Octahedral Geometry Research Articles

A polymeric copper complex based on a pyrazole derivative: Synthesis, spectroscopic, X‐ray, and biological activity studies

A novel 1D coordination polymeric copper complex based on 4‐(4′‐nitrophenylhydrazono)‐5‐trifluoromethyl‐2,4‐dihydropyrazol‐3‐one was prepared and characterized spectroscopically and thermally and via X‐ray crystallographic investigation. The prepared copper‐based structure was proved to have a 1D coordination polymer. X‐ray studies showed that the polymeric copper complex was of octahedral geometry, the ligand acted as a bidentate ligand, and the nitro group attached to the ligand acted as a bridging group. The cytotoxic activities of the copper polymer were evaluated including against MCF‐7 cells (breast cancer cell line), HepG‐2 cells (hepatocellular carcinoma), and HCT‐116 cells (colon cancer cell line). The morphological alterations of the complex treated cells were investigated using an inverted microscope. The cell cycle and apoptosis were evaluated and reported. The copper polymer exhibited the best antitumor activity against HepG‐2 cells (35.22 ± 4.80 μM) while also causing a decline in the G2/M phase and a remarkable enhancement in the early apoptosis.

Synthesis of biologically active cefpodoxime and vanillin-based schiff base metal complexes with the detailed biological evaluations.

Schiff bases of existing antimicrobial drugs are an area, which is still to be comprehensively explored to improve drug efficiency against consistently resisting bacterial species. In this study, we have targeted a new and eco-friendly method of condensation reaction that allows the "green synthesis" as well as improved biological efficacy. The transition metal complexes of cefpodoxime with well-enhanced biological activities were synthesized. The condensation reaction product of cefpodoxime and vanillin was further reacted with suitable metal salts of [Mn (II), Cu (II), Fe (II), Zn (II), and Ni (II)] with 1:2 molar ratio (metal: ligand). The characterization of all the products were carried out by using UV-Visible, elemental analyzer, FTIR, 1H-NMR, ICP-OES, and LC-MS. Electronic data obtained by UV-Visible proved the octahedral geometry of metal complexes. The biological activities Schiff base ligand and its transition metal complexes were tested by using in-vitro anti-bacterial analysis against various Gram-negative, as well as Gram-positive bacterial strains. Proteinase and protein denaturation inhibition assays were utilized to evaluate the products in-vitro anti-inflammatory activities. The in vitro antioxidant activity of the ligand and its complexes was evaluated by utilizing the 2,2-diphenyl-1-picrylhydrazyl(DPPH) in-vitro method. The final results proved metal complexes to be more effective against bacterial microorganisms as compared to respective parent drug as well as their free ligands. Patch Dock, a molecular docking tool, was used to dock complexes 1a-5e with the crystal structure of GlcN-6-P synthase (ID: 1MOQ). According to the docking results, complex 2b exhibited a highest score (8,882; ACE = -580.43kcal/mol) that is well correlated with a high inhibition as compared to other complexes which corresponds to the antibacterial screening outcomes.

Aroylhydrazone‐based nickel(II) complexes: Synthesis and their structural, density functional theory (DFT), biological and catalytic studies

Nickel(II) complexes of tridentate NNO donor aroylhydrazones, viz., di‐2‐pyridyl ketone‐4‐methoxybenzhydrazone monohydrate (DKMBH·H2O) and 2‐acetylpyrazine‐4‐methoxybenzhydrazone monohydrate (APMBH·H2O), were synthesized and characterized using various methods, including spectral techniques (Fourier transform infrared [FT‐IR], UV–vis) and analytical methods (elemental and X‐ray diffraction [XRD] analysis). Single‐crystal XRD was used to elucidate the crystal structures of nickel(II) complexes 1 and 2. The XRD analysis revealed that the respective ligands coordinated to the Ni(II) center through the deprotonated iminolate form in complex 1 and the neutral amido form in complex 2, resulting in distorted octahedral geometries. The ground state electronic configurations of the complexes were studied using the B3LYP/UB3LYP levels of DFT. Using absorption spectral titration methods, the interactions of complexes with CT‐DNA and bovine serum albumin (BSA) protein were examined. The observed data demonstrate that the complexes adopt an intercalative binding mode to bind to CT‐DNA and BSA protein. Additionally, the antioxidant activity of the nickel(II) complexes and their ligands was determined using 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH). Complex 2 demonstrated the highest radical scavenging activity of the compounds studied (IC50 = 3.81 mM). Furthermore, molecular docking studies were performed to understand how the complexes can interact with the SARS‐CoV‐2 main protease. The results revealed that complex 2 had the highest docking score (−8.18 kcal/mol) when compared with the other complexes under study. Aside from their biological properties, the nickel complexes heterogenized on functionalized SBA‐15 showed promising catalytic activity, achieving 98% yield in the reduction of nitrobenzene, forming exclusively aniline as the end product.

Iridium(III) carbene complexes as potent girdin inhibitors against metastatic cancers

Many cancer-driving protein targets remain undruggable due to a lack of binding molecular scaffolds. In this regard, octahedral metal complexes with unique and versatile three-dimensional structures have rarely been explored as inhibitors of undruggable protein targets. Here, we describe antitumor iridium(III) pyridinium-N-heterocyclic carbene complex 1a, which profoundly reduces the viability of lung and breast cancer cells as well as cancer patient-derived organoids at low micromolar concentrations. Compound 1a effectively inhibits the growth of non-small-cell lung cancer and triple-negative breast cancer xenograft tumors, impedes the metastatic spread of breast cancer cells, and can be modified into an antibody-drug conjugate payload to achieve precise tumor delivery in mice. Identified by thermal proteome profiling, an important molecular target of 1a in cellulo is Girdin, a multifunctional adaptor protein that is overexpressed in cancer cells and unequivocally serves as a signaling hub for multiple pivotal oncogenic pathways. However, specific small-molecule inhibitors of Girdin have not yet been developed. Notably, 1a exhibits high binding affinity to Girdin with a Kd of 1.3 μM and targets the Girdin-linked EGFR/AKT/mTOR/STAT3 cancer-driving pathway, inhibiting cancer cell proliferation and metastatic activity. Our study reveals a potent Girdin-targeting anticancer compound and demonstrates that octahedral metal complexes constitute an untapped library of small-molecule inhibitors that can fit into the ligand-binding pockets of key oncoproteins.

Impact on activation energy with elevating calcination temperature of barium bismuth ferrite nanocomposite

Barium Bismuth Ferrite nanoparticles having the general formula Ba1-xBixFeO3 were successfully made by the sol-gel system, using nitrates as the fundamental material. Tartaric acid and polyvinyl alcohol were used as chelating agents. The synthesized nanoparticle powder was sintered at 650 ̊C and 750 ̊C for 3 h. Filtering with dilute nitric acid and distilled water is used to remove the impurities. The structural, optical, and dielectric properties were determined at room temperature. Using X-ray diffraction (XRD) analysis, structure, lattice parameter, microstrain, and dislocation density were calculated. Using the Scherrer equation, the peak's crystalline size was ascertained. In FTIR, the vibrational modes of the octahedral and tetrahedral metal complexes in the sample have been studied using the wavenumber in this range. The synthesized nanocomposite contains morphological features, such as interconnecting agglomerates with spherical, irregular, or non-uniform elongated shapes, as demonstrated by SEM images. The activation energy for relaxation and activation energy for conduction was measured from the Cole-Cole plot and the AC conductivity versus frequency plot respectively. The determined activation energies from the two investigations were relatively close to one another. The Barium Bismuth Ferrite nanoparticles samples at room temperature indicate that the samples have implicit candidates for information storage devices for spintronic devices. In the high frequency range, all samples depending upon the temperature demonstrate excellent dielectric behaviour and small dielectric loss, and with stable dielectric constant, these samples make their prospective for the practical application in spintronic devices the main goal of this work.

Triaceto-nitrile-(1,4,7-trimethyl-1,4,7-tri-aza-cyclonona-ne)cobalt(II) bis-(tetra-phenyl-borate).

The title cobalt(II) complex, [Co(C2H3N)3(C9H21N3)](C24H20B)2 or [(tacn)Co(NCMe)3][BPh4]2, has been characterized by single-crystal X-ray diffraction. It incorporates the well-known macrocyclic tacn (1,4,7-trimethyl-1,4,7-tri-aza-cyclo-nona-ne) ligand, which is coordinated facially to the metal center. The complex crystallizes in space group P21/c with Z = 4. The divalent cobalt ion exhibits a six-coordinate octa-hedral geometry by one tacn and three aceto-nitrile ligands. Two non-coordinating tetra-phenyl-borate (BPh4 -) anions are also present.

Crystal structure of tris-{N,N-diethyl-N'-[(4-nitro-phen-yl)(oxo)meth-yl]carbamimido-thio-ato}cobalt(III).

The synthesis, crystal structure, and a Hirshfeld surface analysis of tris-{N,N-diethyl-N'-[(4-nitro-phen-yl)(oxo)meth-yl]carbamimido-thio-ato}cobalt(III) conducted at 180 K are presented. The complex consists of three N,N-diethyl-N'-[(4-nitro-benzene)(oxo)meth-yl]carbamimido-thio-ato ligands, threefold sym-metric-ally bonded about the CoIII ion, in approximately octa-hedral coordination, which generates a triple of individually near planar metallacyclic (Co-S-C-N-C-O) rings. The overall geometry of the complex is determined by the mutual orientation of each metallacycle about the crystallographically imposed threefold axis [dihedral angles = 81.70 (2)°] and by the dihedral angles between the various planar groups within each asymmetric unit [metallacycle to benzene ring = 13.83 (7)°; benzene ring to nitro group = 17.494 (8)°]. The complexes stack in anti-parallel columns about the axis of the space group (P), generating solvent-accessible channels along [001]. These channels contain ill-defined, multiply disordered, partial-occupancy solvent. Atom-atom contacts in the crystal packing predominantly (∼96%) involve hydrogen, the most abundant types being H⋯H (36.6%), H⋯O (31.0%), H⋯C (19.2%), H⋯N (4.8%), and H⋯S (4.4%).

New bioactive titanium(IV) derivatives with their DFT, molecular docking, DNA/BSA interaction, antioxidant and in-vitro investigations

A set of four new metallacyclic complexes titanium(IV) associated with Schiff bases (SBs) (1a- 1d) obtained by the specific reactions of β-diketones such as acetylacetone (acacH) and benzyl acetone (bzacH) and aminophenol derivatives while treating Ti(OPri)4 and these SBs individually in 1:2 stoichiometry under 8 h reflux condition in anhydrous benzene to afford as reddish powder (2a-2d). These products have been purified in repeated washings of dry n-hexane afterwards, subjected to characterization by suitable spectroscopic techniques (NMR, IR, UV–Vis and HRMS). These hexacoordinated complexes appeared as distorted octahedral geometry from computational data studies. The synthesized titanium(IV) complexes were screened for their antioxidant abilities where 2c and 2d exhibited remarkable activity as IC50 values. The DNA & BSA binding properties of the complexes (2a-2d) have also been investigated through electronic absorption and molecular docking analysis. The obtained results indicated clearly that the complexes got bound with DNA via groove binding mode according to the intrinsic binding constant values (Kb = 1.5 × 104 M−1 to 7.5 × 105 M−1). Derivative 2c was examined in-vitro on a panel of cancerous cell line − breast cancer and human colon cell lines MCF-7 to reflect IC50 results as 53.92 μg/mL and HT-29 33.43 μg/mL, respectively.

Crystallographic and electrochemical corrosion resistance analyses of cataphoretically co-deposited spinel Co>0.5Mn0.1-0.3O0.1-0.4@rGO composites over α-Fe(110) as current collector for supercapatteries

Binder free spinel Co>0.5Mn0.1-0.3O0.1-0.4@rGO composite electrode films were fabricated via galvanostatic electrochemical deposition technique over α-Fe(110) as current collector for hybrid supercapattery. Self-designed, n-MOSFET embedded ATMega328P microcontroller assisted modules were deployed to record the chronopotentiometric as well as galvanostatic charging-discharging analysis for specific capacitance (Cs) measurements. Partial, exchange as well as limiting current densities(iL) and cathodic current efficiency were estimated. Electrochemical signature was analyzed from cyclic voltammetry data. Morphology and chemical nature of the composites were scrutinized with scanning electron microscopy, X-ray photoelectron, FT-IR and Raman spectra. Indigenously designed computer simulation programs coded in Python were used to optimize the deposition parameters and to analyze the crystalline structure from XRD data. The unit cell length for the FCC crystal with an octahedral geometry was ∼ 4.28 Å. An in-depth analysis of potentiodynamic polarization as well as electrochemical impedance spectral data were carried out to scrutinize the corrosion resistance and capacitance characteristics of the composites in KOH. From the Tafel constants, Ecorr, Icorr, Ru, RCT and ZW data, it was accentuated that rGO incorporated composite films offer enhanced corrosion protection for Fe(110) substrates than their individual counterparts along with augmented specific capacitance. Estimated Cs was about 1166 F.g−1 at a scan-rate of 10 mV.s−1. Impact of time-constant (τ) and current density over Cs was analyzed via GCD technique and was about 1458.73 F.g−1 at 2 τ and at 0.5 A.g−1. And the corresponding specific energy and power density were about 183.23 W.h.kg−1 and 237.75 W.kg−1 respectively. These composite electrode films impregnated with rGO not only improved the specific capacitance but also imparts the sacrificial corrosion resistance over the α-Fe(110) as current collector in presence of OH−as electrolyte and can serve as a sustainable electrode material for supercapatteries.

Syntheses and crystal structures of the five- and sixfold coordinated complexes diiso-seleno-cyanato-tris-(2-methyl-pyridine N-oxide)cobalt(II) and diiso-seleno-cyanato-tetra-kis-(2-methyl-pyridine N-oxide)cobalt(II).

The reaction of CoBr2, KNCSe and 2-methyl-pyridine N-oxide (C6H7NO) in ethanol leads to the formation of crystals of [Co(NCSe)2(C6H7NO)3] (1) and [Co(NCSe)2(C6H7NO)4] (2) from the same reaction mixture. The asymmetric unit of 1 is built up of one CoII cation, two NCSe- iso-seleno-cyanate anions and three 2-methyl-pyridine N-oxide coligands, with all atoms located on general positions. The asymmetric unit of 2 consists of two cobalt cations, four iso-seleno-canate anions and eight 2-methyl-pyridine N-oxide coligands in general positions, because two crystallographically independent complexes are present. In compound 1, the CoII cations are fivefold coordinated to two terminally N-bonded anionic ligands and three 2-methyl-pyridine N-oxide coligands within a slightly distorted trigonal-bipyramidal coordination, forming discrete complexes with the O atoms occupying the equatorial sites. In compound 2, each of the two complexes is coordinated to two terminally N-bonded iso-seleno-cyanate anions and four 2-methyl-pyridine N-oxide coligands within a slightly distorted cis-CoN2O4 octa-hedral coordination geometry. In the crystal structures of 1 and 2, the complexes are linked by weak C-H⋯Se and C-H⋯O contacts. Powder X-ray diffraction reveals that neither of the two compounds were obtained as a pure crystalline phase.

Single molecule magnet behaviour of CoIIILnIII (Ln = TbIII, GdIII) compounds with compartmental Schiff base ligand and sulfonate co-ligands

In this research, our team synthesized and characterized two heteronuclear 3d-4f complexes, [CoIIICl(μ-valen)(μ-4-HBS)LnIII(NO3)(H2O)(4-HBS)], with Ln representing Tb (1) and Gd (2). Achievement of this was through the utilization of a compartmental Schiff base ligand H2valen, alongside secondary co-ligands Na(4-HBS) [H2valen=6,6′-((1E,1′E)-(ethane-1,2-diylbis(azaneylylidene))bis(methaneylylidene))bis(2-methoxyphenol); Na(4-HBS)=sodium 4-hydroxybenzenesulfonate]. X-ray crystallography revealed that both complexes feature a similar [Co(III)-Ln(III)] core, connected by the phenoxo-O atoms from the compartmental Schiff base ligand and the sulfonate-O atoms from the co-ligand. In this context, Co(III) displays a distorted octahedral geometry within a CoN2O3Cl coordination sphere, while Ln(III) exhibits a muffin (MFF)-like distorted geometry in a LnO9 coordination sphere. Magnetic analysis shows that the two complexes display unique magnetic properties. Complex 1 exhibits pronounced SMM behavior, with a notable energy barrier of 14.8 K for magnetization reversal. However, complex 2 presents a minor energy barrier of 4.8 K. Additionally, complexes 1 and 2 represent uncommon examples of dinuclear Co(III)-Ln(III) SMMs.

Synthesis, characterization, crystal structure, molecular dynamics simulations, MM-GBSA analysis, and bioactivity studies of pyrazine- and pyrimidine-modulated unsymmetrical dipyridylamide complexes

By using unsymmetrical pyrazine- and pyrimidine-modulated oligo-α-pyridylamine ligand N-(4-methylpyrimidin-2-yl)pyrazin-2-amine (Hmpmpza) (1), 1D copper(II) coordination polymer {[Cu(mpmpza)(CH3COO)](CH3OH)(H2O)}n (2) and mononuclear copper(II) complex [Cu(Hmpmpza)(NO3)2] (3) were first successfully synthesized and structurally characterized. In complex (2), Cu(II) is six-coordinated in an elongated octahedral geometry. The Hmpmpza molecule coordinates with the Cu(II) as a tridentate ligand, in which the pyrimidine and amine group nitrogen atoms link the coordination units to an infinite 1-D chain polymer. Extensive hydrogen bonds between amino groups, acetate anions, methanol, and water molecules are observed in 2, resulting in a 3D network of the 2. Complex 2 provides the first example of the complex with a modulated Hdpa ligand, in which nitrogen atoms both of the pyrazine and pyrimidine cycles participated in the coordination with the metal center. There are two crystallographically independent molecules in a mononuclear complex 3 and the Cu(II) atom is six-coordinated in an elongated octahedral geometry. Hmpmpza in complex 3 coordinates to the Cu(II) in an anti-anti conformation as a bidentate ligand. The hydrogen bonds between amino groups and coordinated nitrate anions in complex 3, link its molecules to a 1-D chain structure. However, no hydrogen bonding linkage between the 1-D chains is observed. The temperature dependence magnetic susceptibility measurement for complex 2 described by the Bonner-Fischer approximation shows a weak antiferromagnetic coupling between Cu(II) ions. The best fitting results were obtained with parameters g = 2.141, J = −0.73 cm−1 and R = 4.85 × 10−6. The molecular dynamics (MD) simulations of the 2-hAChE, 3-hAChE, 2-hBChE, and 3-hBChE complexes offer comprehensive insights into the stability and dynamic behavior of ligand-protein interactions. These findings contribute to a detailed understanding of the specific dynamics governing the stability of acetylcholinesterase and butyrylcholinesterase complexes.

Unique Use of Dibromo-L-Tyrosine Ligand in Building of Cu(II) Coordination Polymer-Experimental and Theoretical Investigations.

Although the crystals of coordination polymer {[CuCl(μ-O,O'-L-Br2Tyr)]}n (1) (L-Br2Tyr = 3,5-dibromo-L-tyrosine) were formed under basic conditions, crystallographic studies revealed that the OH group of the ligand remained protonated. Two adjacent [CuCl(L-Br2Tyr)] monomers, bridged by the carboxylate group of the ligand in the syn-anti bidentate bridging mode, are differently oriented to form a polymeric chain; this specific bridging was detected also by FT-IR and EPR spectroscopy. Each Cu(II) ion in polymeric compound 1 is coordinated in the xy plane by the amino nitrogen and carboxyl oxygen of the parent ligand and the oxygen of the carboxyl group from the symmetry related ligand of the adjacent [Cu(L-Br2Tyr)Cl] monomer, as well as an independent chlorine ion. In addition, the Cu(II) ion in the polymer chain participates in long-distance intermolecular contacts with the oxygen and bromine atoms of the ligands located in the adjacent chains; these intramolecular contacts were also supported by NCI and NBO quantum chemical calculations and Hirshfeld surface analysis. The resulting elongated octahedral geometry based on the [CuCl(L-Br2Tyr)] monomer has a lower than axial symmetry, which is also reflected in the symmetry of the calculated molecular EPR g tensor. Consequently, the components of the d-d band obtained by analysis of the NIR-VIS-UV spectrum were assigned to the corresponding electronic transitions.

Quantification of the Donor-Acceptor Character of Ligands by the Effective Fragment Orbitals.

Metal-ligand interactions are at the heart of transition metal complexes. The Dewar-Chat-Duncanson model is often invoked, whereby the metal-ligand bonding is decomposed into the simultaneous ligand→metal electron donation and the metal→ligand back-donation. The separate quantification of both effects is not a trivial task, neither from experimental nor computational exercises. In this work we present the effective fragment orbitals (EFOs) and their occupations as a general procedure beyond the Kohn-Sham density functional theory (KS-DFT) framework for the identification and quantification of donor-acceptor interactions, using solely the wavefunction of the complex. Using a common Fe(II) octahedral complex framework, we quantify the σ-donor, π-donor, and π-acceptor character for a large and chemically diverse set of ligands, by introducing the respective descriptors σd, πd, and πa. We also explore the effect of the metal size, coordination number, and spin state on the donor/acceptor features. The spin-state is shown to be the most critical effect, inducing a systematic decrease of the sigma donation and π-backdonation going from low spin to high spin. Finally, we illustrate the ability of the EFOs to rationalize the Tolman electronic parameter and the trans influence in planar square complexes in terms of these new descriptors.

Synthesis, Characterization, and Catalytic Performance of a New Heterobimetallic Y/Tb Metal-Organic Framework with High Catalytic Activity.

A three-dimensional heterobimetallic porous structure with the formula {[Y3.5Tb1.5L6(OH)3(H2O)1.5 (DMF)1.5] n ·1.5H2O·DMF} n (L = 3-amino-4-hydroxybenzoate) (Y/Tb-MOF) has been synthesized and characterized by single crystal and powder X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), inductively coupled plasma mass spectrometry (ICP-MS), electrophoretic mobility, and Fourier transform infrared (FTIR) spectroscopy. The structure presents two metal environments: a bioaugmented isosceles wedge (mm2) MO8 and a tricapped trigonal prism (-6m2) MN3O6. These configurations facilitate the creation of channels with a diameter of 10.7 Å, enabling its utilization as an active catalyst where the heterobimetallic nature of the assembly will be explored. This mixed-metal metal-organic framework has been tested in the cycloaddition of epoxides with carbon dioxide as well as in the cyanosilylation and hydroboration reactions of carbonylic substrates. Additionally, a monometallic Tb-MOF analogue has been synthesized for comparative evaluation of their catalytic performances. Both the mixed metal and monometallic variants exhibit outstanding activity in the cyanosilylation and hydroboration of carbonyls and in the synthesis of carbonates under CO2 pressure. However, only the latter exhibits high recyclability.

1D heteronuclear coordination polymers of hexacyanocobaltate(III) with 2-hydroxymethylpyridine

Three new hexacyanocobaltate(III) complexes, {[M2(hmpy)4Co(µ-CN)4(CN)2]∙2H2O}n (M = Cu(II) (1), Zn(II) (2) and Cd(II) (3)) were synthesized with 2-hydroxymethylpyridine (hmpy) ligand, and characterized by vibration (FT-IR and Raman) spectral, single crystal X-ray diffraction (SC-XRD) and powder X-ray diffraction (PXRD), thermal and elemental analyses techniques. The crystallographic analyses revealed that cyanide complexes 1–3 are infinite one-dimensional coordination polymers. Each M ion is coordinated by two nitrogen and two oxygen atoms from the hmpy ligands and two nitrogen atoms from the cyanide ligands, displaying a distorted octahedral coordination geometry. Similarly, each Co(III) ion is coordinated by six carbon atoms from cyanide ligands to form a distorted octahedral coordination geometry. These complexes form 3D supramolecular networks through OH···O hydrogen bonds and CH···N interactions. Additionally, structural analyses such as metal salts, pH values of the compounds obtained under different conditions were evaluated. A synthesis-structural analyses relation was made from these data.

Octahedral molybdenum cluster complex with glycolate ligands and study of its activity in polyurethane polymerization process

Octahedral metal clusters [{M6X8}L6]2– (where M = Mo2+ or W2+, X = Cl–, Br– or I–, and L is an apical ligand typically with a charge of 1–) have shown promise in a great variety of applications, ranging from solar energy and catalysis to cancer diagnostics and therapy. However, these clusters are not stable in water – the most widely used medium in many practical fields. An effective way to utilize and stabilize these compounds is to incorporate them into organic matrices. Along with direct impregnation, clusters can be used as monomers in polymerization process due to the ease of an addition of polymerizable functional groups in cationic part or in apical ligand environment. In this work, new cluster with six terminal glycolate ligands, (Bu4N)2[{Mo6I8}(OOCCH2OH)6], has been obtained and studied using FTIR, TGA, EDX, etc. Cluster luminescence has been studied in the temperature range of 77–300 K. As have been demonstrated experimentally and theoretically, by the DFT calculations, the coordination of glycolic acid to the cluster drastically reduces the activity of the –OH group in the polymerization of polyurethane.

New Series of Ni(II), Cu(II), Zr(IV), Ag(I), and Cd(II) Complexes of Trimethoprim and Diamine Ligands: Synthesis, Characterization, and Biological Studies

New compounds series of [M(TMP)(en)]X·nH2O and [M(TMP)(PD)]X·nH2O, where M = Ni2+, Cu2+, Zr4+, Ag+, Cd2+, TMP = trimethoprim, en = ethylenediamine, PD = o-phenylene and X= Cl− or NO3−, were prepared. The compounds were characterized using techniques including melting points, conductance, elemental analysis, FTIR, NMR, and mass spectroscopy. FTIR spectra indicated TMP acted like a bi-dentate ligand, combining via the nitrogen atoms of azomethine and pyrimidine amino groups. Diamine ligands (en or o-PD) are coordinated via two nitrogen atoms. Prepared compounds showed monomeric behavior and adopted a 6-coordinate octahedral geometry based on magnetic susceptibility and UV spectra. Conductivity measurements revealed Zr(IV) compounds were 1:2 conductive, while Ag+ and Cd2+ were 1:1 conductive; Ni2+ and Cu2+ compounds were non-conductive. Antibacterial tests on compounds and ligands against Bacillus subtilis and Staphylococcus aureus demonstrated broad-spectrum antibacterial activity. The mixed metal compounds revealed an observable tendency of antibacterial activity in the order Zr > Cd = Ag > Cu, making Zr(IV) compounds the most biologically active among them against S. aureus (Gram-positive) while the same compounds showed less antibacterial activity against B. subtilis (Gram-negative) than the free ligand.

Evaluation of DNA and BSA-Binding, Nuclease Activity, and Anticancer Properties of New Cu(II) and Ni(II) Complexes with Quinoline-Derived Sulfonamides

Four complexes of essential metal ions, Cu(II) and Ni(II), with the new sulfonamide ligand N-(pyridin-2-ylmethyl)quinoline-8-sulfonamide (HQSMP) were synthesized and physicochemically and structurally characterized. Complex [Cu(QSMP)Cl]n (2) consists of a polymeric chain formed by distorted square pyramidal units. In 2, the sulfonamide ligand acts as a bridge coordinating to one Cu(II) through its three N atoms and to another metal ion via one O atom in the sulfonamido group, while the pentacoordinate complex [Cu(QSMP)(C6H5COO)] (3) presents a highly distorted square pyramidal geometry. Complex [Ni(QSMP)(C6H5COO)(CH3OH)][Ni(QSMP)(CH3COO)(CH3OH)] (4) consists of two mononuclear entities containing different anion coligands, either a benzoate or an acetate group. Both units exhibit a distorted octahedral geometry. The interaction of the complexes with CT-DNA was studied by means of UV-Vis and fluorescence spectroscopy, interestingly revealing that the Ni(II) complex presents the highest affinity towards the nucleic acid. Complexes 1 and 2 are able to cleave DNA. Both compounds show promising nuclease activity at relatively low concentrations by mediating the production of a reactive oxygen species (ROS). The interaction of the four complexes with bovine serum albumin (BSA) was also investigated, showing that the compounds can bind to serum proteins. The antitumor potential of complexes 1 and 2 was evaluated against the A549 lung adenocarcinoma cell line, revealing cytotoxic properties that were both dose- and time-dependent.

Investigation of structural, physical and optical properties of sodium boro-tellurite glasses doped with iron oxide

In this work, we demonstrate systematic studies on the influence of Fe2O3 on the structural and optical properties of transparent B2O3–TeO2–Na2O glasses containing the different concentrations of Fe2O3. The glasses were prepared via the standard melt quenching method, and the prepared glasses were characterized using, XRD, electron paramagnetic resonance (EPR), FTIR, and UV–visible spectroscopic techniques. Furthermore, we evaluated several physical properties of the glasses, including densities, molar volume, boron-boron separation, and oxygen packing density, with respect to the concentration of Fe2O3 in the host glass matrix. It is observed that the density of the glasses and the average boron-boron distance found increase with Fe2O3 concentration due to the modification in the glass network induced by the dopant ions. EPR spectra reveals the presence resonance signals at g ∼2.04 and g ∼4.26, hence it proves the existence of Fe3+ in distorted octahedral coordination and supported by UV–Vis absorption bands. The FTIR spectra revealed an increase in spectral intensity with the concentration of Fe2O3. This was attributed to the formation of non-bridging oxygens through converting BO4 units into BO3 units, which Fe2O3 mediated. The UV–visible spectral analysis showed a decreased energy band gap from 2.26 to 1.51 eV with increased Fe2O3 concentration. Additionally, we determined the Urbach energy, refractive index, optical basicity, and electronegativity, which are presented in detail.