Orotic acid complexes of Co(II), Ni(II), Zn(II) and Cd(II) with imidazole

The [Co(HOr)(H₂O)₂(im)₂] (1), [Ni(HOr)(H₂O)₂(im)₂] (2), [Zn(H₂O)₂(im)₄](H₂Or)₂ (3) and [Cd(HOr)(H₂O)(im)₃] (4) complexes (H₃Or: orotic acid, im: imidazole) were synthesized and characterized by elemental analysis, magnetic and conductance measurements, UV-vis and IR spectra. The thermal behaviour of the complexes was also studied by simultaneous thermal analysis techniques (TG, DTG and DTA). The orotate ligand (HOr²⁻) coordinated to the Co(II), Ni(II) and Cd(II) ions are chelated to the deprotonated pyrimidine nitrogen (N₍₃₎) and the carboxylate oxygen, while do not coordinate to the Zn(II) ion is present as a counter-ion (H₂Or⁻). The first thermal decomposition process of all the complexes is endothermic deaquation. This stage is followed by partially (or completely) decomposition of the imidazole and orotate ligands. In the later stage, the remained organic residue exothermically burns. On the basis of the first DTG_max, the thermal stability of the complexes follows order: 2, 176°C>1, 162°C>4, 155°C>3, 117°C in static air atmosphere. The final decomposition products which identified by IR spectroscopy were the corresponding metal oxides.     

Synthesis, spectral and thermal studies of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complex dyes based on hydroxyquinoline moiety

A series of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of azo-compounds containing hydroxyl quinoline moiety have been synthesized and characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic and ESR spectral studies. The results revealed the formation of 1:1 and 1:2 (L:M) complexes. The molar conductance data reveal that the chelates are nonelectrolyte. IR spectra indicate that the azodyes behave as monobasic bidentate or dibasic tetradentate ligands through phenolate or carboxy oxygen, azo N for 1:1 (L:M) complexes beside phenolate oxygen and quinoline N atoms for 1:2 (L:M) complexes. The thermal analyses (TG and DTA) as well as the solid electrical conductivity measurements are also studied. The molecular parameters of the ligands and their metal complexes have been calculated.     

Synthesis and characterization of Co(II), Ni(II), Zn(II) and Cu(II) complexes with a new tetraazamacrocyclic Schiff base ligand containing a piperazine moiety: X-ray crystal structure determination of the Co(II) complex

Two macrocyclic Schiff base ligands, L¹ [1+1] and L² [2+2], have been obtained in a one-pot cyclocondensation of 1,4-bis(2-formylphenyl)piperazine and 1,3-diaminopropane. Unfortunately, because of the low solubility of both ligands, their separation was unsuccessful. In the direct reaction of these mixed ligands (L¹ and L²) and the appropriate metal ions only [CoL¹(NO₃)]ClO₄, [NiL¹](ClO₄)₂, [CuL¹](ClO₄)₂ and [ZnL¹(NO₃)]ClO₄ complexes have been isolated. All the complexes were characterized by elemental analyses, IR, FAB-MS, conductivity measurements and in the case of the [ZnL¹(NO₃)]ClO₄ complex with NMR spectroscopy.     

Study of protonation and Zn(II), Cd(II), Cu(II) and Mn(II) complexation with a glutamic acid N-pyrimidine derivative: Crystal structure of a neutral Cd(II) complex of the bianionic ligand

The compound N-(4-amino-1-methyl-5-nitroso-6-oxo-1,6-dihydropyrimidin-2-yl)-(s)-glutamic acid (H₃L) was synthesised and structurally characterised by analytical methods and ¹H, ¹³C and ¹⁵N NMR spectroscopy. This compound (H₃L) shows the same topology as other model receptors previously used to develop chemical functionalization at the surface of an active carbon when they adsorb on it. Protonation of H₃L and its coordination ability towards Cd²⁺, Zn²⁺, Cu²⁺ and Mn²⁺ ions in water solution was also studied by potentiometric methods, UV–Vis and ¹H, ¹³C NMR spectroscopies. The obtained results allow us to fit the operative conditions for the use of the activated carbon–H₃L adsorbent for the retaining of the above-mentioned metal ions in aqueous solutions. The molecular structure of {[Cd(HL)H₂O] · 3H₂O}_n was solved by single-crystal X-ray diffraction methods.     

Synthesis and Characterization of Ni(II), Cu(II), Zn(II) and Cd(II) Complexes of a New Vic-Dioxime Ligand

In this study, 1,2-dihydroxyimino-3,7-di-aza-9,10-O-α-methyl benzal decane (LH₂) was synthesized starting from 1,2-O-α-methyl benzal-4-aza-7-amino heptane (RNH₂) and antichloroglyoxime. With this ligand, complexes were synthesized using Ni(II) and Cu(II) salts with a metal:ligand ratio of 1:2. However, the reaction of the ligand with salts of Zn(II) and Cd(II) gave products with metal:ligand ratio of 1:1. Structures of the ligand and its complexes are proposed based on elemental analyses, IR, ¹³C- and ¹H-NMR spectra, magnetic susceptibility measurements and thermogravimetric analyses (TGA).     

Core-modified porphyrin incorporating a phenolate donor. Characterization of Pd(II), Ni(II), Zn(II), Cd(II), and Fe(III) complexes

Coordinating properties of acetoxybenziporphyrin, (TPBPOAc)H, have been investigated for a number of metal ions. Insertion of Ni, Pd, and Fe results in the cleavage of the acetoxy group leading to complexes (TPBPO)Ni(II), (TPBPO)Pd(II), and (TPBPO)Fe(III)X containing a M-O bond. No cleavage is observed with Zn(II) and Cd(II), which form complexes (TPBPOAc)M(II)Cl, where M = Zn, Cd. (TPBPO)Ni(II) can also be obtained from the dication of hydroxybenziporphyrin, [(TPBPOH)H(3)]Cl(2), which is prepared by acid hydrolysis of the acetoxy compound. The diamagnetic (TPBPO)Ni(II) can be transformed into the paramagnetic (TPBPOAc)Ni(II)Cl in a reaction with acetyl chloride. X-ray structures have been determined for (TPBPO)Pd(II) and (TPBPOAc)Zn(II)Cl. In the palladium species, the phenolate moiety forms a strong bond to the Pd ion and an unusual interaction geometry is observed, enforced by the macrocyclic environment. Association of a TFA molecule to the phenolic oxygen does not cause significant structural changes in the (TPBPO)Pd(II) molecule. In (TPBPOAc)Zn(II)Cl, the metal ion weakly interacts with the phenolic fragment. The paramagnetic Fe(III) complexes, (TPBPO)Fe(III)X, have been investigated with (1)H NMR spectroscopy. The observed spectral patterns are consistent with the presence of a high-spin Fe(III) center and pi delocalization of spin density onto the phenoxide fragment. Each of the compounds (TPBPO)Fe(III)X exists in solution as a mixture of two isomers, which for X = I are shown to remain in a temperature-dependent equilibrium. The observed isomerism results from two nonequivalent orientations of the axial halide with respect to the puckered macrocyclic ring.     

Foam fractionation of cyanide complex anions of Zn(II), Cd(II), Hg(II) and Au(III)

An experimental investigation is presented of the batch foam fractionation of the cyanide complex anions of Zn(II), Cd(II), Hg(II) and Au(III) from 1.0 × 10⁻⁵ M (metal concentration) alkaline aqueous solutions, with the cationic surfactant hexadecyltrimethylammonium chloride. The effects are established of the presence of CN⁻ over the concentration range 2.5 × 10⁻⁵M−1.0 M, of the presence of NO₃⁻ over the concentration range 0.05–0.75 M, and of interferences to metal foam fractionation provided by 0.50 M concentrations of NO₃⁻, Br⁻, CN⁻, Cl⁻ or SO₄²⁻. Results are discussed in terms of the complex cyanide species of each metal that may have been present and in terms of the extent of hydration of the complex cyanide anions and of the potentially-interfering simple anions. The selectivity sequence, Au(CN)₄⁻Hg(CN)₄²⁻Cd(CN)₄²⁻Zn(CN)₄²⁻ is established, both from data for single-metal solutions and for solutions containing equimolar concentrations of all four metals. A partial separation of the metals can be achieved in the presence of high concentrations of NO₃⁻, which can be improved by taking maximum advantage of flotation rate differences.     

Architectural formation of a conjugated bimetallic Pd(II) complex via oxidative complexation and a tetracyclic Pd(II) complex via self-assembling complexation

The conjugated homobimetallic palladium(II) complex [(L1)Pd(qd)Pd(L1)] (qd = quinonediimine) was obtained in a one-pot reaction by the in-situ oxidative complexation of 1,4-phenylenediamine with the palladium(II) complex [(L1)Pd(MeCN)] (H2L1 = N,N'-bis(2-phenylethyl)-2,6-pyridinedicarboxamide) while in the absence of an additional ligand [(L1)Pd(MeCN)] was converted to the amide-bridged macrocyclic tetramer [Pd(L1)]4.     

Thermal and Spectral Characterization of 5-Cholro-2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)

The thermal stabilities of 5-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) were studied in air and nitrogen atmospheres. The complexes were obtained as mono-, di-, tetra-and pentahydrates with a metal to ligand ratio of 1:2 and with colours typical for M²⁺ ions (Mn-slightly pink, Co-pink, Ni-green, Cu-blue and Zn-white) and as polycrystalline compounds. When heated they dehydrate to form anhydrous salts which nextare decomposed to the oxides of the respective metals in air while in nitrogen to the mixtures of metal oxides and oxychlorides and carbon. The most thermally stable in air, nitrogen and argon atmospheres is 5-chloro-2-methoxybenzoate of Cu(II) while the least thermally stable is that of Co(II). This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis and characterisation of Ni(II), Cu(II), and Zn(II) complexes with an acyclic Mannich base functionalised with thioglycolate moiety

New complexes ML(CNS)·nH₂O [M = Ni, n = 0.5; M = Cu, n = 4.5; M = Zn, n = 0.5, HL: 6-mercapto-(1,4,8,11-tetraazaundecanyl)-6-carboxylic acid)] have been synthesised, chemical analysed, and characterised by different spectroscopic techniques (IR, UV–Vis–NIR, ¹H NMR, EPR, ESI–MS), and magnetic measurements. Based on the IR spectra a dinuclear structure with the 1,3-CSN coordination was proposed for Ni(II) and Cu(II) complexes. The dinuclear structure of Cu(II) complex is also consistent with both magnetic behaviour and EPR spectrum. According to TG, DTG and DTA curves the thermal transformations are complex processes, including dehydration, Mannich base oxidative degradation and thiocyanate decomposition. The final product of decomposition is the most stable metallic oxide, as XRD data indicates. The new complexes were also screened for their microbicidal and antibiofilm properties.     

A novel class of Cd(II), Hg(II) turn-on and Cu(II), Zn(II) turn-off Schiff base fluorescent probes

N,N'-((5,5'-(quinoxaline-2,3-diyl)bis(1H-pyrrole-5,2-diyl))bis(methanylylidene))bis(4-methoxyaniline) 4 and N,N'-((5,5'-(quinoxaline-2,3-diyl)-bis(1H-pyrrole-5,2-diyl))bis(methanylylidene))dianiline 5 have been prepared and structurally characterized. The X-ray crystal structures of compounds 4 and 4a have been determined. These compounds displayed good sensitivity toward transition metal ions with Cd(II), Zn(II) turn-on and Cu(II), Hg(II) turn-off in fluorescence. It is an elegant example of on/off behavior like a lamp. When Cd(II) or Zn(II) is added into compounds 4 or 5, the lamp will switch on, and then when Cu(II) or Hg(II) is added into the mixture, the lamp will switch off. The binding properties of 4 and 5 for cations were examined by fluorescence spectroscopy. The fluorescence data and crystal structure indicate that a 1:1 stoichiometry complex is formed between compound 4 (or 5) and metal ions, and the binding affinity is very high. The recognition mechanism between compound 4 (or 5) and metal ion was discussed based on the their chemical constructions and the CHEF/CHEQ effect when they interacted with each other.     

Synthesis and application of a novel magnetic nanosorbent for determination of trace Cd(II), Ni(II), Pb(II), and Zn(II) in environmental samples

In this work for the first time, Fe₃O₄@SiO₂ core–shell nanoparticles functionalized with isatin groups as a magnetic nanosorbent was applied for the simultaneous extraction of trace amounts of cadmium(II), nickel(II), lead(II), and zinc(II). The characterization of this nanosorbent was studied using Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction, vibrating sample magnetometer and thermogravimetric analysis. The effect of several factors such as pH, amount of sorbent, extraction time, type and volume of the eluent, sample volume, sorption capacity, and potentially interfering ions was investigated. In the selected conditions, it was observed that the limits of detection were 0.11 ng mL^?1 for Cd(II), 0.28 ng mL^?1 for Ni(II), 0.47 ng mL^?1 for Pb(II), and 0.21 ng mL^?1 for Zn(II), and the maximum sorption capacity of this suggested magnetic nanosorbent was 120, 112, 100, and 100 mg g^?1 for Cd(II), Ni(II), Pb(II), and Zn(II), respectively. Also, the precision of the method (RSD%) for ten replicate measurements was found 2.5, 2.5, 2.8, and 3.1%, for Cd(II), Ni(II), Pb(II), and Zn(II) ions, respectively. Finally, the suggested procedure was applied for determination of cadmium(II), nickel(II), lead(II), and zinc(II) at trace levels in different water and agricultural products with satisfactory results.     

A study of polyamine complex formation with H+, Cu(II), Zn(II), Pb(II), and Mg(II) in aqueous solution

Summary The composition and stability of the following biogenic amine complexes have been investigated: 1,4-diaminobutane(Put), 4-azaoctane-1,8-diamine(Spd), 4,9-diazadodecan-1, 12-diamine(Spm) as well as homologues such as 1,3-diaminopropane(Put3), 4-azaheptane-1, 7-diamine(Spd3,3) and 4,8-diazaundecan-1,11-diamine(Spm3,3,3) with H⁺, Cu(II), Zn(II), Pb(II) and Mg(II). A potentiometric method was used. The VIS technique enabled the determination of coordination mode in copper/amine systems. It was found that Mg(II) does not form coordination compounds with any of the studied polyamines in solution. An increase in the concentration of ligand and metal was found to result in a stronger tendency towards the formation of protonated compounds accompanied by a decrease in the concentration of hydroxocomplexes. At physiologicalpH (7.4) an increase in the concentration of protonated compounds by approximately 15% was observed within the ligand concentration range from 0.001 mol dm^–3 to 0.0001 mol dm^–3 at a Cu(II) concentration of 0.000177 mol dm^–3.

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Untersuchungen zur Komplexbildung von Polyaminen mit H⁺, Cu(II), Zn(II), Pb(II) und Mg(II) in wäßriger Lösung

Zusammenfassung Anhand einer Analyse von potentiometrischen Daten wurden Zusammensetzung und Beständigkeit folgender biogener Aminkomplexe untersucht: 1,4-Diaminobutan(Put), 4-Azaoktan-1,8-diamin(Spd), 4,9-Diazadodekan-1,12-diamin(Spm), sowie auch deren Homologen 1,3-Diaminopropan(Put3), 4-Azaheptan-1,7-diamin(Spd3,3) und 4,8-Diazaundekan-1,11-diamin(Spm3,3,3) mit H⁺, Cu(II), Zn(II), Pb(II) und Mg(II). Mit Hilfe der VIS-Technik wurde die Koordinationsweise in Kupfer/Amin-Systemen bestimmt. Es wurde festgestellt, daß Mg(II) keine Koordinationsverbindungen mit den untersuchten Polyaminen bildet. Eine höhere Konzentration von Ligand und Metall führte zu stärkerer Tendenz der Bildung protonierter Verbindungen, wobei die Konzentration von Hydroxokomplexen kleiner wurde. Bei physiologischempH (7.4) wurde im Bereich der Ligand-Konzentration von 0.001 mol dm^–3 bis 0.0001 mol dm^–3 bei einer Cu(II)-Konzentration von 0.000177 mol dm^–3 ein Anstieg der Konzentration protonierter Verbindungen um etwa 15% beobachtet.

     

Synthesis of a novel unsymmetrical Zn(II) phthalocyanine bearing a phenyl ethynyl moiety as sensitizer for dye-sensitized solar cells

A new unsymmetrical zinc phthalocyanine sensitizer has been synthesised. The anchoring of the molecule to nanocrystalline TiO(2) films is realised by a carboxylic group connected to a phenyl ethynyl moiety. Density Functional Theory (DFT) calculations show significant and positive effects of such a functionalization. Electron injection into the semiconductor and photocurrent generation in DSSC are also presented.     

Synthesis, characterization and antitumor activity of Cu(II), Co(II), Zn(II) and Mn(II) complex compounds with aminothiazole acetate derivative

This paper presents the synthesis of complex compounds of type [M(L1)₂], where M(II)= Cu (1), Co (2), Zn (3), L1=2-aminothiazole-4-acetate and [Mn(L1)₂(H₂O)] (4) using ethyl 2-(2-aminothiazole-4-yl) acetate (L), and characterization by elemental analysis, magnetic susceptibilities, IR, 1H-NMR, UV-Vis spectroscopy and for [Mn(L1)₂(H₂O)] also by X-ray diffraction. In vitro cytotoxicity studies were performed on human cervix adenocarcinoma, HeLa cells. The antitumor selectivity was assessed using normal human peripheral blood mononuclear cells, PBMC as control.      

Synthesis and spectroscopic studies of novel Cu(II), Co(II), Ni(II) and Zn(II) mixed ligand complexes with saccharin and nicotinamide

Four novel mixed ligand complexes of Cu(II), Co(II), Ni(II) and Zn(II) with saccharin and nicotinamide were synthesised and characterised on the basis of elemental analysis, FT-IR spectroscopic study, UV–Vis spectrometric and magnetic susceptibility data. The structure of the Cu (II) complex is completely different from those of the Co(II), Ni(II) and Zn(II) complexes. From the frequencies of the saccharinato CO and SO₂ modes, it has been proven that the saccharinato ligands in the structure of the Cu complex are coordinated to the metal ion ([Cu(NA)₂(Sac)₂(H₂O)], where NA — nicotinamide, Sac — saccharinato ligand or ion), whilst in the Co(II), Ni(II) and Zn(II) complexes are uncoordinated and exist as ions ([M(NA)₂(H₂O)₄](Sac)₂).     

Synthesis,Spectral and Structural Characterization of the First Bis-2-Pyridylethanol Complexes of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) Saccharinates: Crystal Structures of Diaquabis(2-Pyridylethanol)Iron(II) and Copper(II) Saccharinates

The first 2-pyridylethanol (pyet) complexes of manganese(II), iron(II), cobalt(II), nickel(II), copper(II) and zinc(II) saccharinates, were synthesized and characterized by elemental analyses, magnetic measurements, UV-Vis, and IR spectroscopic techniques. Crystal and molecular structures of the iron(II) and copper(II) complexes were determined by single crystal X-ray diffractometry. The experimental data showed that all the complexes are mononuclear with a general formula [M(H₂O)₂(pyet)₂](sac)₂, where sac is the saccharinate anion. All the metal ions are octahedrally coordinated by two aqua and two pyet ligands. The pyet ligand acts as a bidentate ligand through its amine nitrogen and hydroxyl oxygen atoms forming a six-membered chelate ring, while the sac ions remain outside the coordination sphere. All the complexes are isomorphous with a monoclinic space group P2₁/n and Z = 2.     

Synthesis,Structural Characterization,and Antimicrobial Activities of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) Complexes of Triazole‐based Azodyes

The synthesis and characterization of new transition metal complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with 3‐(2‐hydroxynaph‐1‐ylazo)‐1,2,4‐triazole ( HL¹ ) and 3‐(2‐hydroxy‐3‐carboxynaph‐1‐ylazo)‐1,2,4‐triazole ( HL² ) have been carried out. Their structures were confirmed by elemental analyses, thermal analyses, spectral and magnetic data. The IR and ¹H NMR spectra indicated that HL¹ and HL² coordinated to the metal ions as bidentate monobasic ligands via the hydroxyl O and azo N atoms. The UV‐Vis, ESR spectra and magnetic moment data revealed the formation of octahedral complexes [Mn L¹ (AcO)(H₂O)₃] ( 1 ), [Co L¹ (AcO)(H₂O)₃]·H₂O ( 2 ), [Mn L² (AcO)(H₂O)₃] ( 6 ) and [Co L² (AcO)(H₂O)₃] ( 7 ), [Ni L¹ (AcO)(H₂O)] ( 3 ), [Zn L¹ (AcO)(H₂O)]·H₂O ( 5 ), [Ni L² (AcO)(H₂O)] ( 8 ), [Zn L² (AcO)(H₂O)]·10H₂O ( 10 ) have tetrahedral geometry, whereas [Cu L¹ (AcO)(H₂O)₂] ( 4 ) and [Cu L² (AcO)(H₂O)₂]·5H₂O ( 9 ) have square pyramidal geometry.. The mass spectra of the complexes under EI‐con‐ ditions showed the highest peaks corresponding to their molecular weights, based on the atomic weights of ⁵⁵Mn, ⁵⁹Co, ⁵⁸Ni, ⁶³Cu and ⁶⁴Zn isotopes; besides, other peaks containing other isotopes distribution of the metal. Kinetic and thermodynamic parameters of the thermal decomposition stages were computed from the thermal data using Coats‐Redfern method. HL² and complexes 6 – 10 were found to have moderate antimicrobial activities against Staphylococcus aureus (gram positive), Escherichia coli (gram negative) and Salmonella sp bacteria, and antifungal activity against Fusarium oxysporum, Aspergillus niger and Candida albicans. Also, in most cases, metallation increased the activity compared with the free ligand.     

Syntheses and structures of isoindoline complexes of Zn(II) and Cu(II): an unexpected trinuclear Zn(II) complex

Deprotonation of the tridentate isoindoline ligand 1,3-bis[2-(4-methylpyridyl)imino]-isoindoline, 4'-MeLH, and reaction with hydrated zinc(II) perchlorate produces an unexpected trinuclear Zn(II) complex, [Zn(3)(4'-MeL)(4)](ClO(4))(2).5H(2)O (1), whereas reaction with hydrated copper(II) perchlorate in methanol produces the expected mononuclear product, [Cu(4'-MeL)(H(2)O)(2)]ClO(4) (2). X-ray diffraction shows that the trinuclear Zn(II) complex (1) contains a linear zinc backbone, and the arrangement of ligands about the outer chiral zinc(II) atoms is helical. The two terminal zinc ions exhibit approximate C(2) site symmetry, with tetrahedral coordination by two pyrrole and two pyridyl nitrogen atoms of the potentially tridentate isoindoline ligands. The central zinc ion exhibits approximate tetrahedral symmetry, with coordination by four pyridyl nitrogen atoms of four different isoindoline ligands. Pyridyl-pyrrole intramolecular pi-stacking interactions contribute to the stability of the trinuclear cation. The structure of the mononuclear copper(II) complex cation in 2 is best described as a distorted trigonal bipyramid. The isoindoline anion binds Cu(II) in both axial positions and one of the equatorial positions; water molecules occupy the other two equatorial positions.     

Highly selective photo-catalytic dimerization of alpha-methylstyrene by a novel palladium complex with photosensitizing ruthenium(II) polypyridyl moiety

A novel dinuclear complex containing the photo-sensitizing Ru unit and a Pd center is effective toward selective catalytic dimerization of alpha-methylstyrene leading to 2,4-diphenyl-4-methyl-1-pentene under visible-light irradiated conditions.