Reaction Of NiCl2 Research Articles

Tellurium azamacrocycles: synthesis, characterization and coordination studies

The metal-free condensation of bis(2-formylphenyl) telluride ( 1) with a series of diamines affords macrocyclic tellurium ligands 2– 7. Crystals of the protonated macrocycle 8 are monoclinic, space group P2/ n with a=10.890(5), b=7.414(4), c=24.334(13) Å, Z=2. The reaction of tellurium containing macrocyclic Schiff base 2 with Pd(C 6H 5CN) 2Cl 2 gives the expected 1:1 product [Pd(II) 2] Cl 2 ( 9). Complex 9 was treated with excess of NH 4PF 6 in methanol to give the analogous PF 6 − salt [Pd(II) 2] (PF 6) 2 ( 10). The crystals of 10 are monoclinic, space group P2 1/ n, a=8.2250(10), b=21.280 (4), c=21.150 (4), Z=4. However, the reaction of 2 with Pt(COD)Cl 2 proceeds via novel transmetallation to yield an organoplatinum complex ( 11). The crystals of 11 are also monoclinic, space group P2 1/ n, a=12.3253 (14), b=14.6557 (14), C=13.4054 (11), Z=4. The octahedral Ni(II) complex 12 was prepared by the reaction of NiCl 2 · 6H 2O with 2 and NH 4PF 6 under an inert atmosphere. For 12: triclinic, space group P 1 ̄ ; Z=2; a=10.800(8), b=13.468(9), c=13.918(11), α=89.67(6)°, β=101.53(7)°, γ=81.49(3)° and V=1961(3). Cyclic voltammetry of 12 in MeCN solution shows a well-behaved quasi-reversible (Δ E=100 mV) Ni(III) ↔ Ni(II) couple.

Synthesis of nanocrystalline Ni 2B via a solvo-thermal route

Nickel boride (Ni 2B) nanocrystals were successfully synthesized via the reaction of NiCl 2 and NaBH 4 at 420 °C with benzene as solvent. The yield is about 60%. The crystals were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectra (XPS). Highly crystallized Ni 2B with an average size of 20 nm was obtained.

Polymeric aqua(μ4-maleato-κ4O)pyridylnickel(II)

The title nickel coordination polymer, [Ni(C4H2O4)(C5H5N)(H2O)]n, has been obtained from the reaction of NiCl2·6H2O with disodium maleate and pyridine in an alcohol–water solution. Single-crystal X-ray analysis revealed that each Ni atom contains an approximately octahedral coordination environment in the compound with the maleate ligand in a novel coordination mode. The molecule has mirror symmetry. O—H⋯O hydrogen bonds exist in the corrugated two-dimensional structure; this is further extended into a three-dimensional framework via strong non-classical C—H⋯O interactions between adjacent layers.

Synthesis, X‐ray Powder Structure, and Magnetic Properties of Layered NiII Methylphosphonate, [Ni(CH3PO3)(H2O)], and NiII Octadecylphosphonate, [Ni{CH3‐(CH2)17‐PO3}(H2O)

[Ni(CH(3)PO(3))(H(2)O)] (1) and [Ni(CH(3)-(CH(2))(17)-PO(3))(H(2)O)] (2) were synthesised by reaction of NiCl(2).6 H(2)O and the relevant phosphonic acid in water in presence of urea. The compounds were characterised by elemental and thermogravimetric analyses, UV-visible and IR spectroscopy, and their magnetic properties were studied by using a SQUID magnetometer. The crystal structure of 1 was determined "ab initio" from X-ray powder diffraction data and refined by the Rietveld method. The crystals of 1 are orthorhombic, space group Pmn2(1), with a=5.587(1), b=8.698(1), c=4.731(1) A. The compound has a hybrid, layered structure made up of alternating inorganic and organic layers along the b direction of the unit-cell. The inorganic layers consist of Ni(II) ions octahedrally coordinated by five phosphonate oxygen atoms and one oxygen atom from the water molecule. These layers are separated by bilayers of methyl groups and van der Waals contacts are established between them. A preliminary structure characterisation of compound 2 suggests the crystallisation in the orthorhombic system with the following unit-cell parameters: a=5.478(7), b=42.31(4), c=4.725(3) A. The oxidation state of the Ni ion in both compounds is +2, and the electronic configuration is d(8) (S=1), as determined from static magnetic susceptibility measurements above 50 K. Compound 1 obeys the Curie-Weiss law at temperatures above 50 K; the Curie (C) and Weiss (theta) constants were found to be 1.15 cm(3) K mol(-1) and -32 K, respectively. The negative value of theta indicates an antiferromagnetic exchange coupling between near-neighbouring Ni(II) ions. No sign of 3D antiferromagnetic long-range order is observed down to T=5 K, the lowest measured temperature. Compound 2 is paramagnetic above T=50 K, and the values of C and theta were found to be 1.25 cm(3) K mol(-1) and -24 K, respectively. Below 50 K the magnetic behavior of 2 is different from that of 1. Zero-field cooled (zfc) and field-cooled (fc) magnetisation plots do not overlap below T=21 K. The irreversible magnetisation, DeltaM(fc-zfc), obtained as a difference from fc and zfc plots starts to increase at T=20 K, on lowering the temperature, and it becomes steady at T=5 K. The presence of spontaneous magnetisation below T=20 K indicates a transition to a weak-ferromagnetic state for compound 2.

Neutral β-diketiminato nickel(II) monoalkyl complexes

Reaction of NiCl 2(2,4-lutidine) 2 ( 1) with Tl[Me 2NN] ( 3) in THF results in the transmetallation of the β-diketiminate ligand from which the tetrahedral {[Me 2NN]NiCl} 2 ( 4) was isolated in poor yield. After filtration of the TlCl formed in the reaction between 1 and 3 in THF, addition of Grignard reagents RMgBr results in the isolation of monoalkyl complexes [Me 2NN]Ni(R)(2,4-lutidine) (R=Me ( 5), Et ( 6), Pr ( 7)) in 40–70% yield. X-ray structures 5– 7 of show these monoalkyls to be somewhat crowded, square planar species. NMR studies of the diamagnetic monoalkyl complexes show that lutidine dissociation/reassociation occurs on the NMR timescale at room temperature. In ethyl and propyl complexes 6 and 7, an equilibrium between the four coordinate [Me 2NN]Ni(R)(2,4-lutidine) and a lutidine-free species [Me 2NN]Ni(R) (R=Et, Pr) is observed. Broad, high-field 1H resonances consistent with the presence of β-H agostic alkyl groups are observed for the base-free species. The observation of two broad upfield 1H NMR signals at δ −2.7 and −7.3 ppm for the base-free Ni–propyl complex suggests a mixture of primary and secondary β-agostic isomers that reversibly interconvert by β-H elimination/reinsertion. Ethylene slowly inserts into monoalkyls 5– 7 demonstrate to give highly branched ethylene oligomers.

Structural and spectroscopic characterisation of bis-ligand complexes of iron(ii), nickel(ii) and nickel(iii) with the hydrotris(methimazolyl)borate anion: soft S6 donor sets generating a weak ligand field

Reaction of iron(II) and nickel(II) halides with sodium hydrotris(methimazolyl)borate (NaTm) results in the formation of 2 ∶ 1 complexes [M(Tm)2]. Crystallographic characterisation reveals in both cases trigonally distorted octahedral geometry in an S6 donor set. Spectroscopic properties indicate that the Tm ligand generates a weak ligand field, with Dq between that of H2O and Cl− and this is confirmed by the high-spin configuration of the iron(II) complex. Both complexes display classical paramagnetic behaviour. Mössbauer spectroscopy of the iron complex is also consistent with a high-spin complex. Reaction of NiCl2·6H2O with [Tl(Tm)] results in a small quantity of a material which is crystallographically demonstrated to be [Ni(Tm)2]Br.

Solid state complexes of nickel(II) and 4-imidazoleacetic acid: X-ray crystallography and spectroscopic investigation

The stoichiometric reaction of NiCl2·6H2O with sodium 4-imidazoleacetate Na(IA) in absolute MeOH yields blue crystals of Ni(IA)2·4H2O·2MeOH (1). This product decomposes rapidly in air, losing two MeOH molecules and producing Ni(IA)2·4H2O (2). Compound (1) when left in the mother liquor, slowly recrystallizes forming [Ni(IA)2(MeOH)2] (3), which is stable in air and suitable for single crystal X-ray diffraction studies. These crystals consist of slightly distorted octahedral coordination units in which the carboxylic oxygen, imidazole N3 nitrogen and the MeOH oxygen atoms act as coordination centers. The i.r. features, due to MeOH molecules, were employed to characterize the compounds studied. The reflectance spectrum of (3) was interpreted on the basis of octahedral and tetragonal symmetry of the NiO4N2 chromophore.

Bisphosphino ureas: flexible ligands with rigid backbone

The nickel(0) complex [Ni{ η 2-(PPh 2NMe) 2CO}{ η 1-(PPh 2NMe) 2CO}] 1 was obtained by the reaction of NiCl 2·6H 2O with two equivalents of the ligand (PPh 2NMe) 2CO in the presence of zinc as reducing agent. The structure of 1 was unambiguously determined by 1H and 31P–{ 1H} NMR spectroscopy and compared to the known structures of the extremely strained Pd(II) and Mo(0) complexes of (PPh 2NMe) 2CO.

Synthesis and characterisation of ring-coupled cyclopentadienyl and indenyl bimetallic derivatives of nickel

The reaction of NiCl 2(PPh 3) 2 with 0.5 equivalents of the salts Li 2[CMe 2(C 5H 4) 2] ( 1), Li 2[CMe 2(C 9H 6) 2] ( 2) or Li 2[(C 5H 4)CMe 2(C 9H 6)] ( 3) is an efficient route to the synthesis of ring-coupled cyclopentadienyl and indenyl homobimetallic nickel derivatives. The new binuclear complexes [Cl(PPh 3)Ni{μ-(η-C 5H 4)CMe 2(η-C 5H 4)}Ni(PPh 3)Cl] ( 4), [(PPh 3) 2Ni{μ-(η-C 5H 4)CMe 2(η-C 5H 4)}Ni(PPh 3) 2][PF 6] 2 ( 5), [(PPh 3) 2Ni{μ-(η-C 9H 6)CMe 2(η-C 9H 6)}Ni(PPh 3) 2][PF 6] 2 ( 6), [Cl(PPh 3)Ni{μ-(η-C 5H 4)CMe 2(η-C 9H 6)}Ni(PPh 3)Cl] ( 7), [(PPh 3) 2Ni{μ-(η-C 5H 4)CMe 2(η-C 9H 6)}Ni(PPh 3)Cl][PF 6] ( 8), [(PPh 3) 2Ni{μ-(η-C 5H 4)CMe 2(η-C 9H 6)}Ni(PPh 3) 2][PF 6] 2 ( 9) have been prepared and characterised. The X-ray crystal structure of 5 is reported.

Solvothermal Synthesis, Crystal Structure, and Properties of the New Oxothiomolybdate Ni( dien)2[Mo2O2S6

The reaction of NiCl2 · 6H2O, Na2MoO4 ċ 2H2O, and sulfur in a mixture of diethylenetriamine and 0.2 M ammonia solution (1:4) under solvothermal conditions leads to the formation of orange-red crystals of the oxothiomolybdate Ni(dien)2[Mo2O2S6] (dien = diethylenetriamine) in nearly 100% yield. The structure consists of [Ni(dien)2]2+ cations and discrete dimeric [Mo2O2S6]2− anions. The compound crystallizes in the monoclinic space group P21/c (a = 8.726(2), b = 18.111(4), c = 14.419(3) A, β = 101.686(3)°). Upon heating the compound decomposes in a single step starting at about 250°C. The final decomposition product was identified by X-ray powder diffractometry as MoS2 and Ni3S2. Spectroscopic data as well as detailed synthetic procedures for Ni(dien)2[Mo2O2S6] are reported.

Bis(3,5-dimethylpyrazole-1-carbodithioato) Nickel(II) and Its Transformation to a Dinuclear Complex: Crystal Structure of [Ni2(μ-3,5-Me2Pz)2(L1)2] (L1 = 3,5-dimethylpyrazole-1-carbodithioate)

The reaction of NiCl2·6H2O with potentially bidentate N,S donor pyrazole-1-carbodithioate ligands produces four-coordinated diamagnetic NiIIN2S2 complexes quantitatively. In solution Ni(L1)2 (L1 = 3,5-dimethylpyrazole-1-carbodithioate) transforms to dimeric bis(3,5-dimethylpyrazole-1-carbodithioato) bis(μ-3,5-dimethylpyrazolato)dinickel(II), [Ni2(μ-3,5-Me2Pz)2(L1)2] (1).

Interaction of Ni(II) with 2,3-dihydroxybenzoic acid

The reaction of NiCl 2·6H 2O with 2,3-dihydroxybenzoic acid=L in n-PrOH:H 2O=1:1 solution, produced the complex {[Ni 5L 5(OH) 7]K 4·13H 2O} n . Its structure was investigated using elemental analysis, IR, UV–Vis, NMR and ES MS spectroscopy. The complex is unstable in aqueous solution and its decomposition scheme was proposed on the basis of NMR and ES MS spectra. This may contribute to the understanding of oxidative degradation of catecholic derivatives by Ni(II), as well as to other similar ones.

Chemical Syntheses of Nanocrystalline Nickel Aluminides

Nanocrystalline nickel aluminides (nano-NiAl and nano-Ni3Al) are synthesized by reactions of NiCl2 and LiAlH4 in Et2O or 1,3,5-trimethylbenzene, followed by annealing of the reaction products at 55...

Solvothermal synthesis to NiE 2 (E = Se, Te) nanorods at low temperature

NiE 2 (E = Se, Te) nanorods were directly synthesized through the reaction of NiCl 2 and selenium or tellurium in an autoclave at 160 ∼ 180°C for 10 ∼ 15 h, using ethylenediamine as a solvent. X-ray powder diffraction patterns and transmission electron microscope images show that the products are cubic NiSe 2 and hexagonal NiTe 2 phase, respectively, in the form of well-crystallized nanorods. A possible mechanism of the formation of NiE 2 nanorods in the solvothermal process is proposed. The solvent ethylenediamine plays an important role in the formation of NiE 2 nanorods.

Non-linear optical absorption of [{Ni(mnt) 2} 2] 2− and its unique counter ion, a disodium triple-decker dication [Na 2(benzo-15-crown-5) 3(H 2O) 2] 2+

Reaction of NiCl 2·6H 2O and Na 2[mnt] (mnt=maleonitriledithiolate) in CH 3OH at room temperature leads to Ni(II) dithiolato complex [Ni(mnt) 2] 2−. An oxidation process of [Ni(mnt) 2] 2− affords [{Ni(mnt) 2} 2] 2− and yields solid crystalline product [Na 2(benzo-15-crown-5) 3(H 2O) 2][{Ni(mnt) 2} 2] ( 1) in the presence of benzo-15-crown-5. X-ray diffraction analyses revealed that in solid state the dianions of 1 pack as columns and the counter ions are discrete disodium triple-decker dications. A non-linear absorption coefficient β of 2.4 cm GW −1 was recorded at 1064 nm for 1 in acetonitrile solution with a concentration of 1.0×10 −4 mol l −1.

Oxoanion influences on the self-assembly of cationic co-ordination complex polymers of the nickel(II)–di-4-pyridylamine family

Hydrothermal reactions of NiII, di-4-pyridylamine (dpa) and the appropriate oxide yield materials of the NiII–organodiamine–EO42– family. Specifically, reaction of NiCl2·6H2O, dpa, and MoO3 in water at 120 °C yielded [Ni(dpa)2(MoO4)] 1, while the reaction of NiSO4·6H2O and dpa in water at 120 °C gave [Ni(dpa)(SO4)(H2O)]·2H2O 2. The structures reveal the dramatic influence of the anion identity and ligation modes in the {Ni(dpa)n}n2n+ substructure. The structure of 1 is constructed from two motifs, two-dimensional {Ni(dpa)}n2n+ sheets and one-dimensional {NiMoO4}n chains, to produce a three-dimensional covalently linked framework. In contrast, the {Ni(dpa)}n2n+ substructure of 2 is three-dimensional, with co-ordinated SO42– and aqua ligands projecting into channels formed by the {Ni(dpa)}n2n+ framework. The void is reduced through the common characteristic of interpenetration, such that the structure of 2 exhibits two independent three-dimensional frameworks.

Microstructural evolution of Ni-NaCl mixtures during mechanochemical reaction and mechanical milling

The evolution of microstructure of Ni and NaCl mixtures formed by mechanochemical reaction and mechanical milling has been studied using X-ray diffraction, electron microscopy and magnetic measurements. Separate nano-sized Ni particles were formed by continuous solid-state reaction of NiCl2 + 2Na during mechanical milling. Further milling resulted in the growth of clustered particles due to inter-particle welding during collision events. On the other hand, milling of micron-sized Ni and NaCl powders resulted in a layered particle morphology and continuous decrease in particle size with increasing milling time.

One-dimensional co-ordination polymers formed by crown ether metal cation bridges: synthesis and crystal structure of nickel(II) dithiolene complexes [{Na(benzo-15-crown-5)}2 Ni(i-mnt)2]n · nCH2Cl2 and [{Na(benzo-15-crown-5)}2Ni(mnt)2

Reaction of NiCl2 · 6H2O, Na2[i-mnt] and benzo-15-crown-5 in CH3OH⧹CH2Cl2 at room temperature leads to [{Na(benzo-15-crown-5)}2Ni(i-mnt)2]n · nCH2Cl2 (1). The same reaction with Na2[mnt] instead of Na2[i-mnt] affords [{Na(benzo-15-crown-5)}2Ni(mnt)2]n (2). Both complexes were isolated as crystalline products. X-ray diffraction analyses reveal that the main segments of 1 and 2 are infinite train structures, in which the building blocks Ni(i-mnt)2 or Ni(mnt)2 in end-to-end arrangements act as body frames and crown cycles standing by the body frames play the role of cartwheel. They are joined with each other through sodium ions.

Synthesis, structures, and magnetic properties of binuclear carboxylate complexes with NiII and NiIII atoms

The reaction of NiCl2·6H2O with Me3CCOOH and KOH taken in a molar ratio of 1:2:2 in water afforded the nonanuclear antiferromagnetic complex Py2Ni2(Me3CCOOH)2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2), which apparently contains NiII and NiIII atoms. The complex was isolated by extraction with CH2Cl2, benzene, or hexane. The reactions of this complex with pyridine bases (pyridine (Py), 3,4-lutidine (Lut), and nicorandil (Nic)) gave the adducts L4Ni2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH) (L=Py, Lut, or Nic, respectively). According to magnetic measurements, intramolecular ferromagnetic exchange interactions in these adducts are complemented by intermolecular antiferromagnetic interactions. Pyrolysis of the pyridine adduct in air or under an inert atmosphere in xylene yielded the antiferromagnetic complex Py2Ni2(Me3CCOOH)2(OOCCMe3)2(μ-OOCCMe3)2(μ-OH2), which contains NiII atoms. The structures of all the complexes synthesized were established by X-ray diffraction analysis. The electronic absorption spectra of these compounds are considered.

Zero-valent group 10 metal complexes with a triphosphine ligand, [M(dpmp) 2], where MPt, Pd, Ni, and dpmp = bis(diphenylphosphinomethyl)phenylphosphine

Reduction of [MCl 2(dpmp)] by NaBH 4 in the presence of dpmp afforded zero-valent mononuclear complexes, [M(dpmp) 2], in good yields (41–86%), where MPt ( 4), Pd ( 5), Ni ( 6), and dpmp = bis(diphenylphosphinomethyl)phenylphosphine. The nickell ( II) starting complex, [NiCl 2(dpmp)] ( 3), was prepared by the reaction of NiCl 2·6H 2O with dpmp and was characterized by X-ray crystallography to be isomorphous with [PdCl 2(dpmp)] ( 2) ( 3·CH 2Cl 2: monoclinic, P2 1/c, a = 10.886(4), b = 21.867(5), c = 13.786(4) A ̊ , V = 3265 A ̊ 3, Z = 4, R = 0.071 and R w = 0.062) . Th 31P( 1H) NMR spectra of 4–6 were similar to each other showing three multiplets. The structure of 4 was shown by X-ray analysis to have a mononuclear Pt atom tetrahedrally coordinated by two dpmp ligands through four terminal phosphorus atoms ( 4·4 C 6 H 6: monoclinic, P2/c, a = 13.563(8), b = 17.098(7), c = 16.995(7) A ̊ , V = 3774 A. Z = 2, R = 0.007 and R w = 0.059 ). The central P atom of dpmp was uncoordinated. Reaction of 4 with [Pt(XyINC) 4](PF 6) 2 (XyINC = 2.6-xylyl isocyanide) gave a mixture of isomteric diplatinum complexes, syn- and anti-[Pt 2(dpmp) 2(XyINC) 2](PF 6) 2 ( syn-7 and anti-7).