Mn Complexes Research Articles

Cytotoxicity of photoactivatable tricarbonyl Mn(I) complex with 1-(chloromethyl)-1H-benzotriazole against leukaemia

The reaction between bromo pentacarbonyl manganese(I) and two equivalents of 1-(chloromethyl)-1H-benzotriazole (BTZ-CH2Cl) afforded visible-light induced carbon monoxide releasing molecule of the general formula, fac-[MnBr(CO)3(BTZ-CH2Cl)2]. The solvatochromism, dark-stability and photolysis profile of the titled complex was examined in organic solvents with various hydrogen-bonding propensities, coordinating capabilities, and solvent polarities as well as in the presence of proteins. The number of CO equivalents released from the titled complex upon the exposure to a 468 nm LED light was determined using myoglobin assay. The titled complex displayed selective cytotoxicity towards human acute monocytic leukaemia in the dark without causing any harmful effect to the normal mice bone marrow stromal cells.

Bioactive Thiosemicarbazone Coordination Metal Complexes: Synthesis, Characterization, Theoretical analysis, Biological Activity, Molecular Docking and ADME analysis.

Mn(II) and Cu(II) complexes having the formula [M(L)2 ]X2 of ligand, i. e., 2-acetyl-5-methylfuranthiosemicarbazone were synthesized. Various analytical and spectroscopic techniques described the structure of synthesized complexes. Molar conductance confirmed the electrolytic nature of the complexes. The theoretical study of the complexes explained the structural property and reactivity. The chemical reactivity, interaction and stability of the ligand and metal complexes were studied with the help of global reactivity descriptors. MEP analysis was used to investigate the charge transfer in the ligand. The biological potency was evaluated against two bacteria and two fungi. Complexes demonstrated superior inhibitory action to ligand. The inhibitory effect was also checked at the atomic scale using molecular docking, which confirmed the experimental results. Cu(II) complex was shown to have the most inhibitory effect in experimental and theoretical studies. To check the bioavailability and drug-likeness, ADME analysis was also done.

Exploring Triboluminescence and Paramagnetism: A Rapid Mn Complex Synthesis for High School and Undergraduate Chemistry Laboratories

Exploring Triboluminescence and Paramagnetism: A Rapid Mn Complex Synthesis for High School and Undergraduate Chemistry Laboratories

Synthesis, characterization, and biological activity assessment of new metal complexes of Schiff bases produced from benzoin

By the reaction of Benzoin with melamine and Benzoin with 5-aminosalysilc acid a new Schiff base is obtained the reaction of the legends with Mn++, Zn++, and Ag + salts leads to the complexes [M (L)2 ] X at PH=7-6, and [M (L)2 ] at PH=9-10, L= BMA, BMS M= Mn++ Zn++ and Ag +, Several chemical and physical measurements, such as melting point, molar conductivity, and magnetic properties, as well as FT-IR spectroscopy, UV-VIS spectroscopy element analysis (C.H.N.), and (1 H-NMR)spectroscopy, and GC-MASS. was used to identify the produced ligands and complex structures, the complexes of Mn++, and Znand ++ give hexacoordinated complexes having the shape octane al but Ag+ gives tetracoordinate complexes. having shape tetrahedral. then they were screened for biological activity using agar plate diffusion technique against Gram(+) (Staphylococcus aureus bacteria, pseudomonas aeruginosa bacteria) and Gram(−) (Escherichia coli bacteria, Klebsiella pneumonia bacteria) When compared to streptomycin and trimethoprim drug, all these ligands and their complexes show good antimicrobial effectualness.

First-principles molecular dynamics simulation study on Ti/Mn ions in aqueous sulfuric acid for use in redox flow battery

The effect of the Ti4+ ion on the structural and chemical features of the Mn3+ ion in aqueous sulfuric acid was investigated using first-principles molecular dynamics (FPMD) simulation and second-order perturbation theory (CASPT2) with a complete active space self-consistent field (CASSCF) reference function. The focus was on the role of the Ti ion in the MnO2 formation reaction from the Mn3+ ion. The simulations showed that Mn3+ forms two types of complexes, [Mn(H2O)4(SO4)2]1− and [Mn(H2O)6]3+ in aqueous sulfuric acid with Ti ions where the population of the former was found to be higher than that of the latter. We found that when the HSO4− ion was coordinated to a Ti4+ ion, it released one proton, which increases proton concentration in the solution. Detailed quantum chemical calculations on the isolated Mn complexes show that if the Mn complexes interact with a hydronium ion, the stability of Mn3+ ion is increased to a large extent. Such a result implies that the increased local proton concentration due to Ti4+ ions hinders formation of MnO2 particle.

Synthesis, characterization and anticancer potency of novel Mn(II), Co(II), and Cu(II) complexes based on N-[(1E)-1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)ethylidene]-2-(4-methylanilino)acetohydrazide

Synthesis, characterization and anticancer potency of novel Mn(II), Co(II), and Cu(II) complexes based on N-[(1E)-1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)ethylidene]-2-(4-methylanilino)acetohydrazide

Synthesis, Characterization, Antimicrobial, Density Functional Theory, and Molecular Docking Studies of Novel Mn(II), Fe(III), and Cr(III) Complexes Incorporating 4-(2-Hydroxyphenyl azo)-1-naphthol (Az).

This work synthesized three new CrAz2, MnAz2, and FeAz2 complexes and investigated them using IR, mass, UV spectroscopy, elemental analysis, conductivity and magnetic tests, and thermogravimetric analysis. The azo-ligand, 4-(2-hydroxyphenylAzo)-1-naphthol (Az), couples with metal ions via its nitrogen (in -N=N- bonds) and oxygen (in hydroxyl group) atoms, according to the IR spectra of these complexes. Through thermal examination (TG/TGA), the number and location of water in the complexes were also determined. Density functional theory (DFT) theory is applied to ameliorate the structures of the ligand (Az) and metal complexes and analyze the quantum chemical characteristics of these complexes. The antifungal and antibacterial activity of the ligand and its complexes opposed to several hazardous bacteria and fungi was investigated in vitro. Metal complexes were discovered to have a higher inhibitory impact on some organisms than the free ligand. The MnAz2 complex exhibited the best activity among the studied materials, whereas the CrAz2 complex had the lowest. The compounds' binding affinity to the E. coli (PDB ID: 1hnj) structure was predicted using molecular docking. Binding energies were calculated by analyzing protein-substrate interactions. These encouraging findings imply that these chemicals may have physiological effects and may be valuable for a variety of medical uses in the future.

Anticancer and antimicrobial activities of a novel 4-nitrobenzohydrazone and the Cu(II), Ni(II), Co(II), and Mn(II) complexes

Antimicrobial and anticancer activities against prostate (PC-3) and breast (MCF-7) cancer cells by Schiff base derived from novel 4-Nitrobenzohydrazone ligand and its Cu(II), Ni(II), Co(II), and Mn(II) complexes are reported in this study. Characterizations by conventional spectroscopic techniques and elemental analyses suggest successful syntheses. The cobalt complex, Co(HL)2 was found to be moderately effective on both Pseudomonas aeruginosa ATCC 35032 and Candida albicans ATCC 10231, other compounds did not affect the test microorganisms. Results indicated that the compounds are effective on both prostate and breast cell lines at concentrations between 5 and 40 μM, and exhibit their effects by apoptotic mechanisms. The complex Mn(HL)2 could be a potential candidate against prostate cancer cells (PC-3). The interactions of ligand and complexes with biological targets were predicted by molecular docking which indicated high binding affinities, and artificial neural network explained their anticancer activities. Density functional theoretical calculations corroborated experimental findings.

Synthesis and Characterization of 4-amino-N'-[(1E)-1-(2-hydroxy-6-methyl-4-oxo-4H-pyran-3-yl)ethylidene]benzohydrazide and its Cu(II), Ni(II), Zn(II) and Mn(II) Complexes

New benzohydrazone compound, 4-amino-N'-[(1E)-1-(2-hydroxy-6-methyl-4-oxo-4H-pyran-3-yl)ethylidene] benzohydrazide (HL1) and its Cu(II), Ni(II), Zn(II) and Mn(II) complexes were synthesized. The structures of HL1 and its complexes were elucidated by elemental analysis and IR, UV-Vis, 1H and 13C NMR spectroscopy and mass spectrometry. The infrared spectral data of the complexes revealed that HL1 coordinated with the metal ions through azomethine nitrogen, enolic oxygen and amide carbonyl oxygen atoms, hence, HL1 behaves as a monobasic tridentate ligand. UV-Vis data revealed that Zn(II) and Mn(II) complexes adopted octahedral geometry, while Cu(II) and Ni(II) complexes had five-coordinate and square-planar geometries respectively. The mass spectra data and elemental analysis values are in accordance with the calculated values for the suggested molecular formula of the complexes, a confirmation of the 1:1 ligand to metal stoichiometry in case of Cu(II) complex and 2:1 ligands to metal stoichiometry in case of the other complexes.

Synthesis and characterization of some transition and inner transition mixed ligand complexes derived from Schiff base ligand and o-aminophenol

By the condensation reaction of benzophenone with naphthalene-1,8-diamine, a bidentate NN Schiff base ligand (L) was obtained. The preparation and structural characterization of mixed ligand chelates derived from Schiff base ligand as a primary ligand and o-aminophenol (o-AP) as a secondary ligand, were also reported. The synthesized Schiff base ligand and its transition and inner transition mixed ligand chelates were characterized based on elemental analyses, FT-IR, mass, 1H-NMR, UV-Vis., molar conductivity and magnetic studies. Thermogravimetric studies were also investigated to determine the thermal stability and degradation of the metal complexes. An octahedral geometry was suggested for all complexes based on spectroscopic and magnetic studies. The surface morphology of the Schiff base ligand and Mn(II) complex confirmed their nano-size. The mass spectra of Schiff base ligand and Er(III) mixed ligand complex pointed out the fair agreement between the calculated and found values. In-vitro antimicrobial activities of Schiff base ligand, o-aminophenol and the mixed ligand complexes were investigated against different pathogenic bacterial and fungal species. The anticancer activity of the new compounds had been also studied towards breast cancer (MCF-7). Molecular docking of the Schiff base ligand was also reported.

Synthesis, Characterization and Antimicrobial Properties of Mixed-Ligand Complexes of Some Metal(II) Ions with Barbituric Acid and 1,10-Phenanthroline Ligands

Many pathogenic organisms have developed resistance to many antibiotics, which leads to an increase in the spread of many microbial infections. There is an urgent need to find more effective drugs to curb widespread transmission. Hence, this study synthesized and evaluated the antimicrobial activities of mixed-ligand complexes of Cu(II), Co(II), Ni(II), Mn(II), and Zn(II) ions with barbituric acid and 1,10 phenanthroline ligands in effort to find more effective antibiotics. The complexes were characterized using elemental analysis, metal analysis, melting points, solubility tests, and spectroscopic analyses (IR and UV-visible). The antimicrobial activities of the complexes were evaluated against two gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), two gram-negative bacteria (Pseudomonas aeruginosa and Clostridium spp.), and four pathogenic fungi (Candida albicans, Aspergillus flavus, Aspergillus niger, and Saccharomyces cerevisiae). The biological activities of the metal complexes were compared to the activities of some conventional antibiotics. The molecular formulas for the complexes in 1:1:1 (L-M-L) were established based on the results of the elemental and metal analyses. The IR spectroscopic data results showed the coordination of 1,10-phenanthroline to the metal ions through the nitrogen donor atom, while barbituric acid coordinated with the metal ions through nitrogen and oxygen atoms. The formation of the complexes was confirmed by UV-visible spectroscopic data. Many of the mixed-ligand metal complexes demonstrated higher biological activities than the standard drugs and also succeeded where the conventional antibiotics failed. Therefore, the metal complexes could be considered as more efficacious antibiotics that could be added to the arsenal of effective antibiotics for the prevention of the intrinsic problems of multidrug resistance.
 Keywords: Bacteria, Fungi, Ligands, Metal complexes, Multidrug resistance, Barbituric acid

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.

Manganese(I)-Catalyzed Chemoselective Transfer Hydrogenation of the C=C Bond in Conjugated Ketones at Room Temperature.

Chemoselective transfer hydrogenation of C=C bond in α,β-unsaturated ketones is demonstrated at room temperature employing a manganese(I) catalyst and half an equivalent of ammonia-borane (H3 N-BH3 ). A series of mixed-donor pincer-ligated Mn(II) complexes, (tBu2 PN3 NPyz )MnX2 [κP ,κN ,κN -(N-(di-tert-butylphosphaneyl)-6-(1H-pyrazol-1-yl)pyridin-2-amine)MnX2 ] {X=Cl (Mn2), X=Br (Mn3), X=I (Mn4)} were synthesized and characterized. Amongst the Mn(II) complexes, (Mn2, Mn3, Mn4) and Mn(I) complex, (tBu2 PN3 NPyz )Mn(CO)2 Br (Mn1) screened; the Mn1 acts as an efficient catalyst for the chemoselective C=C bond reduction in α,β-unsaturated ketones. Various synthetically important functionalities like halides, methoxy, trifluoromethyl, benzyloxy, nitro, amine, and unconjugated alkene and alkyne groups, including heteroarenes, were compatible and provided saturated ketones in excellent yields (up to 97 %). A preliminary mechanistic study highlighted the crucial role of metal-ligand (M-L) cooperation through the dearomatization-aromatization process in catalyst Mn1 for the chemoselective C=C bond transfer hydrogenation.

Heteronuclear Fe(III)/Mn(III) salen complex as electron transfer mediator for laccase-based biocathodes: Structural investigations, molecular docking, and electrochemical studies

A novel hetero-trinuclear Fe(III)/Mn(III) complex derived from a salen ligand has been investigated using elemental analysis, infrared spectroscopy, and single-crystal X-ray crystallography. The studied complex crystallized as orthorhombic with the Mn(III) ion coordinated in the equatorial plane by the phenolate O and imine N atoms of the ligand. Two axial positions are taken up by an O atom from water and a N atom from the cyanide group. The [Fe(CN)6] core in the crystal structure links the two [Mn(salen)(H2O)] moieties together. In addition, the isolated complexes have been utilized as mediators for the electron transfer between the laccase and the electrode. Moreover, using structural data for the laccase, computational docking simulations were also performed towards the hydrophobic pocket on the surface of the laccase to determine how the complex behaved in the vicinity of a so-called hydrophobic pocket on the surface outside of the Type-1 site. Additionally, the parameters of mediator concentration, temperature, and electrode conditions (CNT, MXene) were used to investigate the electron transfer mechanism.

Novel Nanogels Loaded with Mn(II) Chelates as Effective and Biologically Stable MRI Probes.

Here it is described nanogels (NG) based on a chitosan matrix, which are covalently stabilized by a bisamide derivative of Mn-t-CDTA (t-CDTA = trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid). the Mn(II) complex acts both as a contrast medium and as a cross-linking agent. These nanogels are proposed as an alternative to the less stable paramagnetic nanogels obtained by electrostatic interactions between the polymeric matrix and paramagnetic Gd(III) chelates. The present novel nanogels show: i) relaxivity values seven times higher than that of typical monohydrated Mn(II) chelates at the clinical fields, thanks to the combination of a restricted mobility of the complex with a fast exchange of the metal-bound water molecule; ii) high stability of the formulation over time at pH 5 and under physiological conditions, thus excluding metal leaking or particles aggregation; iii) good extravasation and accumulation, with a maximum contrast achieved at 24h post-injection in mice bearing subcutaneous breast cancer tumor; iv) high T1 contrast (1 T) in the tumor 24h post-injection. These improved properties pave the way for the use of these paramagnetic nanogels as promising magnetic resonance imaging (MRI) probes for in vitro and in vivo preclinical applications.

Anticancer Activity and Mode of Action of Cu(II), Zn(II), and Mn(II) Complexes with 5-Chloro-2-N-(2-quinolylmethylene)aminophenol.

Developing a new generation of anticancer metal-based drugs that can both kill tumor cells and inhibit cell migration is a promising strategy. Herein, we synthesized three Cu(II), Zn(II), and Mn(II) complexes derived from 5-chloro-2-N-(2-quinolylmethylene)aminophenol (C1-C3). Among these complexes, the Cu(II) complex (C1) showed significantly greater cytotoxicity toward lung cancer cell lines than cisplatin. C1 inhibited A549 cell metastasis and suppressed the growth of the A549 tumor in vivo. In addition, we confirmed the anticancer mechanism of C1 by triggering multiple mechanisms, including inducing mitochondrial apoptosis, acting on DNA, blocking cell cycle arrest, inducing cell senescence, and inducing DNA damage.

Cu(II) and Mn(II) Anchored on Functionalized Mesoporous Silica with Schiff Bases: Effects of Supports and Metal-Ligand Interactions on Catalytic Activity.

New series of Cu(II) and Mn(II) complexes with Schiff base ligands derived from 2-furylmethylketone (Met), 2-furaldehyde (Fur), and 2-hydroxyacetopheneone (Hyd) have been synthesized in situ on SBA-15-NH2, MCM-48-NH2, and MCM-41-NH2 functionalized supports. The hybrid materials were characterized by X-ray diffraction, nitrogen adsorption-desorption, SEM and TEM microscopy, TG analysis, and AAS, FTIR, EPR, and XPS spectroscopies. Catalytic performances were tested in oxidation with the hydrogen peroxide of cyclohexene and of different aromatic and aliphatic alcohols (benzyl alcohol, 2-methylpropan-1-ol, and 1-buten-3-ol). The catalytic activity was correlated with the type of mesoporous silica support, ligand, and metal-ligand interactions. The best catalytic activity of all tested hybrid materials was obtained in the oxidation of cyclohexene on SBA-15-NH2-MetMn as a heterogeneous catalyst. No leaching was evidenced for Cu and Mn complexes, and the Cu catalysts were more stable due to a more covalent interaction of the metallic ions with the immobilized ligands.

Synthesis, spectroscopic characterization, crystal structure, DFT and Hirschfeld surface analysis of a manganese(I) complex ([Mn(P-NH-NH-P)(CO)2][BPh4

We report the synthesis of a new Mn—PNNP complex ([Mn(P-NH-NH-P)(CO)2][BPh4]) with an original approach for the synthesis of a previously reported PNNP ligand PPh2(o-C6H4)NHCH2CH2NH(o-C6H4)PPh2 using a new protocol in a less toxic solvent. The PNNP ligand forms a stable mononuclear Mn(I) complex in a low spin state with the additional coordination of two carbonyl groups. This new complex has been characterized by elemental analysis, 1H, 13C and 31P NMR spectroscopy, FTIR spectroscopy and HRMS studies. The molecular structure of the complex was determined by X—ray diffraction analysis, which confirmed its distorted octahedral geometry with the linear tetradentate ligand in a rare cis-α-configuration. Additionally, theoretical calculations were performed on the optimized structure of the complex using the functional-basis-set combination B3PW91/6―311++G (d, p)/SDD which showed good correlation with the experimental data. The frontier molecular orbital analysis revealed a large HOMO to LUMO gap (4.66 eV) as expected for a low spin, d6 octahedral metal complex with the HOMO concentrated on the Mn centre. The Hirschfeld surface analysis signalled the important intermolecular H…H and C…H interactions. A preliminary catalytic study of the complex on transfer hydrogenation of acetophenone was conducted.

Modeling of photofunctional transition metals (Mn, Re, Ir) complexes towards the effective detection of uric acid (UA) as biomarker for kidney dysfunction

The potential of isatinic quinolyl Schiff bases transition metal complexes as electronic biosensors for detecting kidney dysfunction biomarker (uric acid) denoted as UA was investigated from first principles computations. The adsorption of UA onto the metal centres of Ir, Mn and Re complexes of (Z)-5-bromo-3-(quinolin-8-ylimino)indolin-2-one and (Z)-5-nitro-3-(quinolin-8-ylimino)indolin-2-one, designated as L1 and L2 were studied extensively. Uric acid has been considered an essential biomarker for oxidative stress, human arthritis, cardiomyopathy, and hyperuricemia. Biomarkers perform a pivotal role in the successful diagnosis and treatment of several diseases. Dispersion-corrected DFT calculations were performed, and the results evinced that the modelled transition metal complexes are promising candidates for UA detection. It was found that UA is chemisorbed by coordinating with the metal centers and ligands at a 3.873 Å distance on average with the adsorption enthalpies being −37.11 kcal/mol, –32.95 kcal/mol, and −21.44 for UA@L2Mn, UA@L2Re and UA@L2Ir complexes respectively. While the computed adsorption enthalpies for L1 complexes were found to be −24.47 kcal/mol. –22.11 kcal/mol and –22.19 kcal/mol respectively for UA@L1Ir, UA@L1Mn and UA@L1Re complexes showing that the L2 complexes acted as better sensors for UA. The sensitivity of UA by the metal complexes was influenced by the binding conformation of UA and the adsorption sites of the ligands. Overall, the metal complexes demonstrated high sensitivity with high values of work function up to 7.13 eV being recorded and hence making suitable substrates for work-function based sensors. Good stability and excellent conductivity even with the adsorption of UA was maintained and the desorption test-based on the transition state theory was considered and the complexes showed promising results for practical implementation as UA biosensors.

Manganese catalyzed direct regio- and stereoselective hydroxylation of 5α- and 5β-androstane derivatives

Herewith we report late-stage catalytic selective oxidative functionalization of several steroids with a common gonane core, namely androstane derivatives 5α-androsterone-3-acetate, 5β-androstan-17β-ol-3-one (etiocholan-17β-ol-3-one), 17β-acetoxy-5β-androstan-3-one, and 5β-pregnane-3,20-dione, at C–H groups in the presence of chiral bis-amino-bis-pyridylmethyl and structurally related Mn complexes, using H2O2 as terminal oxidant. Depending on the steric demand and absolute chirality of the catalyst, mono-hydroxylation at A, B, or C rings is achieved in up to 58% isolated yield. Strongly hydrogen-bond donating solvent hexafluoroisopropanol (HFIP) effectively protects the C17–OH group in etiocholan-17β-ol-3-one from ketonization, thus providing an opportunity to obtain 6,17- and 12,17-dihydroxy androstane derivatives without using protecting groups.