coordination mode of the carboxylate ligand. The low (475 and 449 cm-1) and strong (727 & 725 cm-1) intensity bands in the FTIR spectra, due to Cu-N stretches and pyridyl ring vibrations, confirmed coordination of the 2-/3-methyl pyridine co-ligands in complexes 1 and 2, respectively. A binuclear paddlewheel structural arrangement with a square pyramidal geometry was confirmed for copper atoms in the complexes via single-crystal X-ray analysis. The DPPH, •OH radical, and α-amylase enzyme inhibition assays showed higher activities for the complexes than for the free ligand acid. The binding constant (Kb = 1.32 × 105 for 1 and 5.33 × 105 for 2) calculated via UV-VIS absorption measurements and docking scores (-6.59 for 1 and -7.43 for 2) calculated via molecular docking showed higher SS-DNA binding potential for 2 compared to 1. Viscosity measurement also reflected higher DNA binding ability for 2 than 1. Both complexes 1 and 2 (docking scores of -7.43 and -6.95, respectively) were found to be more active inhibitors than the free ligand acid (docking score of -5.5159) against the target α-amylase protein. This in silico study has shown that the herein reported compounds follow the rules of drug-likeness and exhibit good potential for bioavailability.

Use of a Metallic Complex Derived from Curcuma Longa as Green Corrosion Inhibitor for Carbon Steel in Sulfuric Acid

A tin-containing metallic complex derived from Curcuma longa, bis[1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dionato-κO,κO ${}^{\prime }$ ]bis(butyl), has been obtained and used as a green corrosion inhibitor for carbon steel in 0.5 M sulfuric acid by using weight loss, electrochemical techniques, and the Density Functional Theory. It was found that the obtained metallic complex greatly decreases the steel corrosion rate by adsorption according to a Frumkin model in a weak, physical type of adsorption. Inhibitor efficiency increased with its concentration, and it acted as a mixed type of inhibitor. Results were supported by quantum-chemical research in order to examine the relationship between structural and electronic properties and the inhibitor efficiency.

Neutral 4-phenyl-1-[phenyl(pyridin-2-yl)methylidene]semicarbazide and its salt forms with inorganic anions

Semicarbazones can exist in two tautomeric forms. In the solid state, they are found in the keto form. This work presents the synthesis, structures and spectroscopic characterization (IR and NMR spectroscopy) of four such compounds, namely the neutral molecule 4-phenyl-1-[phenyl(pyridin-2-yl)methylidene]semicarbazide, C₁₉H₁₆N₄O, (I), abbreviated as HBzPyS, and three different hydrated salts, namely the chloride dihydrate, C₁₉H₁₇N₄O⁺·Cl^-·2H₂O, (II), the nitrate dihydrate, C₁₉H₁₇N₄O⁺·NO₃^-·2H₂O, (III), and the thiocyanate 2.5-hydrate, C₁₉H₁₇N₄O⁺·SCN^-·2.5H₂O, (IV), of 2-[phenyl({[(phenylcarbamoyl)amino]imino})methyl]pyridinium, abbreviated as [H₂BzPyS]⁺·X^-·nH₂O, with X = Cl^- and n = 2 for (II), X = NO₃^- and n = 2 for (III), and X = SCN^- and n = 2.5 for (IV), showing the influence of the anionic form in the intermolecular interactions. Water molecules and counter-ions (chloride or nitrate) are involved in the formation of a two-dimensional arrangement by the establishment of hydrogen bonds with the N-H groups of the cation, stabilizing the E isomers in the solid state. The neutral HBzPyS molecule crystallized as the E isomer due to the existence of weak π-π interactions between pairs of molecules. The calculated IR spectrum of the hydrated [H₂BzPyS]⁺ cation is in good agreement with the experimental results.

Varying structural motifs, unusual X-band electron paramagnetic spectra, DFT studies and superoxide dismutase enzymatic activity of copper(ii) complexes with N′-[(E)-phenyl(pyridin-2-yl)methylidene]benzohydrazide

A diverse set of new copper(ii) complexes synthesized as possible models for antioxidant superoxide dismutase mimics.

Unprecedented tetranuclear complexes with “weighing balance shaped” topology: single crystal structures, unusual EPR spectra, magnetic properties and antioxidant activity

Two new copper(ii) complexes have been synthesized and characterized by single crystal X-ray diffraction.

Unprecedented copper(ii) mediated in situ formation of gem-diol binuclear complexes: a combined experimental and computational study

The two alkoxo bridged complexes [Cu₂(L¹)₂(HL²)₂(H₂O)](NO₃)₂·2H₂O 1 and [Cu₂(L¹)₂(HL²)₂](NO₃)₂·H₂O 2 have been synthesized by metal assisted hydrolysis with two Schiff bases, where L¹ is 2-benzoylpyridine and HL² is phenyl(pyridin-2-yl)methanediol.

Synthesis, structure, magnetic properties and EPR spectroscopy of a copper(ii) coordination polymer with a ditopic hydrazone ligand and acetate bridges

The synthesis, structure, EPR spectroscopy and magnetic properties of a 1D coordination polymer of Cu(ii) containing two kinds of acetate bridged dimers is reported.