Search

The success of platinum-based chemotherapeutic drugs for clinical cancer treatments has inspired tremendous research efforts on developing new metallic anticancer agents with improved cytotoxic activity and reduced side effects. 2,2′;6′,2″-Terpyridine and its 4′-substituted derivatives have showed great potential as ligand compartments for designing new anticancer drug candidates involving base metals. In this work, we synthesized a series of cobalt and iron coordination compounds based on 4′-pyridyl-2,2′;6′,2″-terpyridine, including homoleptic complexes, a dinuclear bridged complex and 1- and 2-dimensional coordination polymers/networks. The polymorphism of two homoleptic CoII and FeII complexes has been described along with the structural characterization of a CoII coordination polymer and dinuclear FeIII complex by X-ray crystallography. These compounds were tested preliminarily as precatalysts for the regioselective hydrosilylation of styrene. Their cytotoxic activities against two human breast cancer cell lines (MCF-7 and MDA-MB 468) and a normal breast epithelial cell line (MCF-10A) were investigated in order to observe the best-performing drug candidates. [ABSTRACT FROM AUTHOR]

A simple, cheap, and portable Arduino-based photometer was constructed and used to determine cobalt(II) after extraction by a thin film microextraction strip. The paired emitter-detector diodes configuration was employed for making the photometer. A polymer inclusion membrane was applied to fabricate the thin film microextraction strip. The optimization of the polymer membrane composition was done by response surface methodology (RSM). The optimized membrane was obtained containing 40.8% (w/w) of polyvinyl chloride, 45.0% of (2-ethylhexyl) phosphoric acid extractor, 1.3% of 1-(2-pyridylazo)-2-naphthol as the complexing agent and 12.9% of tri-butyl phosphate plasticizer. The variables affecting microextraction efficiency were optimized to be 0.05 M of sodium sulfate, pH 6.0, and extraction time of 120 min at room temperature (22 ± 1 °C). The analytical performance included a linear range between 3 and 200 µg L−1 with detection and quantitation limits of 1 and 3 µg L−1, respectively. The intra-day and inter-day precision were less than 2.9 and 6.2%, respectively. Finally, the method was used to determine cobalt in the water and tablets. Relative recovery for the tap water sample was from 94 to 111%. [ABSTRACT FROM AUTHOR]

AbstractCobalt is beneficial for human activity but has adverse effects when discharged in large quantities. Therefore, its precise and accurate quantification in samples is of importance. Here, a natural deep eutectic solvent (NADES), composed of camphor (H-bond acceptor) and menthol (H-bond donor), has been used for the preconcentration of Co(II) from water samples before determination by a spectrophotometer at 398 nm. The 8-hydroxyquinoline-Co(II) complex was transferred to the NADES using air-assisted dispersive liquid-liquid microextraction (AA-DLLME). The extraction efficiency was enhanced through fine tuning of various parameters, including pH, NADES volume, and quantity of dispersant. Similarly, the centrifugation rate and time, quantity of the complexing agent, matrix effects, and salt concentration were also evaluated. Under the optimized conditions, an enrichment factor of 37.5 and a preconcentration factor of 37.5 were obtained. The limits of detection (LOD) and quantification (LOQ) were 0.44 µg/L and 1.47 µg/L, respectively. For seven replicates of 50 µg/L Co(II), the relative standard deviation was 3.2%. The developed method was employed for the determination of Co(II) in water samples, with quantitative recovery values from 94.5 to 98.5%. [ABSTRACT FROM AUTHOR]

The combination of spin crossover (SCO) with chirality has caught increasing research interest owing to its potential applications in the fields of multifunctional magnetic molecular materials and devices. In this work, we synthesized a pair of homochiral Co(II) SCO complexes and their racemic complex by applying chiral Schiff base terimine ligands modified by naphthyl group. Single‐crystal X‐ray diffraction results showed that the chiral ligands retained chirality after coordination with Co(II) ion, giving rise to a pair of enantiomeric Co(II) complexes in the RR and SS configurations, respectively. The circular dichroism spectroscopy demonstrated the enantiomeric nature of the homochiral complexes. The enantiomers exhibited similar thermally induced SCO, while the racemate was trapped in the high spin state. The differences in SCO behavior between the homochiral and racemic complexes are attributed to different supramolecular interactions. This work provides a feasible approach to constructing new chiral SCO materials and offers perspectives in developing switchable nonlinear optical magnetic materials. [ABSTRACT FROM AUTHOR]

In this work, we have studied the stability constants of ternary cobalt(II) complexes with the primary ligands: pyridine-2,3-dicarboxylic acid (H22,3-Dipic, H2L) and pyridine-3,4-dicarboxylic acid (H23,4-Dipic, H2L) and secondary ligands representing low molecular mass components of blood serum: lactic acid (HLac), oxalic acid (H2Ox), citric acid (H3Cit), and phosphoric acid (H3PO4). Potentiometric data were analyzed using the least squares computational program LETAGROP. Ionic strength and temperature were both kept constant using 1.0 mol dm−3 NaNO3 as ionic medium at 25 °C. Species distribution diagrams were generated to determine the speciation variations with respect to pH. [ABSTRACT FROM AUTHOR]

The success of platinum-based chemotherapeutic drugs for clinical cancer treatments has inspired tremendous research efforts on developing new metallic anticancer agents with improved cytotoxic activity and reduced side effects. 2,2′;6′,2″-Terpyridine and its 4′-substituted derivatives have showed great potential as ligand compartments for designing new anticancer drug candidates involving base metals. In this work, we synthesized a series of cobalt and iron coordination compounds based on 4′-pyridyl-2,2′;6′,2″-terpyridine, including homoleptic complexes, a dinuclear bridged complex and 1- and 2-dimensional coordination polymers/networks. The polymorphism of two homoleptic CoII and FeII complexes has been described along with the structural characterization of a CoII coordination polymer and dinuclear FeIII complex by X-ray crystallography. These compounds were tested preliminarily as precatalysts for the regioselective hydrosilylation of styrene. Their cytotoxic activities against two human breast cancer cell lines (MCF-7 and MDA-MB 468) and a normal breast epithelial cell line (MCF-10A) were investigated in order to observe the best-performing drug candidates.

The study investigates the adsorption of heavy metals (HMs), specifically Cd(II) and Co(II), from aqueous solutions using synthesized iron oxides with layered structures and surface groups of a basic nature: goethite α-FeO(OH), lepidocrocite γ-FeO(OH), and ferrihydrite Fe(OH)3. The results indicate that these crystalline materials are effective in adsorbing heavy metals within pH ranges typical of natural aquatic environments (7.5). We determined the conditions for extracting heavy metals, examining the effect of pH in aqueous solutions, ionic strength, adsorbent dosage, and major components of natural waters. The results show that the majority of HM ions are extracted within the first 30 min of contact between the aqueous solution and the solid phase of the adsorbents, with adsorption equilibrium being reached for iron-containing adsorbents in approximately 4 h. To account for the relative distribution of HM species in aqueous environments with varying pH values, we calculated the distribution of these species for the concentrations studied in model water solutions, enabling an evaluation of the extraction mechanism. The adsorption of Co(II) and Cd(II) is primarily driven by the interaction of their cationic forms with ferrinol surface groups of the studied iron-containing minerals through chemisorption from aqueous solutions within the investigated pH range. The adsorption limits for goethite and ferrihydrite are nearly identical, while those for lepidocrocite are significantly lower, which can be attributed to their structure and the availability of active adsorption sites. The shape of the adsorption isotherm curves is also quite similar across the entire concentration range. Based on the data obtained regarding the adsorption efficiency of Cd(II) and Co(II), which are among the most challenging cations to remove using adsorption methods, the synthesized goethite and ferrihydrite can be recommended as cost-effective and efficient materials for the purification of natural waters contaminated with heavy metals. [ABSTRACT FROM AUTHOR]

The synthesis of a series of mononuclear, dicationic CoII funnel complexes is reported herein. Three ligands Calix‐TMPAX present a calix[6]arene cone closed at its small rim by a tris(2‐pyridylmethyl)amine (TMPA) unit and differ by the nature of three cavity walls, anisole, phenol or quinone. The X‐ray diffraction structure of [CoII(MeCN)Calix‐TMPAOMe](ClO4)2 displays a trigonal bipyramidal geometry, with Co bound to all 4 nitrogen atoms of the TMPA cap, and to one MeCN guest molecule buried inside the calixarene cavity. All complexes were fully characterized in solution as high spin 5‐coordinate species using various techniques, including 1H NMR spectroscopy. For comparison purpose, an analogous CoII complex based on the TMPACH2OH ligand, devoid of a calixarene core, was synthetized. Its X‐ray structure shows a dicationic 7‐coordinate cobalt(II) center in the N4O3 environment provided by the ligand, leaving no space for exogenous ligand binding. This contrasts with the 5‐coordinate complexes obtained with the calix‐ligands that allow guest‐ligand binding and exchange. A brief overview of the coordination properties of the calix‐complexes, compared to those obtained with TMPA ligands, devoid of a cavity, highlights major differences in terms of complexation kinetics, geometry, coordination to the labile site, anion affinity, nuclearity, and stability. [ABSTRACT FROM AUTHOR]

The direct two‐step synthesis of new coordination polymer [Co2(pyz)(tfa)2(dmf)6(H2O)][Co3(μ3‐F)(tfa)6(pyz)(dmf)]2 ⋅ 2dmf, (where pyz=pyrazine, Htfa=trifluoroacetic acid, dmf=dimethyl formamide) containing the fluoro‐centered secondary building block [Co3(μ3‐F)(tfa)6], is reported. The substance characterization using single‐crystal XRD, powder XRD, IR‐spectroscopy and thermogravimetry was performed. SCXRD data revealed the presence of cationic and anionic subsystems, both containing cobalt(II) ions and pyrazine bridging ligands. The magnetic proper‐ties of the compound were collected and discussed. Temperature dependence of magnetic susceptibility shows Curie–Weiss like behavior at all studied temperatures. [ABSTRACT FROM AUTHOR]

Selective oxidation of alcohols towards carbonyl‐based products, such as aldehydes, is a subject of significant interest in the field of catalysis. Herein, a Zn‐based MOF with 2‐methylimidazolate linker (ZIF‐8) is modified and introduced as catalysts in a selective oxidation of alcohol with benzyl alcohol as the model of the reaction. Modification of ZIF‐8 includes the inclusion of Co(II), Cu(II) or Ni(II) ions as partial replacements for the original Zn(II) metal ions during the synthesis process. The resulting modified ZIF‐8 displays similar PXRD patterns to that of ZIF‐8, indicating no alteration of structures after the introduction of Co(II), Cu(II) or Ni(II) ions. However, the addition of Co(II) was found to modify the resulting ZIF‐8 composition to a higher extent compared to that of Cu(II) and Ni(II) ions. The catalytic test of benzyl alcohol oxidation was performed in a solvent‐free condition with TBHP as the oxidant. Reaction optimization includes reaction temperature, mass of catalysts, TBHP concentration, and reaction time. Among all the catalysts employed in the oxidation of benzyl alcohol, Co(II)‐ and Cu(II)‐modified ZIF‐8 show the highest catalytic activity with 64 % and 62 % conversion, respectively. Furthermore, the catalyst leaching and recyclability tests show that the reactions proceed in heterogeneous systems. [ABSTRACT FROM AUTHOR]

Imidazolium salts with complex anions [Co2Li2(Piv)8]2– are formed as undesirable products of the reactions of heterometallic compound [Co2Li2(Piv)6(Py)2] with N-heterocyclic carbenes ItBu and IPr. The study of the magnetic properties of complex (HItBu)2[Co2Li2(µ2-Piv)6(κ1-Piv)2] shows that this compound is a single molecule magnet. Slow magnetic relaxation in the complex occurs due to a combination of the direct and Raman mechanisms. [ABSTRACT FROM AUTHOR]

Two cobalt(II) complexes [CoL1](OTf)2 (1, L1 = 6,6′′-di(anilino)-4′-phenyl-2,2′:6′,2′′-terpyridine) and [CoL2](OTf)2·MeOH (2, L2 = 6,6′′-di(N,N-dimethylamino)-4′-phenyl-2,2′:6′,2′′-terpyridine) were synthesized and characterized. Crystal structure analyses showed that the spin carries were coordinated by five N atoms from the neutral pentaaza ligands, forming distorted trigonal bipyramidal coordination environments. Ab initio calculations revealed large easy-axial anisotropy in complexes 1 and 2. Magnetic measurements suggest that complexes 1 and 2 are field-induced single-molecule magnets, whose relaxations are mainly predominated by Raman and direct processes. [ABSTRACT FROM AUTHOR]

Reacting trimesic acid (H3TMA, C9H6O6) with CaCl2 and MCl2 at 110 °C under hydrothermal conditions gave the isostructural heterobimetallic coordination polymers (CPs) catena‐poly[[tetraaquazinc(II)]‐μ‐5‐carboxybenzene‐1,3‐dicarboxylato‐[tetraaquacalcium(II)]‐μ‐5‐carboxybenzene‐1,3‐dicarboxylato], [CaZn(HTMA)2(H2O)8]n, 1, and catena‐poly[[tetraaquacobalt(II)]‐μ‐5‐carboxybenzene‐1,3‐dicarboxylato‐[tetraaquacalcium(II)]‐μ‐5‐carboxybenzene‐1,3‐dicarboxylato], [CaCo(HTMA)2(H2O)8]n, 2. Compounds 1 and 2 crystallize in the monoclinic space group C2/c. The solid‐state structures consist of eight‐coordinate CaII ions and six‐coordinate MII ions. These ions are connected by a doubly deprotonated HTMA2− ligand to create a one‐dimensional (1D) zigzag chain. Poly[[decaaquabis(μ3‐benzene‐1,3,5‐tricarboxylato)calcium(II)dizinc(II)] dihydrate], {[CaZn2(TMA)2(H2O)10]·2H2O}n, 3, was found incidentally as a minor by‐product during the synthesis of 1 at a temperature of 140 °C. It forms crystals in the orthorhombic space group Ccce. The structure of 3 consists of a two‐dimensional (2D) layer composed of [Zn(TMA)] chains that are interconnected by CaII ions. The presence of aromatic carboxylic acid ligands and water molecules, which can form numerous hydrogen bonds and π–π interactions, increases the stability of the three‐dimensional (3D) supramolecular architecture of these CPs. Compounds 1 and 2 exhibit thermal stability up to 420 °C, as indicated by the thermogravimetric analysis (TGA) curves. The powder X‐ray diffraction (PXRD) data reveal the formation of unidentified phases in methanol and dimethyl sulfoxide, while 1 exhibits chemical stability in a wide range of solvents. The luminescence properties of 1 dispersed in various low molecular weight organic solvents was also examined. The results demonstrate excellent selectivity, sensitivity and recyclability for detecting acetone molecules in aqueous media. Additionally, a possible sensing mechanism is also outlined. [ABSTRACT FROM AUTHOR]

The title coordination polymer, [Co(N3)2(C9H8N2)]n, was synthesized solvothermally. The CoII atom exhibits a distorted octahedral [CoN6] coordination geometry with a bidentate 8-aminoquinoline ligand and four azide ligands. Bridging azide ligands result in chains extending along [100]. N—H...N hydrogen bonds join the chains to give an extended structure with sheets parallel to (002).

Two novel CoII metal–organic frameworks {[Co(BIMB)2(H2O)2](SO4)·EG·3 H2O}n (I) and {[Co(TIMB)2](SiF6)}n (II) were hydrothermally synthesized by corresponding metal salt with organic ligands 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (TIMB) or 1,4-bis((1H-imidazol-1-yl)methyl)benzene (BIMB). Crystal structural analysis reveals that they exhibit varied structures. Compound I contains two crystallographically unique CoII centers, each lying on an inversion center and having a slightly distorted octahedral environment. The BIMB ligands link the CoII cations to generate a three-dimensional porous framework with a 4-connected uninodal (65.8) topology. Compound II exhibits a two-dimensional sheeted metal-organic structure running parallel to the (0 0 1) plane, in which TIMB ligands join Co2+ centers having a six-coordinated octahedral structure. In the solid state, adjacent sheets are further bridged by guest SiF6- anions via C–H...F hydrogen-bonding interactions, giving rise to a three-dimensional supramolecular network structure with a 2-nodal (3-c)2(6-c) net. The topological analysis suggests that the point Schläfli symbol of compound II is (43)2(46.66.83). In addition, their thermal stabilities have also been investigated. [ABSTRACT FROM AUTHOR]

The title compound, [Co(C3H4N2)(C30H30N10)](BF4)2, is a five-coordinate CoII complex based on the neutral ligands tris[(1-benzyltriazol-4-yl)methyl]amine (tbta) and imidazole. It exhibits a distorted trigonal bipyramidal geometry in which the equatorial positions are occupied by the three N-atom donors from the triazole rings of the tripodal tbta ligand. The apical amine N-atom donor of tbta and the N-atom donor of the imidazole ligand occupy the axial positions of the coordination sphere. Two tetrafluoroborate anions provide charge balance in the crystal. [ABSTRACT FROM AUTHOR]

[Mn(SCN)2(2,2′-bipy)2] (1) and [Co(SCN)2(2,2′-bipy)2] (2) were synthesized at ambient temperature by adding aqueous solutions of manganese(II) or cobalt(II) chloride hydrate to aqueous acetonitrile solutions of 2,2′-bipyridine (2,2′-bipy) and potassium thiocyanate. Elemental analyses, FT-IR and UV–vis spectra were used to characterize 1 and 2. Single crystal X-ray diffraction was used to analyze the crystal structures of 1 and 2, revealing that the two are structurally similar. The molecular structures of 1 and 2 consist of Mn or Co ion chelated by two molecules of 2,2′-bipy through four nitrogen atoms and two NCS anions, giving distorted octahedral geometries. The isothiocyanate group is not bridging, instead, two ligands coordinate in a cis arrangement to the manganese or cobalt center by their nitrogen atoms while the sulfur atoms are free. Through hydrogen bonding and π–π stacking interactions, the discrete units of 1 and 2 extend to 3D supramolecular networks with flower and fishbone-like structures. The luminescence behavior of 2,2′-bipy, 1 and 2 were investigated. On HepG2 (liver) and MCF-7 (breast) cancer cells, the anticancer effects of 1 and 2 were evaluated. The activity of 1 and 2 on MCF-7 is more significant than that of HepG2. The IC50 of 1 was lower in HepG2 and MCF-7 cells than for 2. [ABSTRACT FROM AUTHOR]

New macrocyclic Schiff bases, lower rim disubstituted imine derivatives of thia- and calix[4]arenes 7 and 8 adopted in a cone stereoisomeric conformation, bearing two tert-butyl substituents grafted to iminophenol coordinating sites, and containing a spacer composed of two methylene bridges were synthesized. The prepared compounds were characterized by a complex of physicochemical methods in solution (1H/13C NMR spectroscopy, MALDI TOF mass spectrometry) and in the crystalline phase (IR spectroscopy, single-crystal X-ray diffraction (XRD)). In crystals calix[4]arene 7 forms a solvate in which acetonitrile or methanol molecules are included into the macrocycle cavity, whereas the crystals of thiacalix[4]arene 8 contain no solvent molecules. The difference in the conformational behavior of the macrocyclic platform was evidenced when comparing the crystal structures of calix[4]arene 7 and thiacalix[4]arene 8. The stoichiometry and the logarithm and stability constant values of the corresponding complexes of the synthesized macrocyclic Schiff bases with 3d-metal cations (CoII, NiII) in solution were determined using spectrophotometry titration. When interacting with CoII cations, compound 7 forms complexes with stoichiometry Lig: M = 1: 1 and 1: 2 (Lig is ligand, and M is metal). In the case of compound 8, complexes with the stoichiometry Lig: M = 1: 4, as well as 1: 2, are observed, which presumably indicates the involvement of "soft" sulfur atoms in the interaction with the metal cations. The replacement of CoII cations by NiII resulted in the formation in the solution of complexes with the stoichiometry Lig: M = 2: 1, 1: 1 and Lig: M = 1: 1, 1: 2 for compounds 7 and 8, respectively. [ABSTRACT FROM AUTHOR]

The title compound, [Co(C3H4N2)(C30H30N10)](BF4)2, is a five-coordinate CoII complex based on the neutral ligands tris[(1-benzyltriazol-4-yl)methyl]amine (tbta) and imidazole. It exhibits a distorted trigonal bipyramidal geometry in which the equatorial positions are occupied by the three N-atom donors from the triazole rings of the tripodal tbta ligand. The apical amine N-atom donor of tbta and the N-atom donor of the imidazole ligand occupy the axial positions of the coordination sphere. Two tetrafluoroborate anions provide charge balance in the crystal.

Reaction of isoquinoline (iQuin) with cobalt(II) and nickel(II) chloride and bromide produced a family of neutral coordination complexes: (iQuin)2CoX2 [X = Cl (1), Br (2)], (iQuin)4CoX2 (X = Cl (3), X = Br (4)], (iQuin)4NiX2 [X = Cl, (5), X = Br, (6)], and (iQuin)2NiBr2(CH3CN)2 (7). The crystal structures of 1–5 and 7 are reported. The majority of the compounds crystallize with some of the iQuin ligands undergoing a ∼2-fold rotational disorder, likely caused by the nearly equivalent space occupied by the two positions. The disorder is temperature independent and ∼50:50 in all cases but one. Magnetic measurements for all seven compounds indicate that their behavior is dominated by single-ion anisotropy effects with indications of antiferromagnetic exchange also present in 1 and 2. [ABSTRACT FROM AUTHOR]

Two cobalt(II) complexes [CoL1](OTf)2 (1, L1 = 6,6′′-di(anilino)-4′-phenyl-2,2′:6′,2′′-terpyridine) and [CoL2](OTf)2·MeOH (2, L2 = 6,6′′-di(N,N-dimethylamino)-4′-phenyl-2,2′:6′,2′′-terpyridine) were synthesized and characterized. Crystal structure analyses showed that the spin carries were coordinated by five N atoms from the neutral pentaaza ligands, forming distorted trigonal bipyramidal coordination environments. Ab initio calculations revealed large easy-axial anisotropy in complexes 1 and 2. Magnetic measurements suggest that complexes 1 and 2 are field-induced single-molecule magnets, whose relaxations are mainly predominated by Raman and direct processes.

Abstract This work reports a simple and sensitive on-line solid-phase extraction system for the pre-concentration and determination of a trace amount of Co(II (ions by flame atomic absorption spectrometry (FAAS). This method is based on the on-line retention of cobalt ions with polyvinyl chloride modified by 3-(2-thiazolylazo)-2,6-diaminopyridine in a mini-column system. The retained Co(II) ions were eluted with 1.0 mol L−1 HCl, and direct aspiration to flame atomic absorption spectrometry (FAAS) for an accurate determination of it. The important experimental parameters such as the solution pH, length of column (adsorbent mass), sample flow rate, solvent eluent, type and concentration of the eluent, and co-existing ion effects were investigated in detail and optimized. Under the optimum conditions, the calibration graph was linear over the concentration range of 2–150 µg L−1 for pre-concentration of 10.0 mL of the sample solution. The interassay precession (n = 6) was in the range of 1.8–5.2% at the concentration levels of 10.0, 50.0, 100.0, and 140.0 µg L−1. The limit of detection and enhancement factor were 1.3 µg L−1 and 40, respectively. The method was applied for determination of trace levels of Co(II) ions in different real samples such as tap water, waste water, vegetable, fruit, and drug with satisfactory results.

The results of studying the heterometallic trinuclear {Co Ln} and tetranuclear {Co Li2} carboxylate coordination compounds are systematized. The methods of the syntheses are discussed, and the structures and magnetic properties are considered. [ABSTRACT FROM AUTHOR]

The hexacoordinate Co(II) complex [Co(neo)2(cin)][BPh4]·½Me2CO (1·½Me2CO) containing trans-cinnamic acid (Hcin) and neocuproine (neo) was prepared. The compound 1·½Me2CO was characterized via single-crystal X-ray analysis, FT-IR spectroscopy, and magnetic measurements. The coordination polyhedron of the complex cation adopts a deformed octahedron shape, and cinnamate exhibits a bidentate mode of coordination, which is unusual for mononuclear Co(II) cinnamate complexes. The analysis of DC magnetic measurements with zero-field splitting (ZFS) spin Hamiltonian revealed large magnetic anisotropy defined by the axial ZFS parameter D = +53.2 cm−1. AC susceptibility measurements revealed the slow relaxation of magnetization under the applied field; thus, 1·½Me2CO behaves as a field-induced single-molecule magnet. The analysis of magnetic properties was also supported by CASSCF/NEVPT2 calculations. [ABSTRACT FROM AUTHOR]

Four new metal–organic frameworks based on cobalt(II) salts and 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide (odabco) were obtained. Their crystallographic formulae are [Co3(odabco)2(OAc)6] (1, OAc− = acetate), [Co(H2O)2(HCOO)2]·odabco (2), [Co2(H2O)(NO3)(odabco)5](NO3)3·3.65H2O (3), and [Co2(DMF)2(odabco)4](NO3)4·3H2O (4; DMF = N,N-dimethylformamide). Crystal structures of 1–4 were determined by single-crystal X-ray crystallography. Coordination polymer 1 comprises binuclear and mononuclear metal–acetate blocks alternating within uncharged one-dimensional chains, in which odabco acts as a bridging ligand. A layered Co(II) formate 2 contains odabco only as guest molecules located in the interlayer space. Layered compound 3 and three-dimensional 4 have cationic coordination frameworks with 26% and 34% specific void volumes, respectively, unveiling high structural diversity of Co(II)-odabco MOFs based on quite a rare aliphatic moiety. Magnetization measurements were performed for 1, 3, and 4 and the obtained data were interpreted on the basis of their crystal structures. A strong (J/kB~100 K) antiferromagnetic coupling was found within binuclear metal blocks in 1. Ion exchange experiments revealed a considerable iodide uptake by 3 resulting in an up to 75% guest nitrate substitution within the voids of a coordination framework, found by capillary zone electrophoresis data and confirmed by single-crystal XRD. A preservation of 3 crystallinity during the exchange allowed for the guest I− positions within a new adduct with the formula [Co2(H2O)(NO3)(odabco)5]I2(NO3)·1.85H2O (3-I) to be successfully determined and the odabco aliphatic core to be revealed as a main adsorption center for quite large and easily polarizable iodide anions. In summary, this work presents a comprehensive study for a series of 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide-based MOFs of cobalt(II) within the framework of magnetic properties and reports the first example of anion exchange in odabco-based coordination networks, supported by direct X-ray structural data. The reported results unveil promising applications of such frameworks bearing ligands with an aliphatic core in the diverse structural design of selective adsorbents and other types of functional materials. [ABSTRACT FROM AUTHOR]

Heavy metals (HM) are among the most dangerous inorganic ecotoxicants that can have a mutagenic and toxic effect on all objects of the biosphere. Ingressing a living organism, heavy metals can accumulate in various tissues and organs, causing their dysfunction. Therefore, water contamination with heavy metals is among the most urgent problems of environmental safety in both our country and the whole world, and the development of modern, efficient, and cost-effective methods for purifying contaminated water from heavy metals is an essential and urgent task today. Baromembrane separation in combination with other physical and chemical processes is one of the effective methods for extracting heavy metal ions from contaminated waters. In this work, we studied the possibility of using an anionic surfactant sodium dodecyl sulfate (NaSDS) and nonionic polyethylene glycol tert-octylphenyl ether (Triton X-100) to purify contaminated waters from Co(II) by ultrafiltration. The main characteristics of the baromembrane process were determined: the retention factors of the ions of the tested metal and the volumetric flow rate through the polymeric ultrafiltration membrane. Ultrafiltration in combination with the use of surfactants is effective for water purification from heavy metal ions or radionuclides, as demonstrated by an example of Co(II). The process should be performed at concentrations of surfactants near the critical micelle concentration for optimal results. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Education & Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The selective extraction of metals from aqueous solutions is a very important stage in the hydrometallurgical processing of metallic waste. Leach solutions are usually a multicomponent mixture. The main impurity of aqueous solutions obtained after leaching using inorganic acids is iron. In this work, the membrane separation of iron(III) from nickel(II), cobalt(II), and lithium(I) was studied. The facilitated transport of metal ions using polymer inclusion membranes (PIMs) with tetrabutylammonium bromide (TBAB) as an ion carrier under various conditions was analyzed in detail. Several factors, such as the ion carrier concentration in the membrane as well as the effect of the inorganic acid concentration in the source/receiving phases on the kinetic parameters, were investigated. The results show that ionic liquid TBAB is a very selective ion carrier of Fe(III) towards Ni(II), Co(II), and Li(I). [ABSTRACT FROM AUTHOR]

Seven new coordination networks, [Fe(tbbt)3](BF4)2 (1), [Co(tbbt)3](BF4)2 (2), [Fe(tbbt)3](ClO4)2 (3), [Co(tbbt)3](ClO4)2 (4), [Fe(NCS)2(tbbt)2] (5), [Co(NCS)2(tbbt)2] (6), and [Fe(H2O)2(tbbt)2]Br2·2H2O (7), were synthesized with the linker 1,1'-(trans-2-butene-1,4-diyl)bis-1,2,4-triazole (tbbt) and structurally investigated. The structure of complexes 1–4 is composed of three interpenetrating, symmetry-related 3D networks. Each individual 3D network forms a primitive, nearly cubic lattice (pcu) with BF4– or ClO4– anions present in the interstitial spaces. The structure of compounds 5 and 6 is composed of two-dimensional sql layers, which are parallel to each other in the AB stacking type. These layers are interpenetrated by one-dimensional chains, both having the same formula unit, [M(NCS)2(tbbt)2] (M = Fe, Co). The structure of compound 7 consists of parallel, two-dimensional sql layers in the ABCD stacking type. The interpenetration in 1–6 is not controlled by π–π-interactions between the triazole rings or C=C bonds, as could have been expected, but by (triazole)C-H⋯F4B, C-H⋯O4Cl, and C-H⋯SCN anion hydrogen bonds, which suggests a template effect of the respective non-coordinated or coordinated anion for the interpenetration. In 7, the (triazole)C-H⋯Br anion interactions are supplemented by O-H⋯O and O-H⋯Br hydrogen bonds involving the aqua ligand and crystal water molecules. It is evident that the coordinated and non-coordinated anions play an essential role in the formation of the networks and guide the interpenetration. All iron(II) coordination networks are colorless, off-white to yellow-orange, and have the metal ions in the high-spin state down to 77 K. Compound 5 stays in the high spin state even at temperatures down to 10 K. [ABSTRACT FROM AUTHOR]

A friction layer with stability and durability is important to promote the practical application of triboelectric nanogenerators (TENGs). In this work, a two‐dimensional cobalt coordination polymer (Co‐CP) was successfully synthesized using cobalt nitrate, 4,4′,4′′‐tricarboxyltriphenylamine and 2,2′‐bipyridine. To clearly clarify the effect of the doping proportions of Co‐CP and the types of composite polymers on the output performance of the TENG, Co‐CP was combined with two organic polymers having different polarities (polyvinylidene fluoride (PVDF) and ethyl cellulose (EC)) to form a series of composite films, which were used as the friction electrode materials to fabricate TENGs. Electrical characterizations indicated that a high output current and voltage were obtained from the TENG based on 15 wt.% Co‐CP incorporated in PVDF (Co‐CP@PVDF), which could be further improved by the Co‐CP@EC composite film at the same doping ratio. Furthermore, the optimally fabricated TENG was demonstrated to prevent electrochemical corrosion of carbon steel. [ABSTRACT FROM AUTHOR]

Two metal coordination polymers [Ni(oba)(Py2TTz)1.5(H2O)]·2H2O·DMF (1) and [Co(oba)(Py2TTz)(H2O)4]·2H2O (2) have been synthesized under solvothermal conditions [H2oba = 4,4′-oxybis(benzoic acid) and Py2TTz = 2,5-di(pyridine-4-yl)thiazolo[5,4-d]thiazole]. Crystals of compound 1 belong to the orthorhombic system, space group Ibam, with a = 38.928(8), b = 7.7113(14), c = 28.508(6) Å, V = 8558(3) Å3, Z = 8. Compound 2 crystallizes in the monoclinic crystal system, space group C2/c, with a = 33.816(3), b = 6.2697(6), c = 13.5821(13) Å, β = 96.393(3)°, V = 2861.7(5) Å3, Z = 4. The oba2− dianions link two Ni atoms through unidentate carboxylate moieties in a μ1 − η1:η0 coordination mode. Compound 1 features a three-dimensional (3D) framework structure with Py2TTz and oba2− ligands. In compound 2, the central cobalt ion is in an octahedral geometry, which is defined by four oxygen atoms from four different coordinated water molecules and two nitrogen atoms from two different Py2TTz ligands. It is noteworthy that the dicarboxylate ligands oba2− with four oxygen atoms do not directly coordinate with the cobalt ion, and only act as a counter-anion. The luminescence properties of 1 and 2 were also investigated. [ABSTRACT FROM AUTHOR]

The ionic compound [Co(OC5H2N(NO2)2)4]((C2H5)3NH)2 (I) was synthesized by the reaction of CoCl2·6H2O with 2-hydroxy-3,5-dinitropyridine in acetonitrile in the presence of triethylamine as a deprotonating agent. The structure of compound I was studied by X-ray diffraction (CCDC no. 2196071) and thermodynamic characteristics of I were determined. [ABSTRACT FROM AUTHOR]

Two novel acetato complexes with NNN type planar bdmpp ligand, [Ni(OAc)(H2O)2(bdmpp)]OAc (1) and [Co(OAc)(H2O)2(bdmpp)]OAc (2) (bdmpp: 2,6-bis(3,5-dimethylpyrazolyl)pyridine) were synthesized and characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction analysis. Thermal stabilities of these complexes were studied by thermogravimetric and differential thermal analyses. The crystal structures of both complexes were also determined using single-crystal X-ray diffraction. It was found that complexes 1 and 2 possessed smilar octahedral coordination environment in which metal ions were coordinated by N donor atoms of bdmpp, two oxygens of aqua ligands and one oxygen atom from terminal bonding acetato ligand. [ABSTRACT FROM AUTHOR]

NMR spectroscopy was applied to study the temperature dependences of paramagnetic chemical shifts of the [Co(EDTA)]2− complex (1) in D2O solution and in 10% gelatin gel (as a model medium for human or animal tissues). The maximum temperature sensitivity of the chemical shifts d(δexp)/dT was found to be 0.64 ppm K−1 (in 10% gelatin gel). The half-width of the signals of the complex essentially depends on the solution viscosity and temperature, owing to the dipole contribution to the paramagnetic increase in the spin—spin relaxation rate. Complex 1 can be considered as a promising compound for the design of temperature-sensitive NMR probes for determining the local temperature in aqueous media and for advanced diagnosis of diseases using MRI technologies. [ABSTRACT FROM AUTHOR]

A new mixed-valence one-dimensional coordination polymer of formula {[CoII(MeOH)2][(μ-NC)2CoIII(dmphen)(CN)2]2}n·2nH2O (1) was obtained by reacting the Ph4P[CoII(dmphen)(CN)3] metalloligand (dmphen = 2,9-dimethyl-1,10-phenanthroline and Ph4P+ = tetraphenylphosphonium ion) with cobalt(II) acetate tetrahydrate. The structural analysis shows the formation of a neutral 4,2-ribbon-like chain of vertex-sharing cyanido-bridged {CoIII2CoII2} squares in which the metalloligand underwent an oxidation process and a reorganization to form {CoIII(dmphen)(CN)4}− linkers that coordinate to the [CoII(MeOH)2]2+ units through single cyanido ligands. Both cobalt(II) and Co(III) cations are six-coordinated in distorted octahedral environments. The shortest intrachain distance between the paramagnetic cobalt(II) ions is 7.36 Å, a value which is shorter than the shortest interchain one (10.36 Å). Variable-temperature (1.9–300 K) static (dc) magnetic measurements for 1 indicate the occurrence of magnetically isolated high-spin cobalt(II) ions with a D value of +67.0 cm−1. Dynamic alternating current (ac) magnetic measurements between 2.0–13 K reveal that 1 exhibits slow magnetic relaxation under non-zero applied dc fields, being thus a new example of field-induced SIM with easy-plane magnetic anisotropy. Theoretical calculations by CASSCF/NEVPT2 on 1 support the results from magnetometry. The relaxation of the magnetization occurs in the ground state under external dc fields through a two-phonon Raman process and one intra-Kramers mechanism. [ABSTRACT FROM AUTHOR]

The electrochemical sensing potential of two isostructural one-dimensional nickel(II) and cobalt(II) coordination polymers with 4,4′-bipyridine (4,4′-bpy) and 6-oxonicotinate (6-Onic), namely, {[Ni(4,4′-bpy)(H2O)4](6-Onic)2×2H2O}n and {[Co(4,4′-bpy)(H2O)4](6-Onic)2×2H2O}n, was investigated along with the polymers' potential applications in the catalytic oxidation of methanol. The highly oxidative species from redox pairs Ni(II)/Ni(III) and Co(II)/Co(III) in these compounds represent catalytically active centres for oxidation of small molecules. A glassy carbon electrode (GCE) modified with a Ni polymer showed stability and reproducibility in 0.1 M NaOH, while the oxidation current inc 2reased with the increasing methanol concentration, suggesting that the Ni-polymer-modified electrode possess good sensing ability with respect to methanol. The GC electrode modified with the Co polymer is not reproducible and cannot be used for electroanalytical purposes under these experimental conditions. The GC electrode modified with the Ni polymer was successfully applied in the determination of methanol. This method showed favourable linear concentration dependence with a good sensitivity of 2.65 and 11.0 mA mM−1, a wide concentration range (0.001–4 mM), and a detection limit of 0.8 μM, which indicates its excellent application potential for methanol oxidation and thus its determination. [ABSTRACT FROM AUTHOR]

The reaction of hydroxybenzoates with divalent first row transition metal ions afforded four mononuclear complexes, [M(OH2)6](dhbzc)2·2H2O (M = Co2+, 1 or Mn2+, 2), [Ni(OH2)6](hbzc)2·2H2O (3) and [Ni(OH2)5(hbzc)](hbzc)·3H2O (4) (where dhbzc− = 2,6-dihydroxybenzoate and hbzc− = 4-hydroxybenzoate). The complexes were characterized by single crystal and powder X-ray diffraction analyses, infrared spectroscopy, and thermogravimetric analysis. Results showed that the hydrogen bonds present in dhbzc− impaired its coordination to Co2+ and Mn2+. Thereafter, Hirshfeld surface analyses (HS) and 2D fingerprint plots were used to investigate the intermolecular contacts in 1–4. The offset π···π stacking of the dhbzc− counterions in 1 and 2 lead to C···C close contacts over C···H/H···C ones. Complexes 3 and 4 presented the usual herringbone aromatic-based packing for the hbzc− rings with a predominance of C···H/H···C close contacts. The existence of water molecules in the crystal lattices of 1–4 was determined by TG analyses, which proved the presence of coordinated and uncoordinated water molecules. The thermal decomposition patterns were analyzed in light of the percentage of the strongest intermolecular close contacts. [ABSTRACT FROM AUTHOR]

The existence of toxic heavy metals in the aquatic environment has emphasized a considerable exigency to develop several multifunctional biosorbents for their removal. Herein, three individual bacterial species of Cellulosimicrobium cellulans, Bacillus coagulans, and Microbacterium testaceum were successfully isolated from low-level liquid radioactive wastes. Their loading capacities towards cerium and cobalt metal ions were inclusivity inspected under variable operational parameters of pH, primary pollutant concentration, interaction time, temperature, stirring speed, and biosorbent dosage. By analyzing the influence of solution pH, concentration, temperature, biosorbent mass, and agitation speed on the biosorption kinetics, the biosorption process confirms pseudo-second-order kinetic, intraparticle diffusion, and Elovich equation. Remarkably, the isolated Microbacterium testaceum exhibited high loading capacities reaching 68.1 mg g−1, and 49.6 mg g−1 towards Ce(III), and Co(II) ions, respectively, at the initial concentration of 2.8 mM, pH 4.5, and 25 °C. Overall, the isolated bacterial species can potentially be offered up as a promising scavenger for Ce(III) and Co(II) from liquid waste effluents. [ABSTRACT FROM AUTHOR]

The pyrazole-pyridin-2-amine, as a tridentate pyrazole ligand, and its neutral Co(II)/pyrazole complex were prepared using a direct method with a high yield. The desired pyrazole ligand and its complex were subjected to several physicochemical and thermal analyses; moreover, the DFT-like optimization of MEP, HOMO/LUMO, and TD-DFT correlated well with their experimental relatives. Additionally, the oxidation catalytic activities of the Co(II)/pyrazole complex, such as the catecholase of catechol to o-quinone and the phenoxazinone of 2-aminophenol to 2-aminophenoxazinone, were also evaluated under mild RT conditions and atmospheric oxygen. [ABSTRACT FROM AUTHOR]

Potentiometric titration is used to determine constants of stability of cobalt(II) glycylglycinate complexes at a temperature of 298 K and the ionic strength of 0.1 M solutions in aqueous acetone solutions. It is established that in contrast to aqueous solutions, cobalt(II) mono-glycylglycinates, bis-glycylglycinates, and tris-ligand complexes can all form in water–acetone mixtures. The stability of cobalt(II) complexes with glycylglycinate ions grows along with the concentration of acetone in a solution. [ABSTRACT FROM AUTHOR]

Spin crossover (SCO) complexes have been extensively explored as bistable materials and recently used as molecular modules for the development of new multifunctional molecular magnetic materials. Herein, we present the synthesis, crystal structure, magnetic, and electrical properties of a mononuclear cobalt complex constructed by a halogen‐functionalized terpyridine derivative and organosulfonate. A complete and gradual spin transition with the T1/2=200 K was observed for the Co2+ ions through both the magnetic measurement and dynamic crystallographic experiments. Interestingly, considerable room temperature proton conductivity of 6.9×10−5 S cm−1 under 98% relative humidity was evidenced because of the presence of sulfonate‐assisted hydrogen‐bonded proton hopping pathways. The forgoing results not only provide an unprecedented proton‐conducting cobalt(II) SCO complex but also a promising way for the design and construction of bifunctional SCO molecular conductors via the incorporation of SCO transition and proton conduction. [ABSTRACT FROM AUTHOR]

A ditopic nitrogen ligand (E)-N′-(pyridin-4-ylmethylene)isonicotinohydrazide (L) containing both divergent pyridyl coordination sites and a hydrogen-bonding hydrazide–hydrazone moiety was synthesized. The Co(NCS)2-mediated self-assembly of L has resulted in the synthesis of a novel 3-dimensional (3D) supramolecular framework (1) that features both coordination and hydrogen bonding interactions. X-ray structural analysis reveals the formation and coordination mode of 1 in the solid state. The rational utilization of coordination bonds and hydrogen bonding interactions is confirmed and responsible for constructing the 3D materials. Catalytic studies using 1 in the presence of an activator are performed for the hydroboration and hydrosilylation reactions of ketones and aldehydes, and the results are compared with previously reported cobalt-based polymeric catalysts.

The synthesis of ionic complexes of cadmium(II) chloride and cobalt(II) chloride with N,N'-diethylthiourea (detu) ligands has not been previously reported. Therefore, in this research, the synthesis was carried out to study the structure and characterization of the two ionic complex compounds. The cadmium(II)-detu ionic complex was synthesized using the direct reaction method with a ratio between Cd(II) salt and detu ligand of 1:2. Meanwhile, the cobalt(II)-detu ionic complex was synthesized with a ratio between Co(II) salt and detu ligand of 2:4. The cadmium(II)-detu and cobalt(II)-detu ionic complexes have melting points of 105-108 ˚C and 122-125 ˚C, respectively. The electrical conductivity of the cadmium(II)-detu and cobalt(II)-detu complexes showed that the complexes were ionic. The FTIR analysis showed the shifting of the C=S functional group’s band to the smaller wavenumber, which indicates the coordinating detu ligand to the cadmium(II) and cobalt(II) through the S atom. The indirect evidence from 1H-NMR showed that CH3 and CH2 only slightly shifted between the free detu ligand and the Cd-detu and Co-detu complexes.

A novel ladder-chain cobalt(II) coordination polymer, {[Co3(C7H4ClO2)6(C10H8N2)4(H2O)2]·2CH3OH}n, was synthesized and characterized. The structure contains two CoII centres with different octahedral environments, [Co(1)N3O3] and [Co(2)N2O4]. The O-donating 3-chlorobenzoate anions (3-Clbenz) act as the terminal ligands, while the N-donating 4,4′-bipy molecules play the role of linkers. The Co(1) ions are linked by 4,4′-bipy molecules into linear chains. Two such chains are joined by [Co(2)(3-Clbenz)2(H2O)2] units via two 4,4′-bipy bridging ligands, thus forming the ladder-chain structure. The crystal packing of the title compound is stabilized by supramolecular interactions, such as hydrogen bonding, π–π and halogen...π contacts, giving a three-dimensional framework. The spectroscopic and thermal properties of the title compound have also been investigated.

• A series of novel 2,6-bis(pyrazol-1-yl)pyridine Cobalt complexes have been synthesized and applied to catalyze the highly selective hydroboronation of alkenes. • These catalysts function effectively under mild, solvent-free conditions, demonstrating contrasting selectivities: Markovnikov-type selectivity for vinylarenes and anti -Markovnikov-type selectivity for alkyl alkenes. A novel series of cobalt (II) catalysts featuring 2,6-bis(pyrazol-1-yl)pyridine ligands have been synthesized for the purpose of achieving high selectivity in hydroboration reactions of alkenes. These catalysts function effectively under mild, solvent-free conditions, demonstrating contrasting selectivities: Markovnikov-type selectivity for vinylarenes and anti -Markovnikov-type selectivity for alkyl alkenes. This dual-selectivity system offers a versatile platform for the controlled hydroboration of a diverse range of alkene substrates. [Display omitted] [ABSTRACT FROM AUTHOR]

The in situ reaction of the terminal amine groups in the mononuclear cobalt(II) complex with acetone leads to imine bond formation and the construction of a one-dimensional coordination polymer. [Display omitted] • A methodology utilised to form COFs was successfully employed to construct a MOF. • A cobalt(II) chlorido complex ligated by pyrazole with an amine substituent was characterised. • The in situ construction of a coordination polymer after reaction with acetone was demonstrated. • The coordinated pyrazole amine was easily reacted with a carbonyl group to form an imine bond. An outline of the in situ construction of a coordination polymer by reacting a mononuclear cobalt(II) complex, functionalised with an amine substituent, with acetone is given. The methodology involved 4-amino-3,5-diisopropyl-1-pyrazole (denoted as L1pzHNH 2) as the precursor, putative linker molecule. Reaction of the ligand with anhydrous cobalt(II) chloride, yielded a four-coordinated cobalt(II) chlorido complex, [CoCl 2 (L1pzHNH 2) 2 ]. When the complex was reacted with acetone, a four-coordinated cobalt(II) chlorido coordination polymer, [CoCl 2 {L1pzHN=C(CH 3) 2 }] n , with an imine bond, was obtained. The complexes were characterised by various spectroscopic techniques. X-ray crystallography shows [CoCl 2 (L1pzHNH 2) 2 ]·2(thf) to comprise a tetrahedrally coordinated cobalt(II) centre with the donors being two chlorido and two pyrazolyl-N atoms. Similarly, [CoCl 2 {L1pzHN=C(CH 3) 2 }] n features a Cl 2 N 2 donor set defining an approximately tetrahedral geometry with the imine-N donors being derived from a pyrazolyl ring and a symmetry related exocyclic imine-N atom with the result that a one-dimensional coordination polymer with a helical topology is formed. When the uncoordinated precursor molecule, L1pzHNH 2 , was reacted with acetone, the formation of the imine was confirmed by 1H NMR measured in (CD 3) 2 CO solution. However, from the 1H NMR measured for the imine in CDCl 3 solution, a 70:30 equilibrium between the imine and amine was established. It is concluded that the nucleophilicity of the amine group is enhanced by the binding of cobalt(II) to the pyrazole nitrogen in [CoCl 2 (L1pzHNH 2) 2 ]·2(thf), thereby favouring irreversible imine formation. The facile formation of [CoCl 2 {L1pzHN=C(CH 3) 2 }] n in the solid-state also correlates with the reduced solubility of the coordination polymer structure in organic solvents. [ABSTRACT FROM AUTHOR]

[Display omitted] New six-coordinated N -propargylimidazole complexes with cobalt(II), nickel(II) and copper(II) chlorides, [M(N -propargylimidazole) 4 Cl 2 ], were obtained in good yields by the reaction of N -propargylimidazole with corresponding metal chlorides. Molecular and crystal structures of compounds 1 – 3 were studied by X-ray analysis. Numerous non-covalent interactions including halogen bonds and π-stacking forms in the crystal were analyzed in the framework of quantum theory Atom in molecules. An evaluation of the antimicrobial activity of N -propargylimidazole complexes with Co(II), Ni(II) and Cu(II) chlorides in relation to E. durans , B. subtilis and E. coli showed that the complexes of nickel exhibit antimicrobial activity comparable to gentamicin in relation to E. coli. To explore the inhibitory activity mechanism the molecular docking was carry out. [ABSTRACT FROM AUTHOR]