Fe Complexes Research Articles

Enhancement of gas adsorption on transition metal ion-modified graphene using DFT calculations.

Graphene-based nanomaterial was widely used in gas sensors, detection, and separation. However, weak adsorption and low selectivity of the pristine graphene used for gas sensors are major problems. Here, using density functional theory (DFT) calculations, we reported the significant increase of four gas molecules (N2, CO2, C2H2, and C2H4) adsorption on the transition metal ion (Fe3+, Co2+, Ni2+)-modified graphene complex (Fe3+/Co2+/Ni2+-G) comparing to be absorbed on the pristine graphene (G). Moreover, the Co2+-G is suitable for the selective separation of C2H4/C2H2 due to the larger adsorption energy difference (8.5kcal/mol) between them. The addition of transition metal ions also decreased the HOMO-LUMO gap of the systems, which benefits the enhancement of electrical conductivity. This suggests that the transition metal ion-modified graphene can be used to distinguish the different gas molecule's adsorption, facilitating the design of graphene-based gas sensors and selective separation. All the density functional theory (DFT) calculations were performed by B3LYP with the GD3 dispersion method using Gaussian 16 software. The basis set 6-31G(d) was used for C, H, O, and N atoms, and Lanl2DZ was used for transition metal ions (Fe3+, Co2+, Ni2+). The DOS analysis and energy decomposition analysis were performed using the Multiwfn program.

Regulating the coordination environment of atomically dispersed Fe-N4 moieties in carbon enables efficient oxygen reduction for Zn-air batteries

Fe-N-C single-atom catalysts exhibit the highest oxygen reduction reaction catalytic activity among reported transition metal-based SACs. However, the intrinsic activity of atomically dispersed Fe-N4 moieties in carbon limits the ORR catalytic activity of current Fe-N-C. This work describes a simple method for synthesizing single-atom catalysts with atomically dispersed FeN4CxSy active sites, referred to as FeZ-N/S0.6-C. It also developed a radical polymerization approach to encapsulate ZnCl2 and [Fe(Phen)3]3+ within a polyacrylamide matrix. Due to abundant -CO and –NH2 groups in polyacrylamide, the Zn2+ and Fe complexes could be evenly distributed throughout the polymer. Subsequent one-step pyrolysis allowed the generation of nitrogen-sulfur co-doped catalysts with well-defined pore structures and uniform active sites. The introduction of S atoms by ammonium persulfate extended the Fe-N bond of the Fe-N4 moiety, while the ZnCl2 template aided in fine-tuning the channels within the catalyst. As a result, the FeZ-N/S0.6-C catalyst showed a record high half-wave potential (E1/2 = 0.93 V vs. RHE) among the reported non-noble metal catalysts regulated by S elements. Moreover, FeZ-N/S0.6-C-based aqueous Zn-air and quasi-solid Zn-air batteries achieved excellent performance and showed great application potential in energy storage and conversion devices. This work provides a new approach to encapsulate metal ions in polymers and optimize the single-atom catalyst structure by heteroatom doping to enhance the performance for sustainable applications.

MACE: Automated Assessment of Stereochemistry of Transition Metal Complexes and Its Applications in Computational Catalysis.

Computational chemistry pipelines typically commence with geometry generation, well-established for organic compounds but presenting a considerable challenge for transition metal complexes. This paper introduces MACE, an automated computational workflow for converting chemist SMILES/MOL representations of the ligands and the metal center to 3D coordinates for all feasible stereochemical configurations for mononuclear octahedral and square planar complexes directly suitable for quantum chemical computations and implementation in high-throughput computational chemistry workflows. The workflow is validated through a structural screening of a data set of transition metal complexes extracted from the Cambridge Structural Database. To further illustrate the power and capabilities of MACE, we present the results of a model DFT study on the hemilability of pincer ligands in Ru, Fe, and Mn complexes, which highlights the utility of the workflow for both focused mechanistic studies and larger-scale high-throughput pipelines.

Three novel mononuclear 4‐vinylpyridine‐based Fe(III) complexes displaying various spin‐crossover behaviour

AbstractThree novel mononuclear 4‐vinylpyridine‐based Fe(III) complexes [FeL(4‐VP)]BPh4 (4‐VP=4‐vinylpyridine; H2L=bis(salicylicdeneaminopropyl)amine, H2salten, 1; H2L=bis(salicylicdeneaminopropyl)methylamine, H2saltenMe, 2; H2L=bis(3‐methoxysalicylideneaminopropyl)methylamine, 3‐OMeH2saltenMe, 3) were synthesized and characterized. Single‐crystal X‐ray diffraction analyses revealed that 1–3 both present the mononuclear structure based on 4‐VP coordinated with bis(salicylicdeneaminopropyl)amine and its derivatives, which give 2D architectures by various interactions among cations and counter‐ions. Magnetic studies showed that both 1 and 2 exhibit one‐step complete spin‐crossover (SCO) behaviours with critical transition temperatures (T1/2) of 178 and 87 K respectively, while 3 exhibits one‐step incomplete spin crossover behaviour (T1/2,3=93 K). The introduction of methyl groups on the amine nitrogen of the Schiff base ligands in 2 and 3 give the bigger repulsive effect, further decrease the cooperation of spin centres, resulting in their spin transition occurring at lower temperatures. In addition, the presence of C−H⋯O weak interactions in 1 and 3 with synergistic effect, led to their spin transition temperatures being higher than that of 2.

Is Mn(I) More Promising Than Fe(II)-A Comparison of Mn vs Fe Complexes for Olefin Metathesis.

Olefin metathesis is one of the most significant transformations in organic chemistry and is an excellent example for efficient homogeneous catalysis. Although most currently used catalysts are primarily based on 4d and 5d metals, cycloaddition and cycloreversion reactions can also be attributed to first-row transition metals, such as Fe. Surprisingly, the potential of Mn(I)-based catalysts for olefin metathesis has been unexplored despite their prominence in homogeneous catalysis and their diagonal relationship to Ru(II). In the present study, we have investigated the prospective capabilities of Mn complexes for cycloaddition and reversion reactions using density functional theory. Therefore, we have initially compared the literature known iron model systems and their isoelectronic Mn counterparts regarding their reactivity and electronic structure. Next, we constructed potential Mn complexes derived from synthetically accessible species, including carbonyl ligands and obeying octahedral geometry. Based on thermodynamic parameters and the calculation of electronic descriptors, we were able to validate the isodiagonal relationship. Our study serves as guidance for the experimental chemist.

Structural, photophysical, and electrochemical redox properties of meso-tetrakis(pentafluorophenyl)porphyrins

This study delineates the synthesis and comprehensive characterization of metal complexes of meso-tetrakis(pentafluorophenyl)porphyrin (H2TPF[Formula: see text]P, 1) with first-row transition metal ions (M = Mn(III) 2, Fe(III) 3, Co(II) 4, Ni(II) 5, Cu(II) 6, and Zn(II) 7) to elucidate their structural, electronic spectral, and electrochemical redox properties. Co, Ni, Cu and Zn Complexes exhibit planar structure ([Formula: see text]24 = 0.003-0.021 Å and [Formula: see text]C[Formula: see text] = 0.004−0.041 Å) which is also confirmed by the single crystal data of complex ZnTPF[Formula: see text]P, 7 shows the planar geometry, while Fe and Mn complexes show the slightly nonplanar structure ([Formula: see text]24 = 0.101–0.143 Å and [Formula: see text]C[Formula: see text] = 0.080–0.112 Å), which are distorted due to their occupied axial sites by −Cl ligand as revealed by density functional theory (DFT) calculations. Furthermore, electronic spectroscopy revealed a gradual bathochromic shift following the order of NiTPF[Formula: see text]P < CoTPF[Formula: see text]P < CuTPF[Formula: see text]PCl < H2TPF[Formula: see text]P = FeTPF[Formula: see text]PCl < ZnTPF[Formula: see text]P < MnTPF[Formula: see text]PCl by appending different metal ions in the porphyrin core. MnTPF[Formula: see text]PCl exhibited the most significant bathochromic shift ([Formula: see text] = 63 nm) in the Soret band compared to H2TPF[Formula: see text]P. Also, MnTPF[Formula: see text]PCl and FeTPF[Formula: see text]PCl show a unique pattern of split Soret band at around 364 and 345 nm due to the interaction between the metal [Formula: see text]-orbitals and the surrounding ligands. The electrochemical redox potentials of the filled 3d orbital of Zn endow ZnTPF[Formula: see text]P (ring centered) with the lowest oxidation potential.

Designing, Characterization, DFT, Biological Effectiveness, and Molecular Docking Analysis of Novel Fe(III), Co(II), and Cu(II) Complexes Based on 4-Hydroxy-2H-pyrano[3,2-c]quinoline-2,5(6H)-dione.

The main target of the current framework is the designing and synthesizing of novel iron(III), cobalt(II), and cupper(II) complex compounds emanating from bioactive nucleus, 4-hydroxy-2H-pyrano[3,2-c]quinoline-2,5(6H)-dione ligand, to enhance comprehension as potential antibacterial, antifungal, and antioxidant alternatives by means of using DFT calculations and molecular docking investigation. Thus, the new complexes had been synthesized and characterized using various analytical techniques, including elemental analysis, infrared spectroscopy, mass spectrometry, UV spectroscopy, conductivity, and magnetic testing, as well as thermal analysis. The 4-hydroxy-2H-pyrano[3,2-c]quinoline-2,5(6H)-dione ligand exhibits monobasic bidentate OO donor properties toward the metal core, as shown by its infrared spectroscopic characteristics. The use of thermal analysis techniques allows for the identification and characterization of water molecules present inside the complexes, as well as the determination of their distribution patterns. The molecular structures of free ligand and its metal complex compounds have been verified through the use of density functional theory (DFT) simulations. These simulations also provide a valuable understanding of the quantum chemical characteristics associated with these structures. In vitro experiments were conducted to evaluate the antioxidant, antibacterial, as well as antifungal and the properties of the free ligand and its corresponding complex compounds. DATA revealed that synthesized metal complex compounds have heightened biological efficacy as related to the unbound ligand. Furthermore, molecular docking analysis was done to understand the interactions between the studied compounds and proteins derived from Escherichia coli (pdb ID: 2vf5), Aspergillus flavus (pdb ID: 3cku), and humans (pdb ID: 5IJT), which are considered to be significant in drug design. Lastly, a correlation between in vitro efficacies with molecular docking data was done and analyzed.

Co(II), Mn(II), and Fe(III) complexes of water‐soluble hydrazone bearing 2‐nicotinoylhydrazineylidene moiety: Preparation, characterization, cyclic voltammetry, computational and biological studies

A water‐soluble hydrazone ligand bearing 2‐nicotinoylhydrazineylidene moiety, sodium 4‐hydroxy‐3‐([2‐nicotinoylhydrazineylidene]methyl) benzenesulfonate (NaH2NH), and its complexes with Co(II), Fe(III), and Mn(II) have been synthesized and characterized. The structure of the ligand and its complexes were analyzed using various spectroscopic techniques such as FT‐IR, 1H‐ and 13C‐NMR, EI‐mass, powder X‐ray diffraction, UV–visible spectra, and magnetic measurements. The infrared spectra indicated that the ligand behaves as a negatively charged bidentate ligand (ON) through the deprotonation of the enolic (OH) group and the azomethine (C=N) group in the [Co (NaHNH)2(H2O)4Cl2].3H2O complex. In the [Fe (NaNH)2(H2O)Cl].2H2O complex, the ligand behaves as bi‐negative tetradentate (O2N2) through the protonation of the enolic oxygen and the nitrogen atom of the azomethine group in two nicotinic hydrazone molecules. Another coordination type was observed for [Mn (NaNH)(H2O)3] complex in which NaH2NH acts as bi‐negative tridentate ONO through the nitrogen atom of the azomethine group, the protonated of enolic and phenolic groups. The fluorescence spectrum of the NaH2NH was found to be quenched upon addition of these Co(II) and Mn(II) ions. The antimicrobial results indicated that the Mn(II) complex exhibited the highest antibacterial potency against all targeted organisms. The results of antioxidants demonstrated that the complexes exhibited higher activity compared to the free ligand, indicating an enhancement of antioxidant activity through complexation. The tested substances established strong nuclease‐like activity at a high concentration of 7.5 mM, leading to the complete degradation of DNA as observed in agarose gel electrophoresis. This suggests that these compounds have the potential to serve as antitumor agents in vivo by inhibiting DNA replication in cancer cells and preventing tumor growth. The interaction of the isolated compounds with 1c14 and 6vj3 targets was discussed using molecular docking.

Solid State Synthesis, Spectroscopic, X-ray and Antibacterial Studies of Zn(II) and Fe(III) Complexes of Pyridine-3-Carboxamide and 2-Hydroxybenzoic Acid

Solid State Synthesis, Spectroscopic, X-ray and Antibacterial Studies of Zn(II) and Fe(III) Complexes of Pyridine-3-Carboxamide and 2-Hydroxybenzoic Acid

Ce and Fe complexes as potent antifungal agents for wallpapers

The current research focused on the Schiff base ligand (S,E)-2-((2-hydroxy-3-methoxy- benzylidene)amino)-3-(1H-imidazol-4-yl)propanoic acid which synthesis by reacting L-histidine and 2-hydroxy-3-methoxy-benzaldehyde. Its complexes with Ce(III) and Fe(III) both in bulk and nano size were also synthesized. The ligand and its metal complexes were characterized by various physicochemical methods such as FT-IR, 1H NMR, 13C NMR, electronic spectra, XRD, TGA, and SEM. The synthesized ligand and its metal complexes were screened against different fungi. It was found from the results that the cerium nano complex shows a potent antifungal activity for indoor uses as wallpapers.
 KEY WORDS: Schiff base ligands, Nano complexes, Ce nano complexes, Wallpapers
 Bull. Chem. Soc. Ethiop. 2024, 38(2), 365-383. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i2.7

Spectroscopic and Theoretical Investigation of High-Spin Square-Planar and Trigonal Fe(II) Complexes Supported by Fluorinated Alkoxides.

The electronic structures and spectroscopic behavior of three high-spin FeII complexes of fluorinated alkoxides were studied: square-planar {K(DME)2}2[Fe(pinF)2] (S) and quasi square-planar {K(C222)}2[Fe(pinF)2] (S') and trigonal-planar {K(18C6)}[Fe(OC4F9)3] (T) where pinF = perfluoropinacolate and OC4F9 = tris-perfluoro-t-butoxide. The zero-field splitting (ZFS) and hyperfine structure parameters of the S = 2 ground states were determined using field-dependent 57Fe Mössbauer and high-field and -frequency electron paramagnetic resonance (HFEPR) spectroscopies. The spin Hamiltonian parameters were analyzed with crystal field theory and corroborated by density functional theory (DFT) and ab initio complete active space self-consistent field (CASSCF) calculations. Whereas the ZFS tensor of S has a small rhombicity, E/D = 0.082, and a positive D = 15.17 cm-1, T exhibits a negative D = -9.16 cm-1 and a large rhombicity, E/D = 0.246. Computational investigation of the structural factors suggests that the ground-state electronic configuration and geometry of T's Fe site are determined by the interaction of [Fe(OC4F9)3]- with {K(18C6)}+. In contrast, two distinct countercations of S/S' have a negligible influence on their [Fe(pinF)2]2- moieties. Instead, the distortions in S' are likely induced by the chelate ring conformation change from δλ, observed for S, to the δδ conformation, determined for S'.

Stabilization of NH- Group Adjacent to Naked Silicon(II) Atom in Base Stabilized Aminosilylenes.

Aminosilylene, comprising reactive NH- and Si(II) sites next to each other, is an intriguing class of compounds due to its ability to show diverse reactivity. However, stabilizing the reactive NH- group next to the free Si(II) atom is challenging and has not yet been achieved. Herein, we report the first examples of base stabilized free aminosilylenes Ar*NHSi(PhC(Nt Bu)2 ) (1 a) and Mes*NHSi(PhC(Nt Bu)2 ) (1 b) (Ar*=2,6-dibenzhydryl-4-methylphenyl and Mes*=2,4,6-tri-tert-butylphenyl), tolerating a NH- group next to the naked Si(II) atom. Remarkably, 1 a and 1 b exhibited interesting differences in their reactivity upon heating. With 1 a, an intramolecular C(sp3 )-H activation of one of the benzhydryl methine hydrogen atoms to the Si(II) atom produced the five-membered cyclic silazane 2. However, with 1 b, a rare 1,2-hydrogen shift to the Si(II) atom afforded a silanimine 3, with a hydride ligand attached to an unsaturated silicon atom. Further, the coordination capabilities of 1 a were also tested with Ru(II) and Fe(0) precursors. Treatments of 1 a with [Ru(η6 -p-cymene)Cl2 ]2 led to the isolation of a η6 -arene tethered complex [RuCl2 {Ar*NHSi(PhC(t BuN)2 )-κ1 -Si-η6 -arene}] (4), whereas with the Fe(CO)5 precursor a Fe(0) complex [Fe(CO)4 {Ar*NHSi(PhC(t BuN)2 )-κ1 -Si}] (5) was obtained. Density functional theory (DFT) calculations were conducted to shed light on the structural, bonding, and energetic aspects in 1-5.

Stabilization of NH− Group Adjacent to Naked Silicon(II) Atom in Base Stabilized Aminosilylenes

AbstractAminosilylene, comprising reactive NH− and Si(II) sites next to each other, is an intriguing class of compounds due to its ability to show diverse reactivity. However, stabilizing the reactive NH− group next to the free Si(II) atom is challenging and has not yet been achieved. Herein, we report the first examples of base stabilized free aminosilylenes Ar*NHSi(PhC(NtBu)2) (1 a) and Mes*NHSi(PhC(NtBu)2) (1 b) (Ar*=2,6‐dibenzhydryl‐4‐methylphenyl and Mes*=2,4,6‐tri‐tert‐butylphenyl), tolerating a NH− group next to the naked Si(II) atom. Remarkably, 1 a and 1 b exhibited interesting differences in their reactivity upon heating. With 1 a, an intramolecular C(sp3)−H activation of one of the benzhydryl methine hydrogen atoms to the Si(II) atom produced the five‐membered cyclic silazane 2. However, with 1 b, a rare 1,2‐hydrogen shift to the Si(II) atom afforded a silanimine 3, with a hydride ligand attached to an unsaturated silicon atom. Further, the coordination capabilities of 1 a were also tested with Ru(II) and Fe(0) precursors. Treatments of 1 a with [Ru(η6‐p‐cymene)Cl2]2 led to the isolation of a η6‐arene tethered complex [RuCl2{Ar*NHSi(PhC(tBuN)2)‐κ1‐Si‐η6‐arene}] (4), whereas with the Fe(CO)5 precursor a Fe(0) complex [Fe(CO)4{Ar*NHSi(PhC(tBuN)2)‐κ1‐Si}] (5) was obtained. Density functional theory (DFT) calculations were conducted to shed light on the structural, bonding, and energetic aspects in 1–5.

Synthesis of Hydrazide Derivative of Betulinic Acid, Its Organometallic Complexes, Characterization and Bioassay.

Betulinic acid and its derivatives comprehend an immense prospective toward the development of cytotoxic, antiviral, antimicrobial and antioxidant agents. Cisplatin (cytotoxic drug) divert the attentions to develop organometallic compounds with pronounced biological activities. The current study was aimed for the first time to synthesize, characterize and evaluate biologically a series of metal (Fe, Cu, Zn, Sn and Sb) complexes of betulinic acid hydrazide. First step involved the formation of hydrazide derivative of betulinic acid (ligand) by modification at C-28 carboxylic acid moiety of betulinic acid with hydrazine followed by the synthesis of its metal complexes using salts of different metals (Fe, Cu, Zn, Sn and Sb). Physical state, melting point, Fourier-transform infrared (FT-IR) and 1 H nuclear magnetic resonance (1 H-NMR) spectral techniques were used to characterized the ligand and its metal complexes. Agar well diffusion method and agar tube dilution assay were performed to evaluate its antibacterial and antifungal activities respectively. DPPH assay was carried out to develop antioxidant properties by the reported methods.

Synthesis and Reactivity of Fe(II) Complexes Containing Cis Ammonia Ligands.

The development of earth-abundant transition-metal complexes for electrocatalytic ammonia oxidation is needed to facilitate a renewable energy economy. Important to this goal is a fundamental understanding of how ammonia binds to complexes as a function of ligand geometry and electronic effects. We report the synthesis and characterization of a series of Fe(II)-NH3 complexes supported by tetradentate, facially binding ligands with a combination of pyridine and N-heterocyclic carbene donors. Electronic modification of the supporting ligand led to significant shifts in the FeIII/II potential and variations in NH bond acidities. Finally, investigations of ammonia oxidation by cyclic voltammetry, controlled potential bulk electrolysis, and through addition of stoichiometric organic radicals, TEMPO and tBu3ArO• are reported. No catalytic oxidation of NH3 to N2 was observed, and 15N2 was detected only in reactions with tBu3ArO•.

Mn(III) O^N^O Complexes as Water-tolerant and Environmentally Benign Catalysts for Polyurethane Foam Synthesis.

Polyurethanes are synthesized on industrial scale by the reaction of diisocyanates with diols in the presence of catalysts which are commonly based on tin complexes and amines. However, due to the toxicity and volatility of these tin catalysts and amines, there is the need to develop new catalysts that are more environmentally benign. Herein, we report the synthesis of O^N^O pincer-ligated Mn(III) and Fe(III) complexes that serve as suitable catalysts for urethane formation and are stable to hydrolysis as predicted by computations and observed experimentally. The O^N^O pincer scaffold is vital to the activity of these catalysts, simultaneously ensuring increased solubility in the reaction medium as well as providing a stable framework upon dissociation of co-ligands in the catalytic cycle. In silico mechanistic investigations for urethane formation show that the stabilization of active species in square-planar geometries enabled by these O^N^O ligands permit the simultaneous coordination of alcohol and isocyanate in suitable configuration at the metal center.

Dinitrogen Activation Mediated by the (P2PPh)Fe Complex: Electronic Structure, Dimerization Mechanism, and Magnetic Coupling.

Herein, we report the estimation of the extent of dinitrogen activation by different charged and structural forms of (P2PPh)Fe biomimetic catalysts, which, in the presence of light, exhibit significant yield in the N2-to-NH3 conversion. Complete active space self-consistent field (CASSCF) calculations have been used to determine the electronic structure of different reduced forms of the mononuclear complexes: the neutral (P2PPh)Fe(N2)2 adduct and the anionic [(P2PPh)Fe(N2)]- and [(P2PPh)Fe(N2)]2- complexes. These calculations also revealed that the extent of reduction of a dinitrogen molecule reaches up to one electron (N21-) due to the back-bonding from the Fe center, in agreement with the changes observed in the vibration frequency of the N-N bond in these complexes. In addition, the energy profile of the dimerization of the mononuclear (P2PPh)Fe(N2)2 complex to the dinuclear mono-N2-bridged [(P2PPh)Fe]2(μ-N2) complex has been determined by means of density functional theory (DFT) calculations. A three-step mechanism has been proposed for the dimerization, favored by both kinetics and thermodynamics criteria. Finally, the magnetic coupling constant in the diiron (μ-N2) complex is estimated from CASSCF/NEVPT2 calculations. Such a dinuclear complex presents a strong antiferromagnetic coupling resulting from the interaction between two S = 1 d6 Fe2+ ions, bridged by a highly activated dinitrogen molecule (N22-) with two electrons on the π* orbitals.

Homoleptic metal complexes derived from hydrazones as ligand; synthesis, cytotoxic activity, photoluminescence properties and ADMET studies

In the present work, N'-(2‑hydroxy-5-nitrobenzylidene)thiophene-2-carbohydrazide (L) and its Cu(II), Ni(II), Co(II), and Fe(II) complexes have been prepared. Their chemical structures were characterized by elemental analysis, molar conductivity, FT-IR, UV–Vis, TGA, LC-MS/MS, 1H and 13C NMR (for ligand). Also, the photoluminescence properties of the free ligand and its metal complexes were investigated in DMF solution. The ligand is emissive at 430–630 nm range and the emission band is almost turned off upon complexation with Cu(II) and Fe(II) ions. Emission spectra of the Ni(II) and Co(II) complexes showed a blue shift compared to the free ligand. Also, in vitro cytotoxic activities of both ligand and its metal complexes against HTB-54 and BEAS-2B cells have been investigated. The [Fe(L)2]⋅2H2O complex (IC50 35.59 μM) showed better cytotoxic activity than cisplatin against HTB-54 cells. Moreover, the ligand and its Fe(II) complex had slight cytotoxic activity against BEAS-2B cell line.

Designing of novel nano-sized coordination compounds based on Spinacia oleracea extract: Synthesis, structural characterization, molecular docking, computational calculations, and biomedical applications

A novel series of nano-sized metal chelates of 1-((E)-(2-mercaptophenylimino)methyl)naphthalen-2-ol (H2L) Azo-methine ligand with Fe(III), Ni(II) and Ag(II) were prepared and investigated for antitumor activities. The structures of all the synthesized compounds have been analyzed using various physicochemical techniques. The results showed a distorted square-planar geometry for Ni2L2 and AgL, whereas the geometry around the FeL complex is octahedral. The nano-sized Fe and Ag complexes were prepared in an easy, rapid andeco-friendly way using Spinacia oleracea (SO) extract in EtOH. X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV.Vis. spectra were used to assess the structural characteristics and particle size of the newly produced nano-sized Fe and Ag complexes. Furthermore, from TGA, we investigated the impact of heat on the particle size of newly prepared compounds. The geometry optimization of the prepared complexes and various quantum chemical parameters were computed by Gaussian 09 softwares. The results showed that all of the metal complexes studied are more stable than the free ligand H2L, with the Ni2L2 complex being the most stable. All micro- and nano-complexes were tested for in vitro anticancer activities, and the results revealed inhibition of cancer cell activity, although the smaller size is better than the larger size. The liver cancer and COVID‑19 were screened using molecular docking to determine the possible binding energy of inhibitors.

Development of Anticancer Ferric Complex Based on Human Serum Albumin Nanoparticles That Generate Oxygen in Cells to Overcome Hypoxia-Induced Resistance in Metal Chemotherapy.

To achieve the remarkable therapeutic efficacy of a ferric (Fe) complex via a reactive oxygen species (ROS) mechanism in solid tumors, a therapeutic Fe-based Schiff-base complex (Fe1) was synthesized and encapsulated in human serum albumin (HSA) nanoparticles (NPs), which generated oxygen (O2) in cancer cells in situ. The HSA-Fe1-O2 NP (HSA-Fe1-O2NP) delivery system effectively overcame hypoxia-induced resistance in metal chemotherapy, alleviated the hypoxic condition of tumor tissues, and showed excellent tumor suppression by generating excess ROS and promoting the apoptosis of SK-N-MC tumor cells. The HSA-Fe1-O2NPs not only enhanced the ability of the Fe1 complex to target tumor cells but also decreased adverse effects in vivo.