Two new copper(II) binuclear complexes with 2-[(E)-(pyridine-2yl-hydrazono)methyl]phenol: Molecular structures, quantum chemical calculations, cryomagnetic properties and catalytic activity

Design, synthesis and characterization of novel Ni(II) and Cu(II) complexes as antivirus drug candidates against SARS-CoV-2 and HIV virus

This paper describes the structure-based design, synthesis and anti-virus effect of two new coordination complexes, a Ni(II) complex [Ni(L)2] (1) and a Cu(II) complex [Cu(L)2] (2) of (E)-N-phenyl-2-(thiophen-2-ylmethylene) hydrazine-1-carbothioamide(HL). The synthesized ligand was coordinated to metal ions through the bidentate-N, S donor atoms. The newly synthesized complexes were characterized by various spectroscopic and physiochemical methods, powdered XRD analysis and also X-ray crystallography study. Ni(II) complex [Ni(L)2](1) crystallize in orthorhombic crystal system with the space group Pbca with four molecules in the unit cell (a = 9.857(3) Å, b = 7.749(2) Å, c = 32.292(10) Å, α = 90°, β = 90°, γ = 90°, Z= 4) and reveals a distorted square planar geometry. A Hirshfeld surface and 2D fingerprint plot has been explored in the crystal structure of Ni(II) complex [Ni(L)2] (1). Energy framework computational analysia has also been explored. DFT based calculations have been performed on the Schiff base and its metal complexes to study the structure-property relationship. Furthermore, the molecular docking studies of the ligand and its metal complexes with SARS-CoV-2 virus (PDB ID: 7BZ5) and HIV-1 virus (PDB ID: 6MQA) are also investigated. The molecular docking calculations of the Ni(II) complex [Ni(L)2] (1) and a Cu(II) complex [Cu(L)2] (2) with SARS-CoV-2 virus revealed that the binding affinities at inhibition binding site of receptor protein are 9.7 kcal/mol and -9.3 kcal/mol, respectively. The molecular docking results showed that the binding affinities of Ni(II) complex (1) and Cu(II) complex (2) against SARS-CoV-2 virus were found comparatively higher than the HIV-1 virus (-8.5 kcal/mol and -8.2 kcal/mol, respectively). As potential drug candidates, Swiss-ADME predictions analyses are also studied and the results are compared with Chloroquine (CQ) and Hydroxychloroquine (HCQ) as anti-SARS-CoV-2 drugs.

New copper(II) μ-Alkoxo-μ-carboxylato double-bridged complexes as models for the active site of catechol oxidase: Synthesis, spectral characterization and DFT calculations

A series of four copper(II) μ-Alkoxo-μ-carboxylato double bridged complexes, [{Cu₂(L)}₂][(μ–O₂C–CO₂] 1, [{Cu₂(L)}₂(μ–O₂C–(CH₂)CO₂] 2, [{Cu₂(L)}₂(μ–O₂C–CH₂–CO₂] 3 and [{Cu₂(L)}₂(μ–O₂C–C₆H₄–CO₂] 4 (H₃L = 4-bromo-2-((E)-((3-(((E)-5-chloro-2-hydroxybenzylidene) amino)-2-hydroxypropyl) imino) methyl)-6-methoxyphenol and μ-dicarboxylate ions = oxalate, malonate, succinate and terephthalate) have been synthesized and characterized using several physicochemical techniques. The tridentate nature of H₃L is interpreted from IR spectra. The Epr spectra of these complexes are characteristic of the quintet state (S = 2) in central features and the triplet state (S = 1) of these tetranuclear complexes. The electrochemical potential of these complexes was investigated using CV (cyclic voltammetry) and DPV (differential pulse voltammetry). All complexes showed quasi reversible reduction peaks in the cathodic region. To explore the stability of these complexes, quantum chemical parameters like electronegativity, ionization potential, electron affinity, global hardness and softness, and electrophilicity were estimated and discussed. The synthesized complexes have been designed as structural and functional models of the catechol oxidase enzymes to investigate the catecholase activity. Additionally, superoxide dismutase activity data of all complexes have also been evaluated and compared with known SOD mimics.

N-((1H-Pyrrol-2-yl)methylene)-6-methoxypyridin-3-amine and Its Co(II) and Cu(II) Complexes as Antimicrobial Agents: Chemical Preparation, In Vitro Antimicrobial Evaluation, In Silico Analysis and Computational and Theoretical Chemistry Investigations

Researchers are interested in Schiff bases and their metal complexes because they offer a wide range of applications. The chemistry of Schiff bases of heterocompounds has got a lot of attention because of the metal's ability to coordinate with Schiff base ligands. In the current study, a new bidentate Schiff base ligand, N-((1H-pyrrol-2-yl)methylene)-6-methoxypyridin-3-amine (MPM) has been synthesized by condensing 6-methoxypyridine-3-amine with pyrrole-2-carbaldehyde. Further, MPM is used to prepare Cu(II) and Co(II) metal complexes. Analytical and spectroscopic techniques are used for the structural elucidation of the synthesized compounds. Both MPM and its metal complexes were screened against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Klebsiella pneumoniae species for antimicrobial studies. Furthermore, these compounds were subjected to in silico studies against bacterial proteins to comprehend their best non-bonded interactions. The results confirmed that the Schiff base ligand show considerably higher binding affinity with good hydrogen bonding and hydrophobic interactions against various tested microbial species. These results were complemented with a report of the Conceptual DFT global reactivity descriptors of the studied compounds together with their biological scores and their ADMET computed parameters.

Synthesis and characterization of novel copper(ii) complexes as potential drug candidates against SARS-CoV-2 main protease

Two novel copper(ii) Schiff base complexes, [Cu(L1)2] (1) and [Cu(L2)(CH3OH)(Cl)] (2) of [(Z)-(5-chloro-2-((3,5-dichloro-2-hydroxybenzylidene)amino)phenyl)(phenyl)methanone (L1H) and (Z)-(2((5-bromo-2-hydroxybenzylidene)amino-5-chlorophenyl)(phenyl)methanone)(L2H)], have been designed, synthesized and characterized.

Electronic investigation of the effect of substituents on the SOD mimic activity of copper (II) complexes with 8-hydroxyquinoline-derived ligands

Density functional theory (DFT) calculations were used to study the superoxide dismutase (SOD) mimic activity of two Cu²⁺ complexes with ligands derived from 8-hydroxyquinoline (8-HQ). Electron-donating and -withdrawing substituent groups were inserted into the structures to verify changes in the reactivity. The theoretical parameters obtained were compared and validated with the experimental data available. The results showed that the reduction process occurs with greater participation of the 8-HQ ligand and the oxidation step occurs with participation of the copper atom in the complexes, where the electron received during the reduction step is used to reduce the Cu²⁺ to Cu⁺. The calculated electronic affinity showed good correlation with the experimental mimetic activity, and the analysis of this property, of total charge and of molecular orbitals indicated an increase in the mimetic activity with the insertion of electron-withdrawing substituent groups in the structures.