Use of Complexation TLC to Investigate Selected Monosulfides. Part I. Silica Impregnated with Cu(II), Co(II), Ni(II), Mn(II), Al(III), Cr(III), and Fe(III) Cations as Stationary Phase

JPC – Journal of Planar Chromatography – Modern TLC - This paper focuses on the use of complexation liquid chromatography (in its TLC mode) to investigate eleven monosulfides. In the...     

Comparison of Different PLS Algorithms for Simultaneous Determination of Cd(II), Cu(II), Pb(II), and Zn(II) by Anodic Stripping Voltammetry at Bismuth Film Electrode

In this work we evaluated the use of different variable selection techniques combined with partial least‐squares regression (PLS) – genetic algorithm PLS (GA‐PLS), interval PLS (iPLS), and synergy interval PLS (siPLS) – in the simultaneous determination of Cd(II), Cu(II), Pb(II) and Zn(II) by anodic stripping voltammetry at a bismuth film. Generally, variable selection provided an improvement in prediction results when compared to full‐voltammogram PLS. The use of interval selection based algorithms have shown to be most adequate than the selection of discrete variables by GA. Excellent analytical performances were obtained despite the inherent complexity of the simultaneous determination.     

Biocatalysis,DNA–protein interactions,cytotoxicity and molecular docking of Cu(II), Ni(II), Zn(II) and V(IV) Schiff base complexes

Four mononuclear metal complexes (Cu(II) ( 1 ), Ni(II) ( 2 ), Zn(II) ( 3 ) and V(IV) ( 4 )) were synthesized using the Schiff base ligand 2,2′‐{cyclohexane‐1,2‐diylbis[nitrilo(1E )eth‐1‐yl‐1‐ylidine]}bis[5‐(prop‐2‐yn‐1‐yloxy)phenol] and structurally characterized by various spectral techniques. The catecholase‐mimicking activities of 1 – 4 were investigated and the results reveal that all the complexes have ability to oxidize 3,5‐di‐tert ‐butylcatechol (3,5‐DTBC) to 3,5‐di‐tert ‐butylquinone in aerobic conditions. Electrospray ionization mass spectrometry studies were performed for 1 – 4 in the presence of 3,5‐DTBC to determine the possible complex–substrate intermediates. X‐band electron paramagnetic resonance spectroscopy results indicate that the metal centres are involved in the catecholase activity. Ligand‐centred radical generation was further confirmed by density functional theory calculation. The phosphatase‐like activity of 1 – 4 was investigated using 4‐nitrophenylphosphate as a model substrate. All the complexes exhibit excellent phosphatase activity in acetonitrile medium. The interactions of 1 – 4 with calf thymus DNA (CT‐DNA) and bovine serum albumin (BSA) protein were investigated using absorption and fluorescence titration methods. All the complexes strongly interact with CT‐DNA and BSA protein. The complexes exhibit significant hydrolytic cleavage of supercoiled pUC19 DNA. Complexes 1 – 4 exhibit significant in vitro cytotoxicity against MCF7 (human breast cancer) and MIA‐PA‐CA‐2 (human pancreatic cancer) cell lines. Moreover, the molecular docking technique was employed to determine the binding affinity with DNA and protein molecules.     

Synthesis,Structural, Biological Evaluation,Molecular Docking and DFT Studies of Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) Complexes bearing Heterocyclic Thiosemicarbazone ligand

A new ligand, 2‐aminonicotinaldehyde N‐methyl thiosemicarbazone (ANMTSC) and its metal complexes [Co(II) ( 1 ); Ni(II) ( 2 ); Cu(II) ( 3 ); Zn(II) ( 4 ); Cd(II) ( 5 ) or Hg(II) ( 6 )] were synthesized. The compounds were characterized by analytical methods and various spectroscopic (infrared, magnetic, thermal, ¹H, ¹³C NMR, electronic and ESR) tools. The structure of ANMTSC ligand was confirmed by single crystal X‐ray diffraction study. The spectral data of metal complexes indicate that the ligand acts as mononegative, bidentate coordination through imine nitrogen (N) and thiocarbonyl sulphur (S^?) atoms. The proposed geometries for complexes were octahedral ( 1 – 2 ), distorted octahedral ( 3 ) and tetrahedral ( 4 – 6 ). Computational details of theoretical calculations (DFT) of complexes have been discussed. The compounds were subjected to antimicrobial, antioxidant, antidiabetic, anticancer, ROS, studies and EGFR targeting molecular docking analysis. Complex 5 has shown excellent antibacterial activity and the complexes 2 and 5 have shown good antifungal activity. The complexes 1 and 4 displayed good antioxidant property with IC₅₀ values of 11.17 ± 1.92 μM and 10.79 ± 1.85 μM, respectively compared to standard. In addition, in vitro anticancer activity of the compounds was investigated against HeLa, MCF‐7, A549, IMR‐32 and HEK 293 cell lines. Among all the compounds, complex 4 was more effective against HeLa (IC₅₀ = 10.28 ± 0.69 μM), MCF‐7 (IC₅₀ = 9.80 ± 0.83 μM), A549 (IC₅₀ = 11.08 ± 0.57 μM) and IMR‐32 (10.41 ± 0.60 μM) exhibited superior anticancer activity [IC₅₀ = 9.80 ± 0.83 ( 4 ) and 9.91 ± 0.37 μM ( 1 )] against MCF‐7 compared with other complexes.     

Magnesium(II), Calcium(II), and Barium(II) Coordination Compounds Constructed by 1H‐Tetrazolate‐5‐acetic Acid Ligand

Reactions of H₂tza (H₂tza = 1H‐tetrazolate‐5‐acetic acid) with Mg(NO₃)₂ · 6H₂O, Ca(NO₃)₂ · 4H₂O, or Ba(NO₃)₂ with the presence of KOH under hydrothermal conditions, produced three new coordination compounds, [M(tza)(H₂O)₂] (M = Mg ( 1 ), Ca ( 2 ), Ba ( 3 )). These compounds were structurally characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. Compounds 1 and 3 display 2D structures, whereas 2 reveals a 1D structure with bridging tza ligand molecules as linkers. Furthermore, the luminescence properties of 1 – 3 at room temperature in the solid state were also investigated. The results show that the nature of metal ions play an important role in governing the molecular frameworks of 1 – 3 , and the strong coordinate abilities of carboxylate and tetrazolate group, endow tza with abundant coordination modes.     

Thin-Layer Chromatography of Anions — Separation of Coexisting Hexacyanoferrate(II), Hexacyanoferrate(III) and Thiocyanate with a New Mobile Phase

JPC – Journal of Planar Chromatography – Modern TLC - The thin-layer chromatography of eighteen anions has been performed on silica layers with mixed aqueous–organic mobile...     

Nickel(II), Cadmium(II), and Copper(II) Complexes Based on Ditopic Terpyridine Derivative Ligand: Syntheses,Crystal Structures,and Luminescent Properties

Three complexes with the ditopic ligand 4′‐[4‐(quinolin‐8‐yloxymethyl)phenyl]‐2,2′:6′,2′′‐terpyridine (abbreviated as L ), [Ni(L)₂](CH₃COO)₂ ( 1 ), [Cd(L)₂](ClO₄)₂ ( 2 ), and [Cu₂(L)₂](ClO₄)₄ · 4DMF ( 3 ), were synthesized and characterized by elemental analysis, IR spectroscopy, and structurally analyzed by X‐ray single‐crystal diffraction. Interestingly, in complexes 1 and 2 , two ligands adopt a tridentate chelating pattern where the oxaquinoline group is non‐coordinated and coordinate with one M^II ion (M = Ni for 1 , M = Cd for 2 ) to form a mononuclear unit. In complex 3 , two ligands bridge two Cu^II ions by pyridyl N atoms, ethereal O atoms, and quinolyl N atoms in a head‐to‐tail mode to generate a dinuclear [Cu₂L₂] unit. Moreover, extended 1D and 2D supramolecular architectures are further constructed in 1 – 3 by multiple secondary interactions such as aromatic stacking and hydrogen bonding. Notably, the structural diversity of complexes 1 – 3 can be properly assigned to the central metal ions that have distinct coordination preferences. In addition, luminescent properties of the ligand and complex 2 were also investigated.     

Cytotoxic dimeric half-sandwich Ru(II), Os(II) and Ir(III) complexes containing the 4,4′-biphenyl-based bridging ligands

A series of dinuclear half-sandwich Ru(II), Os(II) and Ir(III) complexes [Ru₂(μ-Lⁿ)(η⁶-pcym)₂Cl₂](PF₆)₂ ( 1 , 4 ), [Os₂(μ-Lⁿ)(η⁶-pcym)₂Cl₂](PF₆)₂ ( 2 , 5 ) and [Ir₂(μ-Lⁿ)(η⁵-Cp*)₂Cl₂](PF₆)₂ ( 3 , 6 ), based on 4,4′-biphenyl-based bridging Schiff base ligands N,N′-(biphenyl-4,4′-diyldimethylidyne)bis-2-(pyridin-2-yl)methanamine (L¹; for 1 – 3 ) and N,N′-(biphenyl-4,4′-diyldimethylidyne)bis-2-(pyridin-2-yl)ethanamine (L²; for 4 – 6 ) is reported; pcym = 1-methyl-4-(propan-2-yl)benzene, Cp* = pentamethylcyclopentadienyl. The complexes were characterized by relevant analytical techniques (i.e. elemental analysis, FT-IR, NMR, ESI-MS), and their in vitro cytotoxicity was assessed at six cancerous and two non-cancerous (healthy) human cell lines. Overall, complexes 4 – 6 , containing the L² bridging ligand, revealed higher cytotoxicity as compared with 1 – 3 and, thus, they were studied in greater detail. The best-performing complex 6 exceeded at least twice the in vitro cytotoxicity of cisplatin and showed high selectivity towards the cancer cells over the normal ones, including the primary culture of human hepatocytes. In contrast to cisplatin, complexes 4 – 6 did not induce the cell cycle modification of the treated A2780 human ovarian carcinoma cells (studied by flow cytometry and Western blot analysis). High levels of superoxide anion were induced by complexes 4 – 6 at the A2780 cells. The levels of activated forms of Caspase-3 and Caspase-8 at the A2780 cells treated by Ru(II) complex 4 were comparable with cisplatin, while complexes 5 and 6 had only a minor effect on activation of these caspases.     

Determination of Lead(II), Copper(II), Zinc(II), Cobalt(II), Cadmium(II), Iron(III), Mercury(II) using sequential injection extractions

Sequential injection analysis is still dominated by single component analysis. In this proposed robust, economical simple instrumental system seven different metal ions are determined simultaneously using thin-film sequential injection extraction (SIE) with multivariate calibration and multiwavelength detection. Dithizone, in ethanol, is used as extractant and the metal dithizonates’ spectra are generated by a diode array spectrophotometer between 300 and 700 nm. The SI thin-film extraction using water miscible with ethanol works due to the hydrophobic interaction of ethanol with the Teflon wall to create a thin film. A sample frequency of 27 samples per hour was obtained with a sample carry-over of less than 1%. The results of the proposed sequential injection extraction system compare favourably with the results obtained by using standard atomic absorption spectrometry (AAS) methods on conventional extraction samples.     

Oxygen Plask-TLC Microdetermination of Binary and Ternary Mixtures of Hg(II), Cu(II) and Cd in their Organic Compounds and Some Pharmaceutical Preparations

Abstract

Binary and ternary mixtures of the organic compounds of the title elements are decomposed either by wet digestion in the Kjeldahl flasks or through combustion in the oxygen flask using 1:1 HNO₃ soln. as absorbent and Pt gauze as sample holder. An aliquot of 15 μl of each decomposed mixture is separated on thin layer plate, using silica gel (G 60) as stationary phase and a mixture of 100 ml benzene: 80 ml acetone : 20 ml DMF as a mobile phase in normal saturation system at 25°C. The spots areas are determined, from which the individual concentrations of the cations are calculated. Parallely the spots are scratched from the plates and are eluted with water. Their concentrations are measured in the UV-region, for Hg(II) at 205 nm, for Cu(II) at 203 and for Cd at 201 nm. Concentrations are obtained from previously constructed calibration curves which are linear for Hg(II) in the range 0.0 – 0.375 ppm, for Cu(II) in the range 0.0 – 3.811 ppm and for Cd from 0.7 – 13.48 ppm.     

Synthesis and chemical characterization of biologically important complexes of vanillin thiosemicarbazone with manganese(II), iron(II), cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), and mercury(II)

Summary Vanillin thiosemicarbazone (VTSC) has been used to isolate the complexes of the types [M(VTSC)₂(H₂O)₂]X₂ (M=Mn^II, Fe^II, Co^II, or Ni^II and X=Cl) and [M(VTSC)X₂]H₂O (M=Cu^II, Zn^II, Cd^II or Hg^II and X=Cl). Probable structures of these complexes are suggested on the basis of elemental analysis, molar conductance, magnetic moment and electronic and i.r. spectral data. The fungicidal activity of VTSC and the isolated complexes has been evaluated on pathogenic fungi,Alternaria (Sp.),Paecilomyces (Sp.) andPestalotia (Sp.).On leave from the University of Myosore.     

Spectrometric Studies on the Complexation of Pd(II), Fe(III) and Pt(IV) with mandelazo I

Abstract

A spectrometric study of the reaction between Pd(II), Fe(III) and Pt(IV) ions, and Mandelazo I was carried out. The optimum conditions favouring the formation of the complexes are extensively investigated. The stoichiometry of the complexes formed in solution (1:2, 1:1, 1:1), their apparent stability constants (5.45 × 10⁹, 2.39 × 10⁶, 4.12 × 10⁵) and the ranges for obedience to beer's law (0.2 – 6.4, 0.25 – 7.0, 1.5 – 42.0 μg/mL) are reported for Pd(II), Fe(III) and Pt(IV), respectively. The effect of some metal ions including Cu(II), Zn(II), Mn(II), Cd(II), Hg(II), Co(II), Ni(II), Be(II), Al(III), Th(IV) and U(VI), on the maximum absorbance of the formed complexes was also investigated.     

Formation of Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I) and Cd(II) hexacyanocobaltates

A study is reported of the formation of Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I) and Cd(II) hexacyanocobaltates. The results show that the precipitates form by reaction of the metal ions with KCo(CN)(6)(2-) ion-pairs in 1:1 ratio, followed by solid phase transformations.     

Adsorption of Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Fe(II), and As(V) on bacterially produced metal sulfides

The adsorption of Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Fe(II) and As(V) onto bacterially produced metal sulfide (BPMS) material was investigated using a batch equilibrium method. It was found that the sulfide material had adsorptive properties comparable with those of other adsorbents with respect to the specific uptake of a range of metals and, the levels to which dissolved metal concentrations in solution can be reduced. The percentage of adsorption increased with increasing pH and adsorbent dose, but decreased with increasing initial dissolved metal concentration. The pH of the solution was the most important parameter controlling adsorption of Cd(II), Cu(II), Fe(II), Ni(II), Pb(II), Zn(II), and As(V) by BPMS. The adsorption data were successfully modeled using the Langmuir adsorption isotherm. Desorption experiments showed that the reversibility of adsorption was low, suggesting high-affinity adsorption governed by chemisorption. The mechanism of adsorption for the divalent metals was thought to be the formation of strong, inner-sphere complexes involving surface hydroxyl groups. However, the mechanism for the adsorption of As(V) by BPMS appears to be distinct from that of surface hydroxyl exchange. These results have important implications to the management of metal sulfide sludge produced by bacterial sulfate reduction.     

Organic acid solutions in the chromatography of inorganic ions. VII. Cation exchange of Mg(II), Ca(II), Sr(II), Ba(II), Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II) and Fe(III) in succinate media

Summary The cation-exchange behaviour of Mg(II), Ca(II), Sr(II), Ba(II), Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II) and Fe(III) in succinate media at various concentrations and pH, was studied with Dowex 50 WX8 resin (200–400 mesh) in the NH ₄ ⁺ form. As examples separations of Cd(II)/Co(II), Cd (II)/Ni(II), Fe(III)/Cu(II)/Ni(II) and Mg(II)/Ca(II)/Sr(II)/Ba(II) have been achieved.This work was supported by C.N.R. of Italy.     

Complexation of managanese(II), cobalt(II), nickel(II), zink(II), and cadmium(II) cations with amoxicillin

The interaction of amoxicillin anions (Axn^?) with Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺, and Cd²⁺ in aqueous solution at 20°C and an ionic strength of 0.1 (KNO₃) has been studied pH-metrically. In a neutral and weak alkaline solution, MAxn⁺ and M(OH)Axn complexes are formed. The formation constants and the pH ranges of existence of these complexes have been determined.     

N-benzamidosalicylaldimine complexes of copper(II), nickel(II), cobalt(II), iron(II), manganese(II), oxyvanadium(IV) and oxytitanium(IV)

Summary N-benzamidosalicylaldimine (H₂L) complexes of Cu^II, Ni^II, Co^II, Fe^II, Mn^II. VO_IV and TiO_IV have been prepared. The ligand probably coordinates to the metal from the hydroxyl, carbonyl and imino groups.     

Reaction of cefalexine with manganese(II), cobalt(II), nickel(II), zinc(II), and cadmium(II) ions

The reaction of cefalexine anions (Cpx^?) with Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺, and Cd²⁺ ions in aqueous solution at 20°C and ionic strength 0.1 was studied by pH-metry. In weakly alkaline medium, unstable complexes MCpx⁺ and M(OH)Cpx are formed, in which Cpx^? behaves as a monodentate lidand coordinated through the amino group.     

Complexation of copper(II), nickel(II), cobalt(II), zinc(II), and manganese(II) chlorides with acylated polyethylenepolyamines

Complexation of some non-ferrous metals with acylated polyethylenepolyamines in 90% aqueous ethanol has been studied by pH-metric titration and visible absorption spectroscopy. The composition and stability constants of complexes have been determined.     

Chelated complexes of cadmium(II), cobalt(II), copper(II), mercury(II), nickel(II), uranyl(II) and zinc(II) with benzil bis(4-phenylthiosemicarbazone)

Summary Complexes of Co^II, Ni^II, Cu^II, Zn^II, Cd^II, Hg^II and UO ₂ ^II with benzil bis(4-phenylthiosemicarbazone), H₂BPT, have been synthesized and their structures assigned based on elemental analysis, molar conductivity, magnetic susceptibility and spectroscopic measurements. The i.r. spectra suggest that the ligand behaves as a binegative quadridentate (NSSN) (Co^II, Cu^II, Hg^II and UO ₂ ^II complexes) or as a binegative quadridentate-neutral bidentate chelating agent (Ni^II, Zn^II and Cd^II complexes). Octahedral structures for the Co^II and Ni^II complexes and square-planar structure for the Cu^II complex are suggested on the basis of magnetic and spectral evidence. The crystal field parameters (Dq, B and _B) for the Co^II complex are calculated and agree fairly well with the values reported for known octahedral complexes. The ligand can be used for the microdetermination of Ni^II ions of concentration in the 0.4–6×10^–4 mol l^–1 range and the apparent formation constant for the species generated in solution has also been calculated.