Mixed-metal Complexes Research Articles

Synthesis, Characterization and Antimicrobial Activity of Mixed Antibiotic-Vitamin Metal Complexes Involving Metronidazole and Vitamin B1 (Thiamine)

Antimicrobial resistance (AMR) poses a critical threat to global health, making it imperative to develop novel therapeutic strategies. This study focuses on the synthesis and characterization of mixed antibiotic-vitamin metal complexes involving metronidazole and vitamin B1. Metal complexes, known for their unique structural properties, were synthesized with Nickel, Zinc, and Iron salts to enhance the biological efficacy of the parent antibiotics. These complexes were analyzed using various physicochemical methods, including ultraviolet-visible and infrared spectroscopy, and were evaluated for their solubility, elemental composition, and melting points. The antimicrobial activity of the synthesized complexes was tested against bacterial strains such as Streptococcus feacalis, Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus, as well as fungal strains like Aspergillus niger and Candida albicans. The results demonstrated that the metal complexes exhibited enhanced antibacterial and antifungal properties compared to the free ligands. Specifically, the zinc and nickel complexes showed significant inhibition against Klebsiella pneumoniae and Aspergillus niger, respectively. This study highlights the potential of metal complexes as promising agents to combat AMR, providing a foundation for future research into drug development and clinical applications.

Single and mixed dithiocarbamato metal(III) complexes (Co, Rh, and Ir): Crystal and molecular structure description and interplay

This review focuses on the crystal and molecular structures of single and mixed dithiocarbamate ligands of cobalt, rhodium, and iridium in the +3 oxidation state. The complexities of their chelating and bridging modes come into play through modification of the substituents on the carbamate nitrogen atoms of the ligands and additional coordination of secondary phosphino-containing ligands, culminating in various applications such as biological, analytical, medicine, and catalysis. Other considerations include the geometrical coordination environments around the metal centres and their comparison with isostructural congeners. The distortions around the metal centres and their subsequent effects on the symmetries of bonds in the primary and secondary coordination spheres are discussed. The trans-effects of secondary P-ligands and their effects on geometrical alignment and structural stability have become valuable yardsticks in analyzing structural modifications and stabilities.

Synthesis and Structural Study on the Cd(II)-Gd(III) Mixed-Metal Complex Based on 2,6-pyridinedicarbonyl bis(N,N-diethylthiourea)

The mixed-metal complex with the composition of [GdCd2(L)3](PF6) (H2L = 2,6-pyridinedicarbonyl bis(N,N-diethylthiourea) has been synthesized by the ‘one-pot’ reaction of GdCl3∙6H2O, Cd(CH3OO)2∙2H2O and H2L with 1 : 2 : 3 molar ratio in methanolic solution. The structure of the obtained complex is characterized by IR spectroscopy, mass spectrometry and single-crystal X-ray diffraction. The results reveal a cationic trinuclear mixed-metal complex composed of one Gd(III) cation, two Cd(II) cations and three dianionic ligands {L2–}. The charge of the complex is compensated by a PF6– anion.

Synthesis, Characterization and Antimicrobial Analysis of Nickel and Cobalt Complexes of Condensates of Salicylaldehyde and 2-Hydroxy Aniline

This study on the synthesis, characterization and antimicrobial analysis of Nickel and Cobalt complexes of condensates of salicylaldehyde and 2-hydroxy aniline constitutes an attempt towards the development of new molecular compounds that could destroy the barrier of resistance of pharmaceutical products. The ligands of 2-phenyliminomethylphenol (PMP) and 2,2-hydroxy benzylidene aminophenol (HAP) were first prepared by separately reacting Aniline with Salicylaldehyde on the one hand, and 2-aminophenol with Salicylaldehyde on the other hand. The unmixed metal complexes were prepared by reacting either of 0.29 mmol 2-phenylimino methyl phenol ligand with the metal salt or 0.29 mmol 2,2-hydroxybenzylideneaminophenol ligand with the metal salt while the mixed metal complexes were prepared by addition of equimolar amount of ligands of 2-phenyliminomethylphenol and 2,2-hydroxybenzylideneaminophenol into the metal salt. The molecular structures of the ligands and their complexes have been determined and characterized using GC-MS, FTIR, UV-Vis, 1H-NMR, and X-ray diffraction techniques. The melting point and solubility of the ligands and synthesized complexes were equally determined. Antimicrobial studies were carried out with ligands PMP and HAP and the metal complexes using clinical isolates of Gram Positive Bacteria (Staphylococcus aureus and Bacillus substilis), Gram Negative Bacteria (Escherichia coli and Pseudomonas aeruginosa) and Fungi (Candida albicans and Aspergillus niger). All complexes and ligands were found to be soluble in dimethylsulfoxide (DMSO). Asymmetric Octahedral geometry is observed for Nickel (II) and Cobalt (II) complexes with PMP, HAP, and the mixed ligands. A bidentate ligand is coordinated to metal ions through oxygen atoms of carbonyl groups and nitrogen atoms of two imine groups for Nickel (II) and Cobalt (II) complexes. The findings from the XRD pattern indicate that the ligand and metal complexes are crystalline with a high crystallite size of 119.23nm to 638.67nm. The FTIR spectra for 2-phenyliminomethylphenol (PMP) showed IR absorption band at 1569.2 cm-1 suggesting the stretching vibration of the C=C bond in the benzene rings, while the bands at 1613.9 cm-1 indicated the =C-N stretching in the benzene ring. The complexes showed electronic spectra which suggest that energy was absorbed in the ultraviolet/visible region, producing changes in the electronic energy of the compound and resulting from the transition of valence electrons in the complexes. The XRD findings reveal that the crystal formed by the ligands and their respective complexes are large. The ligands were found to be larger in size than the complexes and this could be due to the complexation reactions. The X-ray diffractograms of the metal complexes produced good intense peaks that suggest high crystallinity. The ligand of 2-phenyliminomethylphenol (PMP) and 2,2-hydroxy benzylidene aminophenol (HAP) showed partial inhibitory action on the clinical isolates of Gram Postive, Gram Negative and zero inhibitory effect on the fungi while the divalent metal complexes of both mixed and unmixed ligands exhibited either stronger or strongest inhibition. The study concludes that the synthesized ligands and their metal complexes are purely crystalline as revealed by the chemical analysis, exhibited inhibitory actions on Gram Positive, Gram Negative and fungi species.

Exploring the anticancer activity of 1-(2-methyl-3-furoyl)-4-phenyl-3-thiosemicarbazide and its Mn(II) complex: Synthesis, spectral, crystal structures, and Hirshfeld surface analysis

The chemistry of mixed ligand transition metal complexes has been of interest of researchers owing to its diverse application and bonding features. Herein, a new thiosemicarbazide derivative namely 1-(2-methyl-3-furoyl)-4-phenyl-3-thiosemicarbazide (HmfpTSC) has been synthesized along with its [Mn(mfpTSC)2(o-phen)] (C1) complex. The prepared ligand (HmfpTSC) and the complex have been confirmed via spectroscopic and single-crystal X-ray data. The HmfpTSC and complex crystallize in a monoclinic crystal system with space group P21/c and P21/n, respectively. HmfpTSC behaves as a uninegative bidentate ligand and its two-unit binds with metal ion along with one unit of o-phen. Using Hirshfeld surface analysis, the weak interactions seen in HmfpTSC and complex have been quantitatively investigated. The MTT assay was used to assess the cytotoxicity of HmfpTSC and [Mn(mfpTSC)2(o-phen)] complex against Dalton's lymphoma cells. Further, the mechanism of anticancer action of ligand and complex was investigated through DAPI, AO/EB staining, and flow cytometry. The both AO/EB and DAPI staining provided compelling evidence of complex-induced cellular and nuclear changes consistent with apoptosis and necrosis.

Metal complexes with thiosemicarbazone derivative and isatine: A promising new class of materials for biomedical and environmental applications

Metal complexes with thiosemicarbazones and isatine have been shown to exhibit a wide range of biological activities, including antibacterial, antifungal, and anticancer activity. These complexes have also been shown to be effective photocatalysts for degrading dyes, making them a subject of significant interest. This article presents the synthesis and characterization of mixed ligand complexes of isatine-thiosemicarbazones to explore their biological activity and potential for photocatalytic applications. In this study, we synthesized mixed ligand complexes of isatine-thiosemicarbazones with various metal ions, including Cu(II), Cd(II), and Fe(III). Characterization techniques such as elemental analysis, infrared (IR), mass spectrometry (MS), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) were utilized to understand their structural composition and morphological properties. The complexes exhibited remarkable antibacterial activity against Escherichia coli, Staphylococcus aureus, Streptococcus mutants, and antifungal effects on Candida albicans. Notably, the Fe-complex demonstrated the highest activity, followed by the Cu-complex and Cd-complex. Strong anticancer effects were observed against human liver HepG2 and breast MDA cancer cells, with the Fe-complex displaying the highest activity. Additionally, the complexes displayed significant photocatalytic activity in the decomposition of rose bengal dye using ultraviolet light irradiation, with the Cu-complex showing the highest degradation efficiency. The results indicate that these mixed ligand metal complexes have potential therapeutic applications as antibacterial, antifungal, and anticancer agents. Moreover, they suggest their prospective utility as photocatalysts for the remediation of dye-contaminated wastewater.

Exploring the versatility of sulfur-containing heterocyclic metal complexes: Application in medical and prospects of visible-light-driven photocatalysis

Numerous heterocyclic moieties serve as the foundational structure for clinically employed drugs, underscoring the significance of heterocycles in the innovation of pharmacologically active compounds. In the present investigation, a heterocyclic skeleton of thiophene-clubbed benzimidazole (tmb) was developed and utilized to synthesize seven novel series of metal (M(II) = Co, Ni, Cu, and Zn) complexes to explore diverse applications including pharmacological and photocatalytic performance. A sharp singlet peak appeared at 5.72 ppm (tmb) and 5.94 ppm for the Zn(II)-tmb complex corresponding to -CH2 protons, as evidenced by 1H NMR results, confirming the formation of targeted compounds. Antimicrobial assay and docking studies confirmed that the mixed metal complex; [Cu(tmb)2(1,10-phen)Cl2] possesses the highest activity and displayed significant biofilm inhibition, achieving 86.35 and 89.8% at concentrations of 1 and 0.020 mg/mL, respectively against E. coli. Furthermore, the photocatalytic activity was monitored by the degradation of methylene blue dye under direct sunlight and [Cu(tmb)2Cl2] exhibited a maximum degradation efficiency of 96.15% in 45 min. These findings could serve as inspiration for the development of benzimidazole-based metal complexes as effective anti-biofilm and photocatalytic agents.

Mixed ligand 4‑hydroxy acetanilide-febuxostat complexes of Co(II),- Ni(II), Cu(II) and Zr(IV): Synthesis, structural characterization, DFT calculations, antibacterial, antioxidant and molecular docking studies

The synthesized mixed ligand metal complexes were achieved by a combination of febuxostat (2-(3-cyano-4-isobutyloxyphenyl)-4-methyl-5-thiazolecarboxylic acid) (FEB) and paracetamol (4‑hydroxy acetanilide) (Para) together with crucial biologically relevant elements. These elements, including Co(II), Cu(II), Zr(IV), and Ni(II) chlorides, play important roles in various biological systems and mechanisms, such as antioxidant, antimicrobial systems, and contribute to diverse functions and structures. To identify chemical formulae and structures of synthesized complexes, physical-analytical, spectroscopic (XRD, FT-IR, ESR, 13C NMR, 1H NMR, and UV-visible), mass spectrometry (MS), TG-DTG studies were used and supported by computational approaches. FT-IR and 1H NMR data revealed that FEB chelated through sulfur of thiazole ring as a mono-negative bidentate type and deprotonated oxygen of carboxylate group, according to lack of characteristic band at 1677 cm−1 and signal at δ = 13.37 ppm (-OHCOOH), whereas Para chelated through nitrogen and oxygen of amide group as a neutral bidentate ligand. Magnetic moment and electronic spectra data revealed that complexes have an octahedral structure. The optical band gap (Eg) for our compounds was calculated and according to Eg values, all complexes were semi-conductors and fell into the class of solar materials compared with FEB and Para. XRD pattern showed the monoclinic polycrystalline structure for all compounds except the Zr(IV) complex was amorphous. Kinetic parameters of the thermal decomposition stages were calculated. DFT was utilized to confirm bonding mode for FEB and Para with metal ions and according to calculations of energy band gap (ΔE) of complexes, Cu(II) complex with smaller ΔE is more reactive but, Zr(IV) complex with higher ΔE is less reactive than FEB and Para. The antibacterial activity of FEB, Para, and their complexes were tested against two G-ve and three G+ve bacteria. Co(II) complex displayed remarkable effectiveness and high significance against all strains of bacteria, compared with other compounds tested. All compounds demonstrated antioxidant effects, Cu(II) and Zr(IV) show greater antioxidants than parent ligands with IC50 values 0.040 and 0.057 mg/mL. The binding pattern and active site of all compounds were put through molecular docking studies and compared with empirical biological data.

Non-covalent interactions orchestrated distinct molecular arrangements along different axes within the novel mixed ligand thorium metal complex: Experimental and theoretical insights

This study presents the crystallographic analysis of a defect-free single crystal of a novel thorium metal complex, revealing its intricate three-dimensional molecular structure. The crystal was found to belong to space group C2/c, containing six mononuclear complexes in each unit cell. The central metal atom exhibited a ten-coordinated distorted sphenocoronal capped square antiprismatic geometry, forming bidendate bonds with 4,4,4-trifluoro-1-(thiophen-2-yl)butane-1,3‑dione) (TFTBD) and a 1,10 phenanthrene (Phe) ligand groups. Intriguingly, the crystal displayed a nonplanar geometry and featured various non-covalent interactions within its structure, both intra and intermolecular, enhancing its overall stability. Notably, intramolecular interactions involving CH⋯F/S/O bonds led to the formation of unique synthons, further substantiated by NCI analysis. Intermolecular interactions, such as CH⋯F, CH⋯Cg, and π⋯π interactions, played a crucial role in the crystal packing, resulting in the formation of two-dimensional molecular zig-zag chains, linear layers and hexagonal arrangements on the crystallographic ab-, bc-, and ca-planes respectively.

Chromophore appended DPA-based copper(II) complexes with a diimine motif towards DNA binding and fragmentation studies.

Mixed ligand copper(II) complexes [Cu(L1)(bpy)](ClO4)21 and [Cu(L2)(bpy)](ClO4)22 (where L1 = 1-(anthracen-9-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine, L2 = 1-(pyren-1-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine and bpy = 2,2'-bipyridine) were synthesised and characterised thoroughly via different analytical and spectroscopic techniques i.e., UV-vis spectroscopy, fluorescence spectroscopy, FT-IR spectroscopy, HRMS and EPR spectroscopy. The molecular structures of the synthesised complexes were obtained using the single-crystal X-ray diffraction technique. Both complexes exhibited penta-coordinated and acquired distorted square pyramidal geometry. The redox behaviour of complexes 1 and 2 was investigated by employing cyclic voltammetry. The DNA binding study was carried out by UV-vis spectrophotometry using double-stranded salmon sperm DNA (ds-ss-DNA). The binding constant (Kb) values of 1 and 2 were 0.11 × 104 M-1 and 1.05 × 104 M-1, respectively, which indicates that 2 has better binding ability than 1. This might be due to the higher conjugative abilities with the extended surface area of the aromatic pyrene ring compared to the anthracene moiety. The fluorescence quenching experiments were also performed with EB bound DNA (EB-DNA) and Stern-Volmer constant (KSV) values were calculated as 1.23 × 105 M-1 and 1.39 × 105 M-1 for 1 and 2, respectively, suggesting that 2 showed stronger interaction with ss-DNA than 1. The molecular docking data support the DNA-binding studies, with the sites and mode of interactions against B-DNA varying with 1 and 2. Evaluation of the DNA binding properties of the complexes to linearized plasmid DNA indicated that 2 had modest DNA binding properties, which is a pre-requisite for a genotoxic agent. The effect of 1 and 2 on cell survival was analysed using HeLa cells by MTT assay and it was observed that the IC50 values of 1 and 2 were 43.7 μM and 18.6 μM, respectively. Our study paves the way for the designing of bio-inspired novel mixed metal complexes, which shows promising results for further exploration of molecular and mechanistic studies towards the development of non-platinum based economical metallodrugs.

Novel terephthalaldehyde bis(thiosemicarbazone) Schiff base ligand and its transition metal complexes as antibacterial Agents: Synthesis, characterization and biological investigations

The synthesis and structural characterization of mixed ligand metal complexes from terephthalaldehyde bis(thiosemicarbazone) (TPTSC) (L1) and alanine (L2) by using ultrasonication are reported. The ligand and their transition metal complexes were characterized on the basis of their elemental, FT-IR, magnetic moment, molar conductance, mass spectra, and SEM analysis. The mixed ligand complexes are in the ratio 2:1:2 [M:L1:L2] ratio as found from the elemental analyses and found to have the formulae [M2L1(L2)2].nH2O where M = Co(II), Ni(II), Cu(II), Cd(II) and Zn(II), L1 = TPTSC and L2 = alanine. The molar conductance data show that complexes are non-electrolytes. FT-IR spectra show that the Schiff base is coordinated to the metal ions in a bidentate manner with N and S donor sites of the terephthalaldehyde bis(thiosemicarbazone) and second ligand alanine coordinated to the metal ions via its N and O of amino acid. The geometrical structure of these complexes is found to be tetrahedral. The antimicrobial activity of the synthesized Schiff base ligand and mixed-ligand metal complexes have been screened against gram-positive and gram-negative bacteria and two fungi species were tested. Mixed ligand complexes exhibited significant antibacterial activity against Klebsiella Pneumoniae, Salmonella typhi, Enterococcus Faecalis, Staphylococcus aureus, Escherichia coli and the fungi Aspergillus flavus and Aspergillus niger. Further, these compounds have been screened for their anticancer activity using Human Breast Cancer Cell Line MDA-MB-231.

Synthesis, characterization and <i>In-silico</i> study of anti-cancer potential of Cu(II) and Ni(II) complexes of (E)-2- benzylidenehydrazinecarboxamide

In this study, (E)-2-benzylidenehydrazinecarboxamide coordination compounds and mixed ligand metal complexes with oxalic acid or 1,2-diaminocyclohexane were synthesized. Their potential cytotoxic effects and interactions with B-DNA evaluated. This was with a view to demonstrate their potential as anticancer agents for breast cancer. (E)-2-Benzylidenehydrazinecarboxamide (benzaldehyde semicarbazone) coordination compounds of Cu(II) and Ni(II) and mixed ligand metal complexes with oxalic acid and 1,2- diaminocyclohexane were synthesized. The resultant complexes were characterized by physicochemical techniques including melting point measurement, percent metal analysis, solubility, and magnetic susceptibility measurements. Electronic and Fourier transform infrared (FTIR) spectroscopy, were performed to further lucidate the structures of the complexes. The synthesized compounds were examined for their cytotoxic effects and DNA interactions with B-DNA. The results obtained showed that all the ligands used were bidentate ligands. They bound to the metal ions through oxygen and nitrogen atoms. All synthesized compounds showed good cytotoxic activity against brine shrimp nauplii except for the (E)-2-benzylidenehydrazinecarboxamide copper(II) complex. All of the metal complexes, with the exception of the (E)-2- enzylidenehydrazinecarboxamide coordination copper complex, bound to DNA with moderate binding energies. They favoured conventional hydrogen bonding and hydrophobic interaction mostly. The copper complex with 1,2-diaminocyclohexane had the most interaction and a good binding effect to the DNA and better than oxaliplatin, the standard used. This therefore indicated the potential of these compounds as probable chemotherapeutic agents against breast cancer cells.

Antibacterial, antifungal, DNA interactions, and antioxidant evaluation of Cu(II) Co(II), Ni(II), Mn(II) and UO2(II) mixed ligand metal complexes: Synthesis, characterization and molecular docking studies

The current work was designed to prepare novel 1:1:1 Metal (M): primary ligand (HL1): co-ligand (HL2) complexes; [Cu(L1)(L2)(OH2)2] (1), [Co(L1)(L2)]H2O (2), [Ni(L1)(L2)(OH2)2] 0·.75H2O (3) and [Mn(L1)(L2)(OH2)2] 4·.5H2O (4) and [UO2(L1)(L2)] (5) from ligands 7-Formyl-8-hydroxyquinoline (oxine) (HL1), 2-aminophenol (HL2) and characterized by analytical and spectroscopic techniques. FTIR, mass spectra, ESR techniques, elemental analysis, and thermal analysis were used to characterize the newly formed complexes. The results of the elemental analysis show the formation of [HL1:M:HL2] complexes. The ligands act as a mononegative bidentate chelating agent coordinating through C = O, NH2 and two OH groups by replacement of a proton from the latter groups. The molecular docking between the protein receptors and the ligand (HL1), ligand (HL2) and its mixed ligand metal complexes (1–5) was studied. The interface between HL2, complexes and calf thymus DNA (CT-DNA) displays hypochromism behavior. The binding value constant (Kb) are calculated and found to be 5.29 × 103, 8.49 × 104, 2.45 × 105, 2.96 × 104 and 1.16 × 104, 3.08 × 104 M−1 for HL2 and its mixed ligand metal complexes (1–5), respectively. Antimicrobial properties of ligands and the synthesized complexes were also screened versus G + ve bacteria (S. aureus and B. cereus), G-ve bacteria (K. pneumoniae, Pseudomonas sp. and E. coli, and fungi (F. oxysporum, A. niger, and C. albicans). The obtained results revealed the strong antimicrobial action of metal complexes with MIC, MBC and MFC values ranging from 5 to 45 µg/ml. HL1 showed higher antimicrobial and antioxidant activities than HL2 and major of the prepared metal complexes. All metal mixed ligand complexes inhibited the multidrug-resistant bacterium; Klebsiella pneumoniae compared to the standard antibiotic, penicillin G. Also, all metal mixed ligand complexes showed potent antifungal activities against both Aspergillus niger and Candida albicans.

Synthesis, Characterization, DNA Synergy and Molecular Docking Studies of Novel 1,10-Phenanthroline Derived Mixed Ligand Metal(II) Complexes

The effect of tumour and all its related costs, both human and commercial factor is driving the exploration for novel curative medicines.Although platinum-based anticancer drugs have shown considerable success, their use is complicated by a number of drawbacks. Therefore, this study is mainly designed for transition metal complex based chemotherapeutic agents to reduce the obstacles for platinum-based anticancer agents presently used. Herein, novel mixed ligand-metal(II) complexes derived from 9-anthraldehyde, 2-aminophenol, metal chlorides and 1,10-phenanthroline (co-ligand) were synthesized and characterized using several spectral techniques, which revealed that they possess an octahedral structure. The interaction of calf thymus DNA (CT-DNA) with synthesized compounds confirmed that the compounds are binded with DNA via intercalation. The mode of interaction was affirmed by the docking simulations, where the synthesized compounds were docked with EGFR protein and 1B-DNA through intercalation. The biological screening results revealed that the synthesized complexes exhibited superior anti-pathogenic screening properties compared to ligands. The proliferation resistance against cancer cells and free radical scavenger studies of prepared compounds indicated that the presence of heterocyclic ligand is an important factor for boosting the anticancer potential and radical scavenger skill.

Moxifloxacin and hydrazine mix ligand metal complexes of Cd(II), Cu(II), Co(II), and Zn(II); synthesis, characterization, and pharmacological activities, with molecular docking studies

In the current study, four new mixed ligand metal complexes of Cd(II), Cu(II), Co(II), and Zn(II) with moxifloxacin (used as a primary ligand) and hydrazine (as an ancillary ligand) were synthesized. The newly prepared organometallic compounds were characterized by using conventional spectroscopic (UV–Vis, Atomic absorption, FTIR, and powder XRD), microscopic (SEM), elemental (CHN), and thermal (TGA) techniques. The synthesized chelates were evaluated for cytotoxicity (by hemolytic activity) and antimicrobial activity against different bacterial (S. aureus, B. subtilis, E. coli, and P. multocidia) and viral (A. flavus, A. niger, R. solani, and A. alternata) strains. The prepared metal complexes were also in vitro assayed for antidiabetic potential through α-amylase inhibition assay, and the results were further verified through molecular docking studies. This study demonstrates that half of the new metal complexes are good antibacterial agents, and complex 2 was significantly active against all four assayed bacterial strains. All the synthesized mixed ligand metal complexes proved to have significant fungicidal activity. Complex 3 has proved to be potentially active (24.3%) against Aspergillus flavus with a higher activity as compared to the reference standard, i.e., fluconazole (23.5%). The hemolytic values of 6.07%, 4.94%, and 12.05% for metal complexes 2, 3, and 4, respectively, were in acceptable range and comparable to moxifloxacin, while higher (19.05%) for complex 1. Present work reveals that all the bi-ligand complexes are significant antidiabetic agents, where complexes 3 and 4, with 62.45% and 54.25% α-amylase inhibition, have a similar effect as that of the standard drug, i.e., Acarbose having 64.12% α-amylase inhibition. The molecular docking studies correspondingly prove these two compounds as potent α-amylase inhibitors.

Synthesis, computational drug likeness, DFT studies and in vitro biological activity evaluation of some heteronuclear complexes of functionalized (E)‐2‐(butan‐2‐ylidene) hydrazinecarbothioamide ligand

AbstractThe dinuclear complexes of Schiff bases possess interesting structures and activity spectrum. Five mixed metal complexes of 2‐butanone thiosemicarbazone were prepared and characterized by different spectroscopic techniques. Molecular docking studies were done with the selected proteins. Computational drug likeness prediction was done using automated softwares. Toxicity assessment and Principal Component Analysis (PCA) was done by OSIRIS 4.6.1 and used to assess the toxicity whereas bioactivity scores and physicochemical properties were predicted by Molinspiration 2016.03. Principal Component Analysis (PCA) was performed using Osiris Property Explorer 4.5.1. Molecular docking studies were performed with three proteins. The anticancer activity was tested against MCF‐7, A549 and HepG‐2 cell lines whereas antibacterial activity was tested against two bacterial strains. The melting points of the complexes were >350oC, indicating high thermal stability. Cu‐Zn‐containing complex showed the least binding energy against the three proteins. The bioactivity scores of the complexes were between ‐0.50 and 0.0. Against A549 Cu‐Zn, Co‐Zn and Fe‐Zn containing complexes showed potential activity. Against MCF‐7, Fe‐Cu containing complex had IC50 of 53.5 whereas Co‐Zn containing complex was active against HepG2. Three complexes were active against S. aureus in the tested range. The dinuclear complexes showed potential biological activity as compared to the mononuclear complexes.

Synthesis of some new nanoparticles mixed metal complexes of febuxostat in presence of 2,2′-bipyridine: Characterization, DFT, antioxidant and molecular docking activities

New Mn(II), Fe(III), Co(II), and Ni(II) complexes with urate lowing drug febuxostat (FEB) and 2,2′-bipyridine (Bipy) were designed and depicted. Elemental analysis, molar conductance, magnetic measurements, FT-IR, UV–visible, 1H NMR, mass spectrometry (MS), X-ray diffraction (XRD) and thermal analyses (TG-DTG) studies were used to depict complexes. The FT-IR data revealed that the FEB and Bipy have two donating sites, the oxygen of the carboxylate group and the sulfur atom of the thiazole ring in FEB while, Bipy has two nitrogens of the pyridyl ring. Based on information from the magnetic and electronic spectra, an octahedral geometry was suggested for complexes. The nature of the water molecules and their thermal stability were investigated using TG-DTG analyses. By Coats-Redfern equations determined thermodynamic properties in addition to Horowitz-Metzger equations. The purpose XRD examination of compounds was used to determine the compounds (crystalline or amorphous), average crystallite size (Cs) and Crystallographic data. The bond angles, bond lengths, dipole moment, total energy and equilibrium geometry of metal complexes were investigated by DFT calculations. FEB exhibited an antioxidant action in addition to its metal complexes, with IC50 values of 0.124, 0.316, 0.635, 0.186 and 2.234 mg/mL for FEB, Mn(II), Fe(III), Co(II) and Ni(II) compounds, respectively. The molecular docking data demonstrated that the complexes have competent stabilizing scores of −6.66, −6.50, −7.18 and −7.59 kcal/mol, respectively. The data of Co(II) complex revealed the most promising potential xanthine oxidase inhibitory activity.

Characterization, DFT calculations and antimicrobial assays of some novel nanoparticles mixed ligand complexes of 5-cyano-6-phenyl-2-thiouracil in presence of 1,10-phenanthroline

Some trivalent (Cr(III), Fe(III)) and divalent (Co(II), Ni(II), Cu(II) Zn(II)) combined with synthesized 5-cyano-6-phenyl-2-thiouracil (H2CPT) in presence 1,10-phenanthroline monohydrate (Phen) to produce crystalline and semi-crystalline nanoparticles mixed ligand metal complexes. The separated nanoparticles complexes were investigated by physicochemical, spectroscopic techniques (FT-IR, UV–Vis. and 1H NMR), X-ray powder diffraction (XRD) and thermal analyses (TG-DTG-DTA). The metal complexes were ionic with 1:2 electrolytes for divalent elements and 1:3 electrolytes for trivalent elements. The FT-IR spectra indicated that H2CPT and Phen functioning as bidentate ligand binding to the metal ions via oxygen and nitrogen of cyano group of H2CPT and through two nitrogen of Phen. According to the magnetic moment and UV–vis. spectra the complexes were identified as octahedral geometries. The XRD analysis of the prepared compounds revealed that H2CPT and the complexes of Cr(III), Fe(III), Co(II) and Ni(II) display semi-crystalline peaks while, Cu(II) and Zn(II) complexes were crystalline in nature. The mechanism of the thermal degradation was identified and the kinetic parameters of the disintegration stages were assessed using Coats-Redfern (CR) and Horowitz-Metzger (HM) methods. DFT computations were used to calculate equilibrium geometric parameters and the lowest energy model structures. H2CPT, Phen and their metal complexes were examined for effectiveness towards two G(+), two G(-) bacteria and two fungi. Co(II) complex was significant, highly significant and very highly significant against all tested bacterial and fungi strains compared with H2CPT, Phen, references standard control and all other complexes.

Homo and heterometallic ruthenium and platinum complexes with multiple targets for therapeutic applications: a review

Abstract We are now well-positioned to comprehend carcinogenesis at a molecular level in greater detail due to significant technological advancements. Additionally, we are now able to rationally design and develop drug molecules with the ability to either selectively enhance or disrupt important biological processes, maximizing their therapeutic potential. This has heralded a new era in drug design. The heterometallic ruthenium–platinum complexes can be used as anticancer, photodynamic therapy, diabetes treatment, and molecular sensors for thiol-containing peptides due to their multifunctional interactions with nuclear DNA, mitochondrial DNA, RNA, and proteins. Compared to cisplatin and its Ru-based monometallic precursors, a significant number of reported ruthenium–platinum complexes exhibit enhanced cytotoxicity and tumor selectivity. Due to the covalent binding of the cis-PtIICl2 moiety to DNA, photoactive Ru(II)–Pt(II) complexes were designed to prelocalize a photodynamic therapy agent at the site of action. The development of ruthenium–platinum-based heterometallic complexes has recently advanced, opening up new avenues for the development of drugs that are more efficient. Metal complexes’ potential as important cancer therapeutic agents will be the primary focus of this review. The development of ruthenium and platinum-based mono and mixed-metal complexes with therapeutic and biomedical applications are discussed in detail in this article.

Chemical Manipulation of the Spin-Crossover Dynamics through Judicious Metal-Ion Dilution

In 2019, our groups described a unique FeII complex, [Fe(2MeL)(NCBH3)2] (2MeL = N,N'-dimethyl-N,N'-bis(2-pyridylmethyl)-1,2-ethanediamine) possessing a low-spin ground state that is not easily accessible due to the extremely slow dynamics of the high-spin to low-spin phase transition. Herein, we report the successful chemical manipulation of this spin-crossover (SCO) process through controlled metal-ion dilutions. The emergence or suppression of the thermally induced SCO behavior was observed depending on the radius of the metal ion used for the dilution (NiII or ZnII). Reversible photo-switching has been confirmed in all mixed-metal complexes whether the low-spin state is thermally accessible. Remarkably, the dilution with ZnII metal ions stabilizes HS FeII complexes with complete suppression of the thermally induced SCO process without destroying the reversible photoswitchability of the material.