Characterization Of Nickel Research Articles

Preparation and solid-state characterization of nickel(II) complexes with 1′-(diphenylphosphino)ferrocenecarboxylic acid

1′-(Diphenylphosphino)ferrocenecarboxylic acid (Hdpf) reacts with nickel(II) halides and nickel(II) thiocyanate to give the paramagnetic complexes [NiX2(Hdpf-κP)2] (X = Cl, 1; Br, 2; I, 3) and the diamagnetic planar isothiocyanato complex [Ni(SCN-κN)2(Hdpf-κP)2] (4), respectively. In situ neutralization of Hdpf followed by reaction with nickel(II) sulfate affords the salt [Ni(dpf)2] (5). The halide complexes 1–3 easily undergo dissociative decomposition in polar donor solvents; compound 5 is insoluble in all common solvents. All compounds were characterized by IR and UV/vis spectroscopies and magnetic measurements in the solid state. The solid-state structure of the solvate 4·2CHCl3 was determined by single-crystal X-ray diffraction. A series of complexes, including the ligand Hdpf and its Ca salt (6) as reference compounds, were further studied by X-ray photoelectron spectroscopy. Spectral data and magnetic measurements indicate compound 5 contains the dpf − anion as a P,O-coordinated ligand.

Synthesis and characterization of nickel(II) bis(alkylthio)salen complexes.

NiX2(2-RSC6H4CH=NCH2CH2N=CHC6H4SR-2) (NiX2L; L = 5) (1a, X = Br, R = C6H13; 1b, X = Cl, R = C12H25) and NiX2(2-C6H13SC6H4CH2NHCH2CH2NHCH2C6H4SC6H13-2) (NiX2L; L = 6) (2a, X = Br; 2b, X = Cl; 2c, X = OClO3) were prepared from ligands 5 and 6, respectively. The 1:2 metal-ligand complex Ni(OClO3)2(2-RSC6H4CH2NHCH2CH2NHCH2C6H4SR-2)2 3, was obtained from an EtOH solution of 2c. The characterization of paramagnetic 1-3 included single-crystal X-ray diffraction studies of 1a and 3. Complex 2c converted into 3 in the presence of excess ligand 6 in CHCl3.

Synthesis and Characterization of Nickel–Poly(St-co-AA)Composite Nanospheres by Ultraviolet Irradiation

Nickel nanoparticles on poly(St-co-AA) spheres have been synthesised by seeded emulsion polymerization followed by ultraviolet reduction.

Synthesis and characterization of nickel(II) complexes of a tetraaza macrocycle containing axial ligands

The octahedral complexes [NiLX 2] (X=OH 2 ( 1), ONO − ( 2) and NCO − ( 3); L=3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0 1.18,0 7.12]docosane) have been prepared and characterized by X-ray crystallography. The crystal structures of the [NiLX 2] complexes have an axially elongated octahedral geometry with two axial ligands and adopt the trans-III configuration. Magnetic moments, electronic spectra and redox potentials of the [NiLX 2] complexes also reveal a high-spin octahedral geometry, which is reflected by the nature of the axial ligands.

Synthesis and Characterization of Nickel(II) Compixxes of Zacetylpyridine Thiosemicarbm, One

Nickel(II) complexw of 2-acetylpyridine thiosemicarbazone (HL) were synthesized and charactecrized by clemnntal analys, magnetic moment measurements, conductivity measurements, electronic and IR spectral studies. Implications of the magnetic and spectral data in retlation to the structures of the complexes are discussed.

Synthesis and Characterization of Nickel–Poly(St-co-AA) Composite Nanospheres by Ultraviolet Irradiation

Nickel nanoparticles on poly(St-co-AA) spheres have been synthesised by seeded emulsion polymerization followed by ultraviolet reduction.

Preparation and Characterization of Nickel–poly(St-co-AA) Composite Nanoparticles

Poly(St-co-AA) particles were prepared by seeded emulsion polymerization. The nickel ions absorbed on poly(St-co-AA) particles were reduced by hydrated electrons produced by ultraviolet irradiation. The metal nickel–copolymer composite particles were obtained by ultraviolet irradiation for the first time. These metal nickel–copolymer composite particles were further characterized by XRD and TEM measurements.

Synthesis, spectroscopic studies and solid state electrical conductivity of Ni(II) polymeric complexes. The crystal structure of the complex [Ni(L1)Cl2] · EtOH were L1=1,2-bis(2′-pyridylbenzyleneimino)benzene

The preparation and the characterization of nickel(II) complexes with the neutral, N 4 non-macrocyclic Schiff base ligands L1=1,2-bis(2′-pyridylbenzyleneimino)benzene and L2=1,2-bis(2′-pyridylethyleneimino)benzene, of formulae Ni(LX)Cl 2 are reported. The structure of the complex, [Ni(L1)Cl 2] · EtOH, has been determined by X-ray diffraction methods. The nickel atom has a six coordinate NiN 4Cl 2chromophore with distorted octahedral coordination, while the ligand L acts as a tetradentatechelate, with the ligated atoms in an essentially planar arrangement around the metal and the remaining axial coordination sites occupied by chloro ligands. The reactions of the above complexes and that of Ni(L3)Cl 2 with 1,4-phenyldiisocyanide (phdi) formed polymeric compounds of the type [(LX)Ni(phdi)] n Cl 2 n which have been characterized by elemental analysis, magnetic susceptibility measurements, IR and UV-Visspectroscopic techniques. The solid state electrical conductivity of the polymeric complexes was approximately 10 −7 (Ω · m) −1, which further increased by partial oxidation with I 2.

Synthesis and Characterization of Nickel(II) and Palladium(II) Pyrrolyl Complexes and Their Polymerization to Electroactive Materials

Four new transition metal−pyrrolyl complexes, bis(pyridyl)bis(pyrrolyl)palladium(II), (2,2‘-bipyridyl)bis(pyrrolyl)palladium(II), (6-phenyl-2,2‘-bipyridine)(pyrrolyl)palladium(II), and bis(trimethylphosphino)(pyrrolyl)nickel(II) chloride, have been prepared and characterized. DFT calculations indicate that radical cations of the palladium compounds and their dimers have spin densities primarily on the pyrrolyl ligand, while the spin density of the nickel species radical is diffuse. Each complex was found to undergo oxidative polymerization to semiconducting polymers with good thermal properties. Polymers prepared with dodecylbenzenesulfonate as the counterion were soluble and could be cast into smooth, films with good physical properties.

Synthesis and characterization of nickel(II) complexes of di- N-alkylated 14-membered tetraaza macrocycles containing cyclohexane rings via regioselective alkylation reaction

Square-planar nickel(II) complexes of new di- N-alkylated 14-membered tetraaza macrocycles 6,17-dimethyl (L 5),6,17-diethyl (L 6), and 6,17-bis(n-propyl) (L 7) derivatives of 3,14-dimethy1-2,6,13,17-tetraazatricyclo-[16,4,0 1.18O, 7.12]docosane (L 1) have been prepared by one-step, regioselective reaction of [NiL 1] 2+ with RI (R  Me, Et, or n-Pc) in basic Me 2SO solution. The nickel(II) complexes were characterized by 1H and 13C NMR spectroscopy and/or by single crystal X-ray crystallography. Crystal structures of [NiL 1] (ClO 4) 2 and the di- N-propyl derivative [NiL 7] (ClO 4) 2 show that the two complexes have normal square-planar coordination geometries with the nickel atoms lying on the N 4 planes; however, the NiN bond distances of the latter are about 0.03 Å longer than those of the former. The electronic spectra, redox potentials and/or structures of the nickel(II) complexes are strongly affected by the presence of N- and C-substituents, but little affected by the nature of the N-alkyl groups.

Synthesis, magnetic and spectral studies of nickel(II) and zinc(II) complexes of 4-formylantipyrine N(4)-substituted thiosemicarbazones

The synthesis and characterization of nickel(II) and zinc-(II) complexes with 4-formylantipyrine N(4)-methyl-, N(4)-dimethyl- and 3-piperidylthiosemicarbazones are reported. Elemental analyses, molar conductivities, magnetic measurements and spectral (i.r., electronic and n.m.r.) studies have been used to characterize the complexes. The i.r. spectra show that the thiosemicarbazones behave as bidentate or tridentate ligands, either in the thione or thiolato form. Stereochemistries are proposed for the complexes on the basis of spectral and magnetic studies.

Synthesis and Characterization of Nickel and Manganese Vanadium Oxides

ABSTRACTWe have synthesized novel nickel and manganese vanadium oxides using the hydrothermal reactions of vanadium(V) pentoxide, Ni(CH3COO)2, and MnSO4 with an organic templating cation at 165°C. The [NH2(CH2)2NH2]2NiV6O14 has a monoclinic structure. It has some disordered V and 0 atoms in the V6014 layer, which appear to be very close to each other with occupation factor around 0.5. The disordered model was decomposed for two ordered configurations, which differ in the stacking of the layers. The (Mn+2)6(Mn+3)l−2/3z(OH)3(1−Z)(VO4)3[(VO4)l−2z(v207)z] (Z≈0. 1) phase has a hexagonal pipe morphology. These compounds were also characterized by electron microprobe, FTIR and TGA. They reacted readily with lithium, and their electrochemical behavior in lithium cells was determined.

Electrochemical Testing and Structural Characterisation of Nickel Based Catalytic Coatings Produced by Direct Spraying

AbstractIn this paper a novel processing technique has been used to produce a range of low overpotential nickel based electrocatalytic coatings for use in the Chlor-alkali industry. These coatings include pure nickel as well as Raney nickel alloys, with particular focus upon the beneficial effects of molybdenum additions to Raney nickel.Structural characterisation of all coatings has been carried out using X-ray diffraction for quantitative phase identification, backed up by optical and electron microscopy for analysis of phase distribution. Measurement of the coatings' electrochemical properties has been performed in fully functioning micro-pilot scale electrolysis cells.

Synthesis and characterization of nickel(II) complexes with symmetrical tetradentate N2O2 naphthaldimine ligands. Their application as catalysts for the hydrogenation of cyclohexene

Ni acetate reacts with naphthaldimines containing the N2O2 donor group to yield two types of complex. The first, of molecular formula NiL (L=naphthaldimine), is free of the anions in which the ligand behaves as a dibasic tetradentate towards one Ni ion. These complexes are all diamagnetic, having square planar geometry. In the second type, the ligand behaves either as a monobasic acid towards the Ni ion or as a neutral molecule. These complexes are paramagnetic and exhibit a tetrahedral configuration around the central metal ion. The metal chelates were characterized by elemental analyses (t.g.a. and d.t.a.), and by i.r. and u.v.–vis. spectroscopy. Magnetic moments were also measured. A series of NiII–Schiff base complexes were tested for their catalytic activity in the hydrogenation of cyclohexene with molecular H2. The effects of the bridge length, amounts of solvent and cosolvent were studied. The use of H2O as a cosolvent greatly increases the yield of the reaction product. The hydrogenation product yield is linearly related to the dielectric constant of the medium.

Preparation and Characterization of Nickel(II), Palladium(II), and Platinum(II) Complexes Containing (2-Aminoethyl)dimethylphosphine or the Related Didentate Phosphine Ligands

Abstract Here are described several new nickel(II), palladium(II), and platinum(II) complexes of bis(chelate)-type with didentate phosphine ligands having an amino or thioether donor group: Me2PCH2CH2NH2 (edmp), Ph2PCH2CH2NH2 (edpp), Me2PCH2CH2NMe2 (dmedmp), or Me2PCH2CH2SMe (mtdmp). Bis(tetrafluoroborate) salts of [M(P–N or S)2]2+ (M = Ni, Pd, and Pt; (P–N or S) = the ligands above) have been prepared and the geometrical structures determined by NMR spectroscopy. All the palladium(II) complexes prepared in this study are cis-isomers, in contrast to the analogous Me2PCH2CH2S− (dmsp) complex (trans-[Pd(dmsp)2]), which indicates that the anionic phosphine-thiolate ligand prefers the trans geometry more than the neutral phosphine-amine or -thioether ligand does. The dichloride salts of the bis(edmp) complexes, cis-[M(edmp)2]Cl2 (M = Ni (4a), Pd(5a), and Pt(6a)), and those of the bis(edpp) complexes have been obtained as crystals, while the corresponding salts of dmedmp, mtdmp, and 8-(dimethylphosphino)quinoline complexes can not be isolated due to their oily properties. Further, addition of LiBF4 to a methanolic solution of 4a, 5a, or 6a gives exclusively a precipitate of the chloride tetrafluoroborate salt, cis-[M(edmp)2]Cl(BF4) (M = Ni (4c), Pd(5c), or Pt(6c)). The crystal structures of 4a, 5c, and 6a determined by X-ray analyses indicate a weak (not strong enough to form a five-coordinated complex) interaction between cis-[M(edmp)2]2+ and Cl− anion. The average M–N bond lengths in 4a, 5c, and 6a are considerably longer than those in the corresponding 1,2-ethanediamine complexes, owing to the strong trans influence of the –PMe2 group in edmp. The order of strength of the trans influence among NiII, PdII, and PtII triad metal series is non-periodical: NiII < PtII < PdII. This order is similar to the order among CoIII, RhIII, and IrIII triad metal series found in our previous study on fac-[M′(edmp)3]3+ (M′ = CoIII, RhIII, and IrIII) complexes.

Synthesis, crystal structure and characterization of nickel(O) acrylonitrile complexes with a bidentate N-donor ligand

Three nickel(O) acrylonitrile complexes with a bidentate N-donor ligand, [Ni(biL)(AN) 2] (biL=4,4′-dimethyl-2,2′-bipyridine (Me 2bpy); 1, 2,2′-dipyridylamine (dpa); 2, 2,2′-pyridylbenzimidazole (pbi); 3, AN=acrylonitrile), have been prepared and characterized. The crystal structures have been determined by X-ray single-crystal diffraction. Complex 1 is triclinic, space group P 1 , with a = 10.279(2), b = 11.071(1), c = 7.5409(9) Å, α= 95.68(1), β = 99.26(1), γ=85.03(1)°, U= 840.6(2) Å 3, Z= 2, R=0.032 and R w=0.038. The nickel atom of 1 is coordinated by two N atoms of Me 2bpy and the CC moiety of two AN molecules, providing a distorted tetrahedral geometry. Complexes 2 and 3 have the following crystal data: 2, monoclinic space group P2 1/ n, a=8.755(4), b=13.713(2), c=12.740(2) Å, β=92.94(2)°, U=1527.5(8) Å 3, Z=4, R=0.038 and R w=0.039; 3, monoclinic space group P2 1/ n, a = 12.829(3), b = 8.068(1), c = 17.024(2) Å, β=107.62(1)°, U=1679.5(5) Å 3, Z = 4, R = 0.033 and R w=0.036. The geometries of 2 and 3 are similar to that of 1 except for the dihedral angles. The average NiN distance is 2.004, 2.034 and 2.045 Å for 1, 2 and 3, respectively. The average CC distance of AN is 1.402(2), 1.403(6) and 1.409(4) Å for 1, 2 and 3, respectively. These CC distances are rather longer than that of free AN (1.343 Å), indicating contribution from a large π back-donation. The IR and 1H NMR results also support the presence of π back-donation.

Nickel(II) and manganese(II) complexes of substituted phenanthroline ligands

The synthesis and characterization of nickel(II) and manganese(II) complexes of substituted 1, 10-phenanthroline ligands are described.; The ligands include 2, 9-di( o-tolyl)-1, 10-phen (dtphen), 2, 9-di(2-methoxyphenyl)-1, 10-phen (dmophen), 2, 9-di(2-ethoxyphenyl)-1,10-phen (deophen), 2-( o-tolyl)-1, 10-phen (tphen), 2-(2-ethoxyphenyl)-1, 10-phen (eophen) and 2, 9-bis( N-pyrazolylmethyl)1, 10-phen (bpmp). 1:1 Metal-to-ligand complexes have been isolated with dmophen and bpmp, and 1:2 metal-to-ligand complexes have been isolated with all ligands except bpmp. The structure of 1:1 nickel(II) complex with dmophen has been determined by three-dimensional X-ray diffraction methods. The complex [Ni(dmophen)Cl 2], [NiC 26H 20N 2O 2Cl 2], crystallizes in the space group Pccn of the orthorhombic system with eight molecules in a cell of dimensions a=14.572(3), b=16.741(3) and c=19.209(4) Å. The structure has been refined to a final value of the crystallographic R factor of 0.0427 based on 2618 observed independent reflections. There are two crystallographically independent, but geometrically very similar, molecules in the cell, each lying on a twofold axis. The complex is roughly tetrahedral, the coordination being provided by two ligand phen nitrogen atoms and by two chloride ions. Electrochemical data for the 1:2 complexes suggest that the M(II)↔M(I) electron transfer process is essentially metal localized, but that the M(I)↔M(0) electron transfer process is ligand localized. Moreover, the electrochemical results demonstrate that the 2, 9-di( o-substituted phenyl)-1,10-phen ligands are able to stabilize lower oxidation states, and that ligand binding to the reduced metal ion prevents its dissociation into free ligand and metal.

Inversion of configuration around the seven-coordinated cobalt center induced by an interaction between sugars and tetrahedral oxoanions

Carbohydrates have a widespread Occurrence in nature and are indispensable compounds to living organisms.' Naturally rare carbohydrates have also proved to be involved in many glycoproteins, glycolipids, and antibiotics and play important roles in various biological processesS2 Further, in some enzymatic reactions of carbohydrates, alkali, alkaline earth, and some of transition metal ions were suggested to act in cooperation with sugars.3 In this regard, it is very important to investigate the interactions between sugars and metal ions including the stereochemical behavior of sugars in transition metal complexes. We have studied the synthesis and characterization of nickel(I1) and cobalt(II1) complexes containing N-glycosides derived from the reaction of sugars and diamine^.^ Here, we wish to report a synthesis of novel seven-coordinated cage-type cobalt complexes containing N-glycosides from mannose-type aldoses (D-mannose or L-rhamnose (=6-deoxy-~-mannose)) and tris(Zaminoethy1)amine (tren) and an unprecedented inversion of configuration around the metal center induced by an interaction between sugars and tetrahedral oxoanions. A methanolic solution containing D-mannose (D-Man) or L-rhamnose (L-Rha) (4 equiv) and tren (1 equiv) was incubated at 60 OC for 1 h. Then, CoXz.6HzO (X = C1-, B r ) (1 equiv) was added to the solution and the mixture was refluxed for 1 h. The resultant solution was purified on a Sephadex LH-20 gel permeation column. The wine-red major band was collected and concentrated, and an addition of ethanol gave microcrystals of [Co((aldose)3-tren)]Xz.nHzO (la, aldose = D-Man, X = C1-; lb, aldose = L-Rha, X = C1-; 2a, aldose = D-Man, X = B r ; 2b, aldose = L-Rha, X = B r ) , where (aldose)3-tren is tris(N-aldosyl2-aminoeth~l)amine.~ When CoSOcnHzO was used as a metal source, similar complexes formulated as [C~((aldose)~-tren)]S04.nH20 (3a, aldose = D-Man; 3b, aldose = L-Rha) were ~ b t a i n e d . ~ The electronic absorption (AB) spectra of 1-3 in solution showed a characteristic band around 20 X lo3 cm-I, corresponding to d-d transitions of Co(I1) ions. The transmittance spectra (Nujol mull) also showed a similar absorption indicating no significant structural change around the metal on dissolution. In the circular dichroism (CD) spectra, a large Cotton effect was observed at about 20 X 103 cm-l, suggesting the coordination of sugar moieties to the cobalt ion. Further, it should be noted that the sign of the Cotton effect of 1 and 2 containing halide

Synthesis and characterization of nickel and magnesium ferrites obtained from α-NaFeO 2

Synthesis and characterization of nickel and magnesium ferrites obtained by ionic exchange reactions in molten salts are presented. Although their structure is quite close to the spinel one, the ideal composition MFe 2O 4 (M:Ni, Mg) is not obtained. Instead, some extra octahedral sites are occupied thus, the structure is better described as intermediate between the spinel and defective NaCl one.

Multifunctional macrocyclic ligands. Synthesis and characterization of nickel(II) and cobalt(II) macrocyclic-catechol complexes and their dimeric, antiferromagnetically coupled, semiquinone derivatives

Multifunctional macrocyclic ligands. Synthesis and characterization of nickel(II) and cobalt(II) macrocyclic-catechol complexes and their dimeric, antiferromagnetically coupled, semiquinone derivatives