Thermal decomposition of complexes of Co(II), Ni(II) and Zn(II) ions with thiosalicylic acid or ethylenediamine

The thermal decompositions of crystalline Co(II), Ni(II) and Zn(II) complexes with thiosalicylic acid or ethylenediamine were investigated via the respective thermal curves. On the basis of the decomposition temperatures, the following sequences of stabilities of the studied compounds have been proposed: 1. [Co(SR)][Ni(SR)]<[Zn(SR)]; 2. [Zn(en)₂](NO₃)₂·2H₂O<[Co(en)₂](NO₃)₂<[Ni(en)₃](NO₃)₂.     

Nitrates and bis(dithiooxalato)nickelates(II) of biacetyldihydrazone complexes

Summary Biacetyldihydrazone (BdH) complexes [M(BdH)₃](NO₃)₂ (M=Co^II, Ni^II, Cu^II or Zn^II); [Fe(BdH)₃](NO₃)₃; [M(BdH)₃][Ni(dto)₂] (M=Co^II, Ni^II or Zn^II; dto=dithiooxalate); [Cu(BdH)₂][Ni(dto)₂] and [Fe(BdH)₃]₂[Ni(dto)₂]₃ have been prepared and characterized by chemical analysis, conductance measurements, electronic and i.r. spectral studies and cyclic voltammetry.A mononuclear octahedral configuration is proposed for all cationic complexes, excepting [Cu(BdH)₂][Ni(dto)₂, which is probably a dithiooxalate bridged dimer.     

Activity and Osmotic Coefficients from the Emf of Liquid Membrane Cells. X. Tris(Ethylenediamine) Cobalt(III) Nitrate, Perchlorate, and Chloride

Activity coefficients of [Co(en)₃](NO₃)₃ and [Co(en)₃](ClO₄)₃, to be compared with [Co(en)₃]Cl₃ and the corresponding lanthanum salts previously studied, are determined. [Co(en)₃]Cl₃ data are revised. Ion interaction strengths vary in the same order found for La³⁺, i.e., as if nitrate and perchlorate ions were of smaller and larger size, respectively, than chloride ions; however, the differences are much smaller than in lanthanum salts. Tris(ethylenediamine)cobalt III and lanthanum nitrate, chloride, and perchlorate—like the corresponding hexacyanoferrate(III) and hexacyanocobaltate(III) salts, but contrary to sulfate salts—behave as if [Co(en)₃]³⁺ were smaller in size than La³⁺. In the dilute regions, [Co(en)₃](NO₃)₃ displays negative deviations from the limiting slope, a kind of behavior typical for 2:2, 2:3, 3:2, and 3:3 electrolytes, but unnoticed earlier for 3:1 or 1:3 electrolytes. Pitzer's equation parameters able to provide accurate activity and osmotic coefficients for [Co(en)₃](NO₃)₃, [Co(en)₃](ClO₄)₃, and, revised, [Co(en)₃]Cl₃ are reported.     

Magnetic properties of biacetyldihydrazone complexes

Summary Magnetic susceptibilities of the biacetyldihydrazone (BdH) complexes [M(BdH)₃](NO₃)₂ (M = Co^II, Ni^II, Cu^II or Zn^II), [Fe(BdH)₃](NO₃)₃, [M(BdH)₃](Ni(dto)₂] (M = Co^II, Ni^II or Zn^II; dto = dithiooxalate), [(BdH)₂Cu(dto)Ni(dto)] and [Fe(BdH)₃]₂[Ni(dto)₂]₃ have been studied in the 4.2–295 K range. Zn^II complexes are diamagnetic, and complexes of Ni^II, Cu^II and Fe^III obey the Curie-Weiss law. The Co^II complexes behave anomalously and the results are interpreted in terms of a high spinlow spin equilibrium.     

[M(en)3] (ndt)•H2O的水热合成、晶体结构和光学性能 ( M=NiⅡ, CoⅡ, MnⅡ and ndt=1,5-naphthalenedithiolate )

水热条件下，合成了三个新的配合物[Ni(en)₃] (ndt) ·H₂O 1, [Co(en)₃] (ndt) ·H₂O 2 和[Mn(en)₃] (ndt) ·H₂O 3。晶体结构通过X-射线单晶衍射进行了表征。三个配合物均属于单斜晶系，Cc空间群。[M(en)₃]²⁺阳离子、ndt阴离子和结晶水分子通过氢键自组装出相同结构的三维网。通过紫外-可见-近红外漫反射光谱对这三个配合物的光吸收性能和能带进行了测定。     

Simultaneous light emission—differential thermal analysis of selected coordination compounds

A new apparatus which permits the simultaneous determination of both the light emission (LE) and differential thermal analysis (DTA) curves of a compound is described. LE—DTA curves are reported for a selected number of coordination compounds, each containing vigorous reducing—oxidizing ligands or ions. New LE curve peaks are reported for [Co(NH₃)₆](NO₃)₃, [Ni(en)₃](NO₃)₂, and [Rh(NH₃₅X](NO₃₂) (X = Cl, Br on NO₃) complexes. Multiple LE peaks were found for [Co dien (NO₃)₃], cis-[Co(en)₂(NO₂)₂] NO₂ and [Co dien NH₃(NO₂)₂]Cl. The presence of carbon-containing reducing ligand is not necessary in order to obtain a LE peak during the thermal dissociation process     

Single crystal circular and linear dichroism spectra and absolute configuration of M(en)3(NO3)2 (M = Zn(II), Cu(II), Ni(II), Co(II), Mn(II) and Ru(II)

The isomorphous single crystals of M(ethylenediamine)₃(NO₃)₂, where M is Zn(II), Ni(II) and Co(II), exhibit macroscopic optical activity as predicted by their acentric space group. Axial circular dichroism measurements on these pure crystals show conclusively that spontaneous resolution has occurred. The axial circular dichroism and orthoaxial linear dichroism spectra of these pure crystals, and of Cu(II), Ni(II), Co(II), Mn(II) and Ru(II) doped into the Zn(en)₃(NO₃)₂ crystal have been measured at ambient and cryogenic temperatures in the range from 7 to 35 kK. The first NO₃^? transition at 32.5 kK is assigned as ¹A ← ¹A based on its linear polarization and sign of rotational strength. The d-d transitions are assigned in the context of D₃ symmetry and reveal a small negative crystal field parameter k, consistent with theoretical prediction. A positive R for all d-d transitions is found to be associated with the Λ configuration for all of the complex ions, by correlation with the crystal and solution circular dichroism of Ru(en)₃²⁺.     

The infrared spectra of imidazole complexes of first transition series metal(ii) nitrates and perchlorates

The IR spectra (4000–4140 cm^?1 ) of the twelve imidazole (Him) complexes [M(Him)₆] (NO₃)₂ (M = Co, Ni, Zn); [M(Him)₆](ClO₄)₂ (M = Mn, Fe, Co, Ni); [Zn(Him)_s](ClO₄)₂; [Cu(Him)₄X₂] (X = NO₃, ClO₄); [Zn(Him)₄(NO₃)₂]; [Zn(Him)₄](ClO₄)₂ and their deuterated analogues are discussed. The ratio between the frequencies of corresponding bands in the deuterated and undeuterated species is used to assign the internal imidazole vibrations. The internal modes of the NO₃^? and ClO₄^? ions are discussed in relation to the known or proposed structures of the complexes. The metal-ligand vibrations are assigned on the grounds of the shifts which occur on imidazole deuteration and metal ion substitution.     

Synthesis and characterization of biacetyldihydrazone complexes of cobalt(II), copper(II), nickel(II) and iron(III)

Summary Biacetyldihydrazone (BdH) complexes [M(BdH)₃](ClO₄)₂ (M=Co^IIor Cu^II) and [M(BdH)₃](NO₃)_2,3 (M = Ni^IIor Fe^III) have been prepared and characterized by chemical analysis, conductance measurements, electronic, i.r. and e.p.r. spectral studies and magnetic subsceptibilities measurements. A mononuclear octahedral configuration is proposed for all complexes studied.     

A theoretical insight into the role of counter anions and their interactions in nitropentaamminecobalt(III) toward linkage isomerism-induced photochemical motion

Density functional theory (B3LYP, B3LYP-D3, wB97XD, M062X, and M06L) and ab initio methods (MP2 and CCSD(T)) in conjunction with 6-31+G(d,p) and LanL2DZ were employed to investigate the interaction energies between [Co(NH₃)₅NO₂]²⁺ linkage isomers and chloride and nitrate in both gas phase and solid state. The nature of the chemical bonding has been analyzed by means of the atoms in molecules, electron density shift, natural bond orbitals, symmetry adapted perturbation theory, and energy decomposition analysis. The electronic structures of the two lowest laying singlet states (S_o and S₁) of [Co(NH₃)₅NO₂](NO₃)Cl isomers were also investigated using CASSCF(6,6) with LanL2DZ and 6-31G(d) basis sets. Our results show that [Co(NH₃)₅NO₂]²⁺ linkage isomers interact more strongly with chloride than nitrate. The structures of [Co(NH₃)₅NO₂](NO₃)Cl linkage isomers and their relative stabilities were examined in gas phase and in solid state and confirmed the nitro-complex as the most stable following by a viable intermediate endo-complex. Study of the nitro-nitrito linkage isomerization in [Co(NH₃)₅NO₂](NO₃)Cl revealed that anions form strong electrostatic bonds with [Co(NH₃)₅NO₂]²⁺ leading to decrease in an activation energy compared to the [Co(NH₃)₅ONO]²⁺ isomers. A concerted action of ionic interactions and hydrogen bonds are suspected of regulating the isomerization in solid state. Assessment of various DFT methods with respect to CCSD(T) suggests M062X suitable method for [Co(NH₃)₅NO₂](NO₃)Cl linkage-isomerization study. Potential energy surface calculations at the CASSCF/6-31G(d) level of theory shows that the conical intersection (S₁/S_o) might play an important role in the photoisomerization of [Co(NH₃)₅NO₂](NO₃)Cl.     

Nickel(II) and cobalt(II) coordination compounds of dichloroguanidinopyrimidines

Summary New coordination compounds of Ni^II and Co^II with dichloropyrimidinoguanidine (L) have been obtained and characterized by physico-chemical and spectroscopic methods. The complexes have the general formulae: [ML₃](ClO₄)₂, [ML₂(SO₄)], [ML₂(NCS)₂], (M = Ni or Co), [NiL₂(ClO₄)₂] and [CoL₂](ClO₄)₂. The ligands are bonded to the metal ion via one nitrogen atom from the pyrimidine heterocyclic ring and one from the guanidine group.     

Dinuclear tetrapyridyl pendant-armed azamacrocyclic complexes of Co(II), Ni(II), Cu(II) and Cd(II)

The coordination capability of the new tetrapyridyl pendant-armed azamacrocyclic ligand L, towards Co(II), Ni(II), Cu(II) and Cd(II) ions was studied. The ligand and the complexes were characterized by microanalysis, LSI mass spectrometry, IR, UV-Vis and NMR spectroscopy, magnetic studies and conductivity measurements. Crystal structures of [Co₂L(CH₃CN)₂](ClO₄)₄·2CH₃CN and [Cd₂L(NO₃)₂](NO₃)₂·2H₂O complexes have been determined. The X-ray studies show the presence of dinuclear endomacrocyclic complexes with the metal ion in a similar distorted octahedral environment, coordinated by one pyridyl bridgehead group, two amine nitrogen atoms and two pyridyl pendant-arms. The sixth coordination position around the metal ion is completed by one acetonitrile molecule in [Co₂L(CH₃CN)₂](ClO₄)₄·2CH₃CN and by one monodentate nitrate anion in [Cd₂L(NO₃)₂](NO₃)₂·2H₂O. Different sort of intramolecular non-classical hydrogen bonds were found in the crystal lattice of both structures.     

Complexes of Co(II), Ni(II), and Cu(II) with 4-(3,4-dichlorophenyl)-1,2,4-triazole

Novel oligonuclear complexes of Co(II), Ni(II), and Cu(II) with 4-(3,4-dichlorophenyl)-1,2,4-triazole (L) of the composition [M₃L₁₀(H₂O)₂](NO₃)₆ (M = Co(II), Ni(II)), [Ni₃L₆(H₂O)₆]Hal₆ (Hal = Cl^?, Br^?), and [Cu₅L₁₆(H₂O)₂](NO₃)₁₀ · 2H₂O were synthesized and studied by magnetic susceptibility, electronic and IR spectroscopy, and powder X-ray diffraction methods. All the above complexes are X-ray amorphous. Antifer-romagnetic exchange interactions between the M²⁺ ions were discovered in the [Co₃L₁₀(H₂O)₂](NO₃)₆ and [Ni₃L₁₀(H₂O)₂](NO₃)₆ complexes, whereas ferromagnetic exchange interactions were observed in the complexes [Ni₃L₆(H₂O)₆]Cl₆, [Ni₃L₆(H₂O)₆]Br₆, and [Cu₅L₁₆(H₂O)₂](NO₃)₁₀ · 2H₂O.     

Bis{2,6‐bis[3‐(2,4,6‐trimethylphenyl)pyrazol‐1‐yl‐κN2]pyridine‐κN}cobalt(II) dinitrate at 290 and 150 K

The title compound, [Co(C₂₉H₂₉N₅)₂](NO₃)₂, contains a six‐coordinate high‐spin Co^II ion with approximate local D_2d symmetry. The bond lengths and angles at cobalt undergo only small changes between the two temperatures, which confirms that the Co^II ion does not undergo a spin‐state transition over this temperature range.     

Synthesis and Physicochemical Study of Iron(II), Cobalt(II), Nickel(II), and Copper(II) Complexes with 4-(2-Pyridyl)-1,2,4-Triazole

New complexes of iron(II), cobalt(II), and nickel(II) with 4-(2-pyridyl)-1,2,4-triazole (PyTrz), [Fe₃(PyTrz)₈(H₂O)₄]A₆ (A = NO₃ ^-, ClO₄ ^-, Br^-) and [M₃(PyTrz)₈(H₂O)₄](NO₃)₆ (M = Co, Ni), were synthesized and studied by X-ray diffraction, magnetochemical method, and electronic and IR spectroscopy. The complex [Fe₃(PyTrz)₈(H₂O)₄](NO₃)₆) was also studied by adiabatic calorimetry. The Fe(II), Co(II), and Ni(II) nitrate complexes were shown to be isostructural to the previously synthesized linear trinuclear [Cu₃(PyTrz)₈H₂O)₄](NO₃)₆ complex. In all compounds, antiferromagnetic exchange interactions between M²⁺ ions were detected. The complex [Fe₃(PyTrz)₈(H₂O)₄](NO₃)₆ undergoes the ¹ A ₁ ⁵ T ₂ spin transition.     

Hexa­aqua­nickel(II) bis­(hypophosphite)

The structure of hexa­aqua­nickel(II) bis­(hypophosphite), [Ni(H₂O)₆](H₂PO₂)₂, has been determined. The crystals are prismatic. The packing of the Ni and P atoms (not the entire hypophosphite anions) is the same as in the structures of [Co(H₂O)₆](H₂PO₂)₂ and [Co_0.5Ni_0.5(H₂O)₆](H₂PO₂)₂. The Ni^II cations have a pseudo‐face‐centered cubic cell, with cell parameter a 10.216 Å and tetrahedral cavities occupied by P atoms. The Ni^II cation has crystallographically imposed twofold symmetry and has an octahedral coordination sphere consisting of six water O atoms, two of which also lie on the twofold axis. The planes of oppositely coordinated water mol­ecules are in a cross conformation. The geometry of the hypophosphite anion is close to point symmetry mm2. The hypophosphite anions are hydrogen bonded to the coordinated water molecules.     

Thermal decomposition of polycrystalline [Ni(NH3)6](NO3)2

The thermal decompositions of polycrystalline samples of [Ni(NH₃)₆](NO₃)₂ were studied by thermogravimetric analysis with simultaneous gaseous products of the decomposition identified by a quadruple mass spectrometer. Two measurements were made for samples placed in alumina crucibles, heated from 303 K up to 773 K in the flow (80 cm³ min^?1) of Ar 6.0 and He 5.0, at a constant heating rate of 10 K min^?1. Thermal decomposition process undergoes two main stages. First, the deamination of [Ni(NH₃)₆](NO₃)₂ to [Ni(NH₃)₂](NO₃)₂ occurs in four steps, and 4NH₃ molecules per formula unit are liberated. Then, decomposition of survivor [Ni(NH₃)₂](NO₃)₂ undergoes directly to the final decomposition products: NiO_1+x, N₂, O₂, nitrogen oxides and H₂O, without the formation of a stable Ni(NO₃)₂, because of the autocatalytic effect of the formed NiO_1+x. Obtained results were compared both with those published by us earlier, by Farhadi and Roostaei-Zaniyani later and also with the results published by Rejitha et al. quite recently. In contradiction to these last ones, in the first and second cases agreement between the results was obtained.     

Metal-assisted transformation of N-benzoyldithiocarbazate to 5-phenyl-1,3,4-oxadiazole-2-thiol in the presence of ethylenediamine,and its first row transition metal complexes

The reaction of metal complexes of the type [M(HL)Cl] or [M(HL)₂] [where M = Cu(II), Ni(II), Mn(II), Co(II) and Zn(II) and H₂L = N-benzoyldithiocarbazate] with an excess of ethylenediamine (en) in CHCl₃–MeOH medium leads to ring closure by desulfurisation to yield unique mixed-ligand complexes 1–4, [Cu(en)₂](pot)₂(pot = 5-phenyl-1,3,4-oxadiazole-2-thiol), [M(en)₂(pot)₂] [M = Ni(II), Mn(II)] and [Zn(en)(pot)₂]. The metal complexes have been characterized by various physicochemical methods. The molecular structure of [Cu(en)₂](pot)₂ has been determined by a single crystal X-ray diffraction study. In the centrosymmetric unit of [Cu(en)₂](pot)_2, the metal ion has a square planar arrangement of four symmetry related N-atoms of two en groups and is ionically bonded to two pot anions. Weak interaction studies on the complex reveal the presence of a hydrogen-bonded network in the molecule involving non-coordinating donor atoms of the pot anion with en resulting in the formation of an extended three-dimensional network. The arrangement of the [Cu(en)₂]²⁺ units, at a dihedral angle of 49.43° to pot⁻, provides a network of intermingled chains leading to a π–π stacked 3-dimensional framework.     

硝酸碳酰肼合钴、镍、铜含能配合物结构和性质的理论研究

对硝酸三碳酰肼合钴([Co(CHZ)₃](NO₃)₂)、硝酸三碳酰肼合镍([Ni(CHZ)₃](NO₃)₂)和硝酸二碳酰肼合铜([Cu(CHZ)₂(NO₃)₂])进行密度泛函理论计算研究, 获得其稳定分子的几何构型、电子结构、红外光谱以及热化学性质. 研究结果表明, 这三种配合物均表现出六配位八面体结构, 而铜配合物中的硝酸根参与了配位. 自然键轨道分析表明, 配体和金属离子之间存在供体-受体相互作用, 致使配位氨基N—H键上的成键轨道电子发生离域, 进而导致氨基N—H键的电子占据数降低、键长增大、键级减小、伸缩振动频率红移, 这与实测红外光谱变化规律很好地吻合. 标题化合物的金属离子均为＋1氧化态, 金属-氮配位键都是共价键, 而Cu—O配位键是离子键. 通过计算求得理论反应热, 预测这些配合物的合成均为放热反应; 由生成热大小推测标题物的稳定性次序为[Ni(CHZ)₃](NO₃)₂＞[Co(CHZ)₃](NO₃)₂＞[Cu(CHZ)₂(NO₃)₂], 与实测热稳定性次序完全吻合.     

Steric effects on the electronic and molecular structures of nickel(II) and cobalt(II) 2,6-dipyrazol-1-ylpyridine complexes

The complexes [M(L¹R)₂](BF₄)₂ (M=Ni, Co; L¹R=2,6-dipyrazol-1-ylpyridine [L¹H], 2,6-bis-{3-iso-propylpyrazol-1-yl}pyridine [L¹Prⁱ], 2,6-bis-{3-phenylpyrazol-1-yl}pyridine [L¹Ph], 2,6-bis-{3-[2,4,6-trimethylphenyl]pyrazol-1-yl}pyridine [L¹Mes]) and [M(L²)₂](BF₄)₂ (M=Ni, Co; L²=2-{3-[2,4,6-trimethylphenyl]pyrazol-1-yl}-6-{5-[2,4,6-trimethylphenyl]pyrazol-1-yl}pyridine) have been prepared. Single crystal structure determinations of [M(L¹H)₂](BF₄)₂ (M=Ni, Co) and solvates of [Ni(L¹Mes)₂](BF₄)₂, [Co(L¹Mes)₂](ClO₄)₂ and [Co(L²)₂](BF₄)₂ all show six-coordinate metal centres with local near-D_2d symmetry. The L¹Mes and L² mesityl substituents have only a small effect on the MN{pyrazole} (M=Ni, Co) bond lengths in these compounds. The d–d spectra of the complexes show that L¹Mes is a significantly better donor ligand than L¹H, L¹Prⁱ or L¹Ph, and that L¹Prⁱ is a weaker ligand than might be expected purely on inductive grounds. A combination of UV–Vis/NIR, EPR, NMR and magnetic measurements have demonstrated that all the Co(II) compounds are high-spin in the solid state and in solution at 290 K.