Inhibitorial effect of the Cu(II) and Ni(II) complexes with polyamines and imidazole derivatives on the Ca,Mg-dependent ATP-ase substrate

The investigation of the inhibitory activity on the Ca,Mg-dependent ATP-ase substrate of some Cu(II) and Ni(II) complexes with polyamines and imidazole derivatives is reported. These results show that the Cu(II) complexes have high inhibitorial effect with the exception of the following very stable compounds: square planar [Cu(N-PropIm)₂(NCS)₂], distorted octahedral [Cu(bipy)₂(NCS)₂] and five coordinate [Cu(Me₆tren)(NCS)] (SCN). The Ni(II) derivatives present a medium inhibitorial activity except to the stable tetrahedral [Ni(N-PropIm)₂(NCS)₂], hexacoordinate [Ni(dpt)(tn)(NCS)] (SCN) and fivecoordinate [Ni(dpt)(tn)]Br₂ and [Ni(Me₆tren)(NCS)] (SCN). An explanation of these conclusions is reported.     

Coordinative flexibility of 1,2-bis[1,4,7-triazacyclonon-1-yl]propan-2-ol in mononuclear and binuclear Ni(II) complexes

Reaction of 1,2-bis[1,4,7-triazacyclonon-1-yl]propan-2-ol hexabromide (T(2)PrOH.6HBr) with Ni(ClO(4))(2)[middle dot]6H(2)O and adjustment of the pH to 7 resulted in the crystallization of pink and blue products from the one reaction mixture. The analytical data and X-ray structure determinations establish compositions corresponding to [Ni(T(2)PrOH)]Br(ClO(4))xH(2)O (pink crystals) and [Ni(2)(T(2)PrO)(OH(2))(3)Br]Br(ClO(4))x2H(2)O (blue crystals). A repeat synthesis of the latter yielded the diperchlorate monohydrate [Ni(2)(T(2)PrO)(OH(2))(3)Br](ClO(4))(2)xH(2)O. In the mononuclear complex, the 2-propanol group connecting the two 1,4,7-trizacyclononane (tacn) rings is protonated, the six nitrogen donors from the T(2)PrOH ligand coordinating to a single Ni(II) centre in a distorted octahedral geometry. In the binuclear complexes and, three coordination sites on each distorted octahedral Ni(II) centre are occupied fac by three nitrogen donors from the one tacn ring, the two metal centres being linked by an endogenous alkoxo bridge. A notable common feature of the two identical cations is that for one Ni(II) centre the remaining two sites are occupied by two water ligands, while in the other a bromo ligand replaces one ligated water. Similar binuclear systems have been recently defined [Zn(2)(T(2)PrO)X(H(2)O)(2)](ClO(4))(2)(X = Cl, Br), two complexes that exhibit coordination asymmetry with one pseudo-octahedral and one pseudo-square pyramidal Zn(ii) centre. The weak antiferromagnetic coupling in and is discussed and compared to di-phenoxo-bridged Ni(II) examples.     

Ni(II) complexes with 8-aminoquinoline derivatives

Some Ni(II) complexes with 5,7-dicloro-8-aminoquinoline (dcaq), 5,7-dibromo-8-aminoquinoline(dbaq) and 5,7-diiodo-8-aminoquinoline(diaq) are described. The compounds are of stoichiometry NiL₂X₂(L= dcaq, dbaq, diaq; X= NO^?₃ and L= dbaq; X= Cl^?, Br^?, I^?, NCS^?) and NiLX₂·H₂O(L= dcaq, diaq; X= Cl^?). The electronic spectra and magnetic susceptibility data at room temperature, are consistent with octahedral geometry for the Ni(II) in each compound. I.r. spectra show the presence of ionic and bridging nitrate groups in the compounds NiL₂(NO₃)₂(L= dcaq, dbaq, diaq) and we assign them polymeric structures. Polymeric structures with bridging chloride are proposed for the compounds NiLCl₂·H₂O(L= dcaq, diaq) and monomeric octahedral structures for NiL₂X₂(L= dbaq; X= Cl, Br, I, NCS).     

Synthesis,characterization, molecular and supramolecular structures of nickel(II) complexes derived from α-diketone and α-ketoaldehyde bisaroylhydrazones

A new series of nickel(II) complexes derived from symmetrical diacetyl bisaroylhydrazones [Ni(L¹-R)] and unsymmetric phenylglyoxal bisaroylhydrazones [Ni(L²-R)] have been prepared and characterized. X-ray crystal and molecular structures of [Ni(L¹-H)], [Ni(L¹-pCH₃O)] and [Ni(L¹-pNO₂)] have been determined. In these complexes, the Ni(II) is in a distorted square planar environment and the aroylhydrazone acts as dinegative tetradentate ligand forming a 5,5,5-tricyclic chelate ring. Reaction of [Ni(L¹-R)] with aqueous ammonia afforded the paramagnetic five coordinate [Ni(L¹-R)(NH₃)] while [Ni(L²-R)] gave the diamagnetic square planar [Ni(L²-R)(NH₃)] complexes. Reaction of [Ni(L¹-R)] complexes with imidazole gave the corresponding paramagnetic octahedral bis(imidazole) adducts. X-ray structures of both [Ni(L¹-H)(HIm)₂] and [Ni(L¹-pNO₂)(HIm)₂] suggest a distorted octahedral structure where the bisaroylhydrazone occupies the basal plane while the two imidazoles occupy the axial sites. The molecular units are associated together forming triple stranded helical chains. With imidazole the [Ni(L²-R)] series gave the corresponding diamagnetic mono(imidazole) [Ni(L²-R)(HIm)] complexes, The X-ray structure of {Ni(L²-pCH₃)(HIm)] suggest square planar arrangement around the Ni(II) where the bisaroylhydrazone acts as dinegative NNO tridentate ligand forming with the Ni(II) a 5,6-bicyclic chelate ring the fourth coordination site is occupied by imidazole nitrogen.     

Metal complexes of pyrimidine-derived ligands—III: Tris-complexes of Co(III), Ni(II) and Cu(II) fluoroborates,perchlorates and iodides with 3,5-dimethyl-1-(4′,6′-dimethyl-2′-pyrimidyl) pyrazole,a potential anti-tumour agent

Tris-complex of Co(II), Ni(II), Cu(II) fluoroborates, perchlorates and iodides with the title ligand conform to the composition M(DPymPz)₃X₂, nH₂O [M = Co(II), Ni(II), Cu(II); X = ClO₄, BF₄ and I, n = 0,2]. Physico-chemical characterisations of the complex species have been made from electronic and vibrational spectra, magnetic susceptibility measurements in the solid state and conductivity measurements in solution. Electronic spectral features together with the corresponding ligand field parameters suggest an overall octahedral environment for the pyrazolyl nitrogen (tertiary) and one of the pyrimidyl nitrogens as bonding sites in forming these complexes while the anion (X) retains its identity (as in free form) in the said species.     

A Ni(II)-Containing Complex: Treatment Activity on Chronic Congestive Heart Failure via Reducing Inflammatory Response in Cardiomyocytes

Journal of Cluster Science - Reaction of Ni(NO3)2 with KSCN and 1,3,5-tris(triazol-1-ylmethyl)-2,4,6-trimethylbenzene (TTTMB) leads to the formation of a new 3D Ni(II) coordination polymer...     

Two new [Ni(tren)2]2+ complexes: [Ni(tren)2]Cl2 and [Ni(tren)2]WS4

Both title compounds, bis­[tris(2‐amino­ethyl)­amine]­nickel(II) dichloride, [Ni(tren)₂]Cl₂, (I), and bis­[tris(2‐amino­ethyl)­amine]­nickel(II) tetra­thio­tungstate, [Ni(tren)₂]WS₄, (II), contain the [Ni(tren)₂]²⁺ cation [tren is tris(2‐amino­ethyl)­amine, C₆H₁₈N₄]. The tren mol­ecule acts as a tridentate ligand around the central Ni atom, with the remaining primary amine group not bound to the central atom. In (I), Ni²⁺ is located on a centre of inversion surrounded by one crystallographically independent tren mol­ecule. In the [Ni(tren)₂]²⁺ cation of (II), the Ni atom is bound to two crystallographically independent tren mol­ecules. The Ni atoms in the [Ni(tren)₂]²⁺ complexes are in a distorted octahedral environment consisting of six N atoms from the chelating tren mol­ecules. The counter‐ions are chloride anions in (I) and the tetrahedral [WS₄]^2? anion in (II). Hydro­gen bonding is observed in both compounds.     

Thin films of metal dibenzotetraaza [14] annulene complexes.: Part 3. Dimerization and alternated dimerizations of γ-substituted Ni complexes

The electrochemical behaviour of some Ni γ-monosubstituted dibenzotetraaza [14] annulene complexes has been investigated. The oxidation in CH₂Cl₂ of the complex containing a 4-carboxybenzyl group leads to the corresponding γ-γ dimer whose electrochemical properties have been studied. The electrode surface can be coated by thin films of this dimer using CH₃CN instead of CH₂Cl₂; however, the resulting modified electrode is poorly stable. The oxidation of the complex containing 1-(4-carboxybenzyl)pyrrole as γ substituent involves γ-γ dimer formation before the formation of a regular polypyrrole film. The film displays reversible electrochemical reduction of the metal centre (Ni(II)/Ni(I)) and two successive oxidations of the macrocycle (Mc/Mc^•+ and Mc^•+/Mc²⁺). The complex containing a bromo(4-carboxybenzyl) group offers an unusual feature in that polymeric films can be obtained following an original procedure based on alternated dimerizations. This is a consequence of the formation of two different dimers obtained by anodic and cathodic processes.     

Synthesis,characterization, and catalytic activity of heterometallic ion-pair Ni/Mn and Ni/Zn complexes

Two new heterometallic compounds, [Ni(bpy)₃][Mn(NCO)₄]·H₂O (1) and [Ni(phen)₃]₂[Zn(NCO)₄]₂·4DMSO·H₂O (2) [bpy?=?2,2′-bipyridine and phen?=?1,10-phenanthroline], have been synthesized and characterized. The structures of 1 and 2 were solved by single-crystal X-ray diffraction analysis. The cationic moieties of [Ni(bpy)₃]²⁺ in 1 and [Ni(phen)₃]²⁺ in 2 show octahedral environments around Ni(II), whereas the anionic groups of [Mn(NCO)₄]^2? in 1 and [Zn(NCO)₄]^2? in 2 exhibit tetrahedral geometry around the Mn(II) and Zn(II), respectively. Both compounds are catalysts in the H/D exchange of salicylaldehyde in DMSO-d₆ which takes place under mild conditions and short reaction time.     

CHROMOTROPIC CHANGES OF Cu(II) AND Ni(II) COMPLEXES WITH N2O2 AND N3O2 SCHIFF-BASE LIGANDS IN THE SOLID PHASE

Abstract

Four new Schiff-base ligands have been prepared from the condensation of 3-formyl-4-hy-droxy-1,8-naphthyridin-2-one with different diamines and a triamine, H₂L_a-H₂L_d. Two series of Ni(II) and Cu(II) complexes with the four ligands were also prepared. The ligands and their metal complexes were characterized by chemical analyses, IR, Far-IR, electronic, ESR and mass spectra as well as magnetic measurements and X-ray diffraction patterns.

Different products for Ni(II) and Cu(II) were obtained in similar reactions with the same metal salt, depending on the nature of the ligand. Different geometries were also obtained depending on the counter anion of metal salt. Thus, violet square-planar Cu(II) complexes were obtained with Cu(OAc)₂. H₂O and green octahedral ones with CuCl₂. 2H₂O, except the reaction with ligand H₂L_d which gave only an octahedral product whether the anion was acetate, chloride or perchlorate. Electronic and ESR spectra were used to differentiate between the two geometries of the Cu(II) complexes. The green octahedral Cu(II) complexes undergo irreversible thermochromism to the violet square-planar complexes except the copper complex of the ligand H₂L_d which did not not show any color change and retained its octahedral geometry. Based on the magnetic moments and thermal analyses, only one Ni(II) complex of the Schiffbase ligand H₂L_c undergoes reversible thermochromism from green (octahedral) to red (squareplanar). The reverse change of the thermal product (red) to the parent complex (green) proceeded on exposure to atmospheric air for a few minutes. On the other hand, Ni(II) complexes of ligands H₂L_a and H₂L_b have stable square-planar geometry and all efforts to add other ligands such as H₂O or pyridine to these complexes failed to yield other products. The corresponding Cu(II) complexes were easily transformed to their octahedral geometry by adding H₂O or pyridine and heating.     

Thermal behavior of Co(II) and Ni(II) hydroxycarboxylate complexes obtained by two original synthesis methods

This paper presents a facile and rapid synthesis route of metallic Ni and Co nanocrystallites at ~150 °C in the mixture composed of the corresponding metal nitrates and 1,3-propanediol, as reducing agent. The metal oxides NiO, CoO, Co₃O₄ nanocrystallites were, also, successfully synthesized by thermal decomposition at 300 °C of the hydroxycarboxylate coordination products, obtained in the redox reaction between 1,3-propanediol and Ni(II) and Co(II) nitrates. The formation of the Ni(II) and Co(II) hydroxycarboxylate complexes depends on the diol which generates the carboxylate anion, the transition metal and the process parameters. Ni(II) and Co(II) nanocomposites were also synthesized by thermal decomposition of the complex combinations formed within the pores of the hybrid silica gels. One of the purposes of the present study was to investigate the phase constitution of the composites obtained in similar synthesis conditions, from Ni(II) and Co(II) complex combinations embedded in silica gels. These gels were submitted to various thermal treatments and the changes occurring during these treatments were described by X-ray diffraction. Thermal analysis is an excellent tool for the study of the processes implied in the formation and decomposition of the Co(II) and Ni(II) carboxylate complexes. X-ray diffraction evidenced the nanometer sized metal and/or metal oxide phases.     

Novel complexes of Co2+, Ni2+, and Cu2+ with N-(phosphonomethyl)aminosuccinic acid

Complexes of Co²⁺, Ni²⁺, and Cu²⁺ with N-(phosphonomethyl)aminosuccinic acid (H₄PMAS) of general formula Na₂MPMAS·nH₂O [M=Co(II), Ni(II), Cu(II), n—number of water molecules] were synthesized. Based on interpretation of diffusion reflectance spectroscopy, structure of all complexes is based on distorted octahedral. Analysis of IR spectra of Co(II), Ni(II), and Cu(II) N-(phosphonomethyl)aminosuccinates demonstrated that metal ions are coordinated to the ligand through nitrogen atom of the imino group, oxygen atoms of the α- and β-carboxyl groups as well as oxygen atom of the phosphonic group of the H₄PMAS. We demonstrated that thermal stability of complexes increases in sequence Cu(II) < Ni(II) < Co(II), obviously as a result of change over from the dimeric to polymeric character of the initial complex. Complete decomposition of ligand occurs at these temperatures and is accompanied by release of H₂O, CO₂, and NO₂. The final products of thermal decomposition of the complexes are mixtures of oxides and phosphates of respective metals.     

Spectral and thermal studies of new Co(II) and Ni(II) hexaaza and octaaza macrocyclic complexes

The macrocyclic complexes of Co(II) and Ni(II) having chloride or thiocyanate ions in the axial position have been synthesized and characterized. These complexes are synthesised by the template condensation of o-phenylenediamine or 2,3-butanedionedihydrazone with the appropriate aldehydes in NH₄OH solution in the presence of the metal ions, Co(II) and Ni(II). The complexes were characterized by spectroscopic methods (IR, UV-Vis and ESR) and magnetic measurements as well as thermal analysis (TG and DTA). The results obtained are commensurate with the proposed formulae. Spectral studies indicate that these complexes have an octahedral structure. From conductivity measurements the complexes are non-electrolytes. The kinetic of the thermal decomposition of the complexes was studied and the thermodynamic parameters are reported.     

Structural and magnetic properties of a complete halide series of Ni(II) complexes with a pyridine-containing 14-membered macrocycle

The complete halide series of Ni(II) complexes containing the tetradentate macrocyclic ligand 3,11-dithia-7,17-diazabicyclo[11.3.1]heptadeca-1(17),13,15-triene (L), was fully characterized by X-ray diffraction. The fluoro, chloro, and bromo complexes are dinuclear species with formula [{Ni(L)}2(mu-X)2]2+ (X = halide), whereas only mononuclear species with formula [Ni(Y)(solv)(L)]n+ (Y = halide or solvent molecule), were obtained with I. To date, the fluoro derivative is the first nonorganometallic coordination compound containing the Ni(mu-F)2Ni core. The magnetic properties of these halo complexes have been studied. Intramolecular interactions were observed in the three dinuclear complexes, being antiferromagnetic in the fluoro derivative and ferromagnetic in both the chloro and bromo ones. The two iodo derivatives are paramagnetic species, as would be expected for mononuclear octahedral Ni(II) complexes. Density functional theory calculations led us to relate the magnetic behaviors of these compounds to the values of the corresponding Ni-X-Ni(i) angle. The analysis of the singly occupied molecular orbitals gave a clear comprehension of the different magnetic exchange interactions found in these Ni(II) complexes.     

Catalytic reactivity of new Ni(II), Cu(II) and Sn(II) complexes for decolorization of indigo carmine in aqueous solution,high efficiency of copper complex

A new Ni(II), Cu(II) and Sn(II) Schiff base complexes were synthesized in this work. The characterization of the new complexes is carried out by elemental analysis, FT‐IR, UV–Visible, ¹H NMR and ¹³C NMR spectroscopy, conductance analysis, magnetic measurements and thermal gravimetric analysis. It was found that the ligand behaves as a dibasic bidentate which coordinated to the metal center through two deprotonated hydroxyl groups to form tetrahedral complex with Ni(II) and octahedral complex with Cu(II). The ligand acts as neutral bidentate through azomethine nitrogen and thiazol sulfur to form octahedral complex with Sn(II). The synthesized complexes are evaluated as catalysts for oxidative degradation of indigo carmine dye using H₂O₂ as oxidant and the efficiency of the catalysts is determined. The copper complex shows the best catalytic action with efficiency 92.17% after 25 min.     

Counterdisproportionation between cationic Ni(II) and phosphine Ni(0) complexes

The interaction of Ni(II) bis-tetrafluoroborate complexes [Ni(Dppe)₂](BF₄)₂ and [Ni(CH₃CN)₆](BF₄)₂ (where Dppe = 1,2-bis(diphenylphosphino)ethane)) with Ni(0) phosphine complexes Ni(Dppe)₂ and Ni(PPh₃)₄ in 1 : 1 mixture of toluene-acetonitrile was studied by the EPR method. The counter-disproportionation was shown to occur in a solution between the cationic Ni(II) complexes and the Ni(0) complexes to give Ni(I) complexes almost in quantitative amounts. The structures of the cationic Ni(I) complexes obtained were found to depend on both the solvent nature and the presence of a free phosphine in a solution.     

Transition metal complexes of furfural and benzil schiff bases derived from S-benzyldithiocarbazate

New nickel(II), copper(II), cobalt(III) and rohdium(III) complexes of two Schiff base ligands formed by condensation of furfural and benzil with S-benzyldithiocarbazate have been synthesized and characterized by elemental analysis and magnetic and spectroscopic measurements. The nickel(II) complexes, Ni(NS)₂ and Ni(ONS)₂ (NS and ONS stand for the uninegatively charged furfural and benzil Schiff bases, respectively) are square-planar and octahedral, respectively. The Cu(NS)Cl complex is paramagnetic with a magnetic moment fo 1.73 B.M. A halogen-bridged dimeric structure is proposed for this complex. The copper(II) complex, Cu(ONS)Cl is diamagnetic, suggesting strong antiferromagnetic interactions between a pair of copper(II) ions in a thiolo sulphur-bridged dimeric or polymeric structure. Cobalt(II) ions are oxidized in the presence of the Schiff bases with the concomitant formation of cobalt(III) complexes of empirical formulae, Co(NS)₃, Co(ONS)₂ClO₄ and Co(ONS)₂Cl, respectively, which are spin-paired and octahedral. The rhodium(III) complex of the furfural Schiff base, Rh(NS)₂Cl is tentatively assigned a halogen-bridged dimeric structre.     

Mn(II), Co(II), Ni(II) and Cu(II) complexes of a tertraaza macrocyclic ligand: Synthesis, characterization and biological screening

Manganese(II), cobalt(II), nickel(II) and copper(II) complexes with 1,5,11,15-tetraaza-21,22-dioxo-tricyclo [19,3,1,I^6,10]-5,10,15-20-dicosatetraene (L), as a new macrocyclicligand, have been synthesized with and characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMF correspond to non-electrolytic nature of Mn(II), Co(II) and Cu(II) complexes, while showing a 1:2 electrolyte for thew Ni(II) complexe. Thus, these complexes may be formulated as [M(L)X₂] and [Ni(L)]X₂ (where M = Mn(II), Co(II) and Cu(II) and X = Cl^- and NO₃ ^-). On the basis of IR, electronic and EPR spectral studies, an octahedral geometry has been assigned for Mn(II) and Co(II), a square planar for Ni(II) and tetragonal for Cu(II) complexes. In vitro ligand and its metal complexes were also screened against the growth of some fungal and bacterial species in order to assess their antimicrobial properties.     

New dinuclear nickel(II) complexes: synthesis, structure, electrochemical, and magnetic properties

The reaction of [NiBr(2)(bpy)(2)] (bpy = 2,2'-bipyridine) with organic phosphinic acids ArP(O)(OH)H [Ar = Ph, 2,4,6-trimethylphenyl (Mes), 9-anthryl (Ant)] leads to the formation of binuclear nickel(II) complexes with bridging ArP(H)O(2)(-) ligands. Crystal structures of the binuclear complexes [Ni(2)(μ-O(2)P(H)Ar)(2)(bpy)(4)]Br(2) (Ar = Ph, Mes, Ant) have been determined. In each structure, the metal ions have distorted octahedral coordination and are doubly bridged by two arylphosphinato ligands. Magnetic susceptibility measurements have shown that these complexes display strong antiferromagnetic coupling between the two nickel atoms at low temperatures, apparently similar to binuclear nickel(II) complexes with bridging carboxylato ligands. Cyclic voltammetry and in situ EPR spectroelectrochemistry show that these complexes can be electrochemically reduced and oxidized with the formation of Ni(I),Ni(0)/Ni(III) derivatives.     

Metal complexes of schiff's base derived from salicoylhydrazine and biacetylmonoxime

Biacetylmonoxime-salicoylhydrazone (BMSH) complexes of the types [Hg(BMSH)Cl₂] and [M(BMSH-H)₂], where M = Cu(II), Co(II), Ni(III), Mn(II), Zn(II), Cd(II) and UO₂(VI), have been prepared and characterized by conventional chemical and physical measurements. The IR spectra show that the ligand usually coordinates via carbonyl oxygen (CO), azomethine nitrogen (CNl) and phenolic OH with replacement of hydrogen by metal ions but acts as a bidentate molecule coordinating through (CO) and (CNl) in the Hg(II) complex. The magnetic and spectral data of the Co(II) and Ni(II) complexes support octahedral stereochemistry, whilst tetragonally distorted octahedral geometry is suggested for the Cu(II) complex.