Luminescence Determination of Copper(I), Silver(I), Gold(I), and Platinum(II) Using 2-Mercapto-5-Benzimidazolesulfonic Acid,also Immobilized on a Silica Surface

2-Mercapto-5-benzimidazolesulfonic acid (MBI), also noncovalently bound to a silica surface, is proposed as a reagent for the low-temperature luminescence determination of Cu(I), Ag(I), Au(I), and Pt(II). Luminescence excitation and luminescence spectra of metal complexes with MBI in solutions and on the adsorbent surface represent broad unstructured bands in the regions 250–400 and 450–700 nm, respectively. The developed procedures for the luminescence and sorption–luminescence determination of Cu, Ag, Au, and Pt with limits of detection at a level of 0.001–0.01 μg on 0.1 g of adsorbent are tested in the determination of metals in natural and industrial samples.     

Synthesis and Study of Co(II), Ni(II), and Cu(II) Ethylenediaminetetraacetatohydroxogermanates

New heterometallic Ge(IV) and Co(II), Ni(II), and Cu(II) complexonates based on ethylenediaminetetraacetic acid (H₄Edta) were synthesized. The composition of the complexes was determined using elemental analysis and thermogravimetry. Comparison of the IR spectra of [Ge(OH)(HEdta)] ? H₂O, which was structurally characterized previously, with those of the new complexes provided information on the composition and structure of their inner and outer spheres. The cobalt and nickel coordination polyhedra were identified by analyzing the diffuse reflection spectra and the effective magnetic moments and that of copper was identified by EPR.     

The infrared spectra (3500—150 cm-1) of aniline complexes of cobalt(II), nickel(II), copper(II) and zinc(II) halides

The IR spectra (3500—150 cm^?1) of the complexes [M(aniline)₂,X₂ (M = Co, Ni, Cu, Zn; X = Cl, Br), [Zn(aniline)₂I₂] are discussed. Assignments of the internal ligand vibrations are based on the band shifts which result from ¹⁵N-labelling of the amino group. The metal—ligand stretching frequencies, ν(M—N) and ν(M—X), are assigned on the basis of the band shifts which occur on ¹⁵N-labelling and metal ion and halogen substitution. Two bands within the range 350–450 cm^?1 are assigned to ν(M—N) while the ν(M—X) bands occur within the range 170–320 cm^?1. The effects of structure and coordination number on ν(M—N) and ν(M—X) are discussed. The spectra of two ethanol adducts, [M(aniline)₂-(ethanol)₂Cl₂] (M = Co, Ni) compared with those of the unsolvated species [M(aniline)₂-Cl₂], exhibit a unique band near 480 cm^?1 which is insensitive to ¹⁵N-labelling and is assigned to ν(M—O).     

Chelating activity of bis(diacetylmonoxime)thiocarbohydrazone towards VO2+, Co(II), Ni(II), Cu(II) and Pt(IV) ions

A new chelating agent, bis(diacetylmonoxime)thiocarbohydrazone (H₃DMT), has been synthesized from reaction between diacetylmonoxime and thiocarbohydrazide. The prepared ligand, characterized by elemental analysis, IR and ¹H?NMR spectra, is a strong chelating agent and indicator. Its coordinating properties have been studied toward VO²⁺, Co(II), Ni(II), Cu(II) and Pt(IV) ions. The data revealed the formation of mononuclear complexes with Co(II) and Pt(IV) and binuclear complexes with the rest. In all complexes, the ligand binds in its deprotonated form through the oxime and hydrazone nitrogens as well as the thiol or thione sulfur forming five- and six-membered rings. All complexes exhibit an octahedral structure except for the Cu(II) which has a square-pyramidal geometry based on the spectral and magnetic studies. The ESR spectra of the Cu(II) and VO²⁺ complexes are in good agreement with the structural results. The color change from acidic (yellow) to basic (reddish brown) media gives the ligand the ability to become as an analytical indicator for weak acid–weak base titrations.     

Synthesis and characterization of N,N-diethylnicotinamide-acetylsalicylato complexes of Co(II), Ni(II), Cu(II), and Zn(II)

N,N-diethylnicotinamide-acetylsalicylato complexes of Co(II), Ni(II), Cu(II), and Zn(II) were synthesized and investigated by elemental analysis, magnetic susceptibility, solid state UV–Vis, direct injection probe mass spectra, FTIR spectra and thermoanalytic TG-DTG methods. The complexes contain two waters, two acetylsalicylate (asa) and two N,N-diethylnicotinamide (dena) ligands per formula unit. The acetylsalicylate and N,N-diethylnicotinamide are monodentate through acidic oxygen and nitrogen of pyridine ring. Decomposition of each complex starts with dehydration then decomposition of N,N-diethylnicotinamide and acetylsalicylate, respectively. The thermal dehydration of the complexes takes place in one or two steps. The decomposition mechanism and thermal stability of the investigated complexes are interpreted in terms of their structures. The final decomposition products are found to be metal oxides.     

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.     

Separation and structural studies of manganese(II), cobalt(II), nickel(II), copper(II) and cadmium(II) complexes of benzilic and mandelic esters

Summary Solid metal complexes of benzilic and mandelic esters have been prepared and their structure elucidated using vis., i.r., n.m.r. and e.s.r. spectra. The results of elemental analysis are commensurate with the proposed formulae. Spectral studies indicate that the Ni complexes are octahedral, whereas the Co and Cu analogoues are distorted octahedral.     

Salisaldehyde-2-aminobenzimidazole schiff base complexes of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)

New metal complexes of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with salicylidine-2-aminobenzimidazole (SABI) are synthesized and their physicochemical properties are investigated using elemental and thermal analyses, IR, conductometric, solid reflectance and magnetic susceptibility measurements. The base reacts with these metal ions to give 1:1 (Metal:SABI) complexes; in cases of Fe(III), Co(II), Cu(II), Zn(II) and Cd(II) ions; and 1:2 (Metal:SABI) complexes; in case of Ni(II) ion. The conductance data reveal that Fe(III) complex is 2:1 electrolyte, Co(II) is 1:2 electrolyte, Cu(II), Zn(II) and Cd(II) complexes are 1:1 electrolytes while Ni(II) is non-electrolyte. IR spectra showed that the ligand is coordinated to the metal ions in a terdentate mannar with O, N, N donor sites of the phenloic -OH, azomethine -N and benzimidazole -N3. Magnetic and solid reflectance spectra are used to infer the coordinating capacity of the ligand and the geometrical structure of these complexes. The thermal decomposition of the complexes is studied and indicates that not only the coordinated and/or crystallization water is lost but also that the decomposition of the ligand from the complexes is necessary to interpret the successive mass loss. Different thermodynamic activation parameters are also reported, using Coats-Redfern method. This revised version was published online in July 2006 with corrections to the Cover Date.     

Spectroscopic Studies on Co(Ⅱ),Ni(Ⅱ),Zn(Ⅱ) Complexes with 4,4'-Bipyridine

Fourier-transform infrared(FTIR),Raman and ultraviolet-visible spectra of 4,4'-bipyridine and its me-tal-organic coordination compounds synthesized from 4,4'-bipyridine and nitrate of Co(Ⅱ),Ni(Ⅱ) and Zn(Ⅱ) were measured and analyzed,respectively.The main FTIR and Raman bands were assigned in detail.The relationship between these characteristic bands and the structure of ligands and coordination compounds were discussed.     

四溴四苯基卟啉及其金属配合物的电子结构和四溴四苯基卟啉Ni(II)的晶体结构

本文合成了7, 8, 17, 18-四溴-5, 10, 15, 20-四苯基-21, 23(H)-卟啉(H~2TPPBr~4)及其金属配合物MTPPBr~4[M=Cu(II), Ni(II), Co(II)和Zn(II)]。测定了它们的可见紫外光谱和循环伏安, 用四轨道模型(Four Orbital Model)计算了MTPPBr~4的相对前线轨道, 并解释了配合物的可见紫外光谱及电化学性质。测定了NiTPPBr~4的晶体结构, 晶体属单斜晶系, 空间群C2/c, a=2.6077(7),b=1.0414(4), c=1.9312(3)nm, β=137.1(7)°, Z=4, 最后偏离因子R=0.067, 晶体结构直接证明了卟啉亲电溴化反应具有区域选择性, 四个溴分布在相对两个吡咯环上。     

Infrared spectra of o-toluidine and m-toluidine complexes of Co(II), Ni(II), Cu(II) and Zn(II) halides

The infrared spectra of eighteen metal complexes of empirical formula [ML₂X₂] (M = Co, Ni, Cu or Zn; L = o^? or m-toluidine; X = Cl, Br or I) have been determined over the range 4000-150 cm^?1. Assignments of the internal vibrations of the amino group are based on the band shifts induced by ¹⁵N-labelling of the nitrogen donors. Bands within the range 400–600 cm^?1 are assigned to the metal-nitrogen stretching frequency (vM-N) on the grounds of their sensitivity to ¹⁵N-labelling and metal ion substitution and their absence of sensitivity to halide substitution. Bands within the range 350–150 cm^?1 are assigned to the metal-halogen stretching frequency (vM-X) on the basis of their sensitivity to halide and metal ion substitution and their insensitivity to ¹⁵N-labelling. Structural aspects of the spectra are discussed and the present assignments are compared with those previously reported.     

Mass spectral behavior of some homoleptic and mixed aryldichalcogenide bis(diphenylphosphino)ferrocenenickel(II), palladium(II), and platinum(II), and bis(diisopropylphosphino)ferrocenepalladium(II) complexes

The mass spectral behavior of a number of organometallic complexes containing the Group 10 metals Ni, Pd, and Pt, together with various thiolate ligands were studied. For Pd, two main types of complexes, differing by the substituents on the phosphorus atom were studied. Types I and II were substituted with bis(diphenylphosphino)ferrocene and bis(diisopropylphosphino)ferrocene ligands, respectively. The Ni complexes, except for one, and the Pd Type I complexes had no molecular radical cations (M(+.)) in their EI spectra. On the other hand, all the Pt complexes showed intense M(+.) ions in their EI spectra indicating that these complexes were more stable as radical cations than those of Ni and Pd. The FAB and MALDI spectra of all the complexes displayed intense quasi-molecular ions (MH(+)) and the fragmentations in both modes were similar. The MALDI spectra of several complexes displayed only M(+.) ions while one gave evidence of both MH(+) and M(+.) ions. Several Pd Type II complexes yielded intense M(+.) in their EI spectra.     

Synthesis of pyridin-3-yl-functionalized silica as a chelating sorbent for solid-phase adsorption of Hg(II), Pb(II), Zn(II), and Cd(II) from water

Silica gel modified with 3-aminopropyltrimethoxysilane was anchored with nicotinaldehyde to prepare a new chelating surface (or matrix). It was synthesized and characterized by elemental analysis, cross-polarization magic-angle spinning ¹³C nuclear magnetic resonance (NMR) spectroscopy, diffuse reflectance infrared Fourier-transform spectroscopy, nitrogen adsorption–desorption isotherm, Brunauer–Emmett–Teller surface area, and Barrett–Joyner–Halenda pore sizes. The new surface exhibits good chemical and thermal stability as determined by thermogravimetry curves. This new organic–inorganic material was used for preconcentration of Hg(II), Pb(II), Zn(II), and Cd(II) from water prior to their determination by inductively coupled plasma atomic emission spectrometry. The optimum pH for quantitative sorption of these metal ions is in the range of 6–8, and the sorption capacity is in range of 486–1,449 μmol/g. By batch method, 95 % extraction takes ≤30 min. All the metals could be desorbed with a solution of hydrochloric acid (6 N) without loss of the expensive ligand. Solutions of the metal ions were prepared by dissolution of the nitrate solution.     

Synthesis,spectral, thermal,and magnetic studies of cobalt(II), nickel(II), copper(II), zinc(II), and cadmium(II) complexes with N2O2 donor groups

A new Schiff base ligand was prepared by condensation of 2-hydroxy-4-methoxybenzaldehyde with 1,2-propanediamine. The ligand and its metal complexes were characterized by elemental analysis, FT-IR, ¹H and ¹³C NMR, magnetic moment, molar conductance, UV-Vis, SEM and thermal analysis (TGA). The molar conductance measurements indicated that all the metal complexes were non-electrolytes. IR spectra showed that ligand (L) behaves as a neutral tetradentate ligand and binds to the metal ions by the two azomethine nitrogen atoms and two phenolic oxygen atoms. The electronic absorption spectra and magnetic susceptibility measurements indicated square planar geometry for the Ni(II) and Cu(II) complexes while other metal complexes showed tetrahedral geometry. Also the surface morphology of the complexes was studied by SEM.     

Synthesis,structural studies and bio-activity of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with p -amino acetophenone salicyloyl hydrazone

Complexes of the type [M(pash)Cl] and [M(Hpash)(H₂O)SO₄] (M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); Hpash = p-amino acetophenone salicyloyl hydrazone) have been synthesized and characterized by elemental analyses, molar electrical conductance, magnetic moments, electronic, ESR and IR spectra, thermal studies and X-ray powder diffraction. All the complexes are insoluble in common organic solvents and are non-electrolytes. The magnetic moment values and electronic spectra indicate a square-planar geometry for Co(II), Ni(II) and Cu(II) chloride complexes and spin-free octahedral geometry for the sulfato complexes. The ligand coordinates through >C=N–,–NH₂ and a deprotonated enolate group in all the chloro complexes, and through >C=N–, >C=O and–NH₂ in the sulfato complexes. Thermal analyses (TGA and DTA) of [Cu(pash)Cl] show a multi-step exothermic decomposition pattern. ESR spectral parameters of Cu(II) complexes in solid state at room temperature suggest the presence of the unpaired electron in d _{x ² ? y ²} . X-ray powder diffraction parameters for [Cu(pash)Cl] and [Ni(Hpash)(H₂O)SO₄] correspond to tetragonal and orthorhombic crystal lattices, respectively. The complexes show a fair degree of antifungal activity against Aspergillus sp., Stemphylium sp. and Trichoderma sp. and moderate antibacterial activity against E. coli and Clostridium sp.     

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.     

Zinc(II), Cobalt(II) and Nickel(II) Complexes of 5-Substituted-1,3,4-Thiadiazoles

Zn(II), Co(II) and Ni(II) complexes with some 5-substituted-1,3,4-thiadiazoles (L₁-L₄) have been prepared and characterized by conductivity, microanalysis, thermal analysis, infrared and electronic spectra measurements. All complexes behave as 1:1 electrolyte and the ligands are coordinated as bidentate molecules. The stability constants and energy of formation are determined and discussed on the basis of the ligands structure.     

Synthesis and characterization of iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of salicylidene-N-anilinoacetohydrazone (H2L1) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H2L2)

Salicylidene-N-anilinoacetohydrazone (H(2)L(1)) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H(2)L(2)) and their iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes have been synthesized and characterized by IR, electronic spectra, molar conductivities, magnetic susceptibilities and ESR. Mononuclear complexes are formed with molar ratios of 1:1, 1:2 and 1:3 (M:L). The IR studies reveal various modes of chelation. The electronic absorption spectra and magnetic susceptibility measurements show that the iron(III), nickel(II) and cobalt(II) complexes of H(2)L(1) have octahedral geometry. While the cobalt(II) complexes of H(2)L(2) were separated as tetrahedral structure. The copper(II) complexes have square planar stereochemistry. The ESR parameters of the copper(II) complexes at room temperature were calculated. The g values for copper(II) complexes proved that the Cu-O and Cu-N bonds are of high covalency.     

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.     

Application of Multivariate Calibration Methods for the Simultaneous Multiwavelength Spectrophotometric Determination of Fe(II), Cu(II), Zn(II), and Mn(II) in Mixtures

Abstract

A sensitive method for the simultaneous spectrophotometric determination of Fe(II), Cu(II), Zn(II), and Mn(II) in mixtures has been developed with the aid of multivariate calibration methods, such as classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS). The method is based on the spectral differences of the analytes in their complexation reaction with 4‐(2‐pyridylazo)‐resorcinol (PAR) and the use of full spectra with wavelengths in the range of 300–600 nm. It was found that both the spectral positive and negative bands obtained against the PAR blank, are proportional to the concentration for each metal complex. The obtained linear calibration concentration ranges are 0.025–0.6, 0.05–0.8, 0.025–0.8, and 0.05–0.8 µg ml^?1 for Fe(II), Cu(II), Zn(II), and Mn(II), respectively, and the LODs for the four metal ions were found to be approximately 1–3×10^?2 µg ml^?1. The proposed method was applied to a verification set of synthetic mixtures of these four metal ions, with models built in three different wavelength ranges, i.e., 300–450, 450–600, and 300–600 nm, corresponding to the positive, negative bands and their combinations, respectively. It was shown that the PLS model for the 300–600 nm range gave the best results (RPE_T=6.9% and average recovery ～100%; cf. PCR: RPE_T=9.5% and average Recovery ～110%). This method was also successfully applied for the determination of the four metal ions in pharmaceutical preparations, chicken feedstuff, and water samples.