In The Ni Research Articles

A Detailed Resonance Raman Spectrum of Nickel(II)-Substituted Pseudomonas aeruginosa Azurin

Nickel(II) and cobalt(II) derivatives of the blue copper protein Pseudomonas aeruginosa azurin have been studied by resonance Raman (RR) spectroscopy at liquid-nitrogen temperatures. Vibrational assignments for the observed RR bands of Ni(II)-azurin have been made through a study of (62)Ni-substituted azurin. A comparison of Ni(II)-azurin RR spectra with those of the wild type (Cu-containing) protein showed Ni(II)-S(Cys) stretching vibrations, nu(Ni-S)(Cys), at substantially lower frequencies (approximately 360 versus approximately 400 cm(-1), respectively), indicating that the Ni(II)-S(Cys) bond is much weaker than the corresponding Cu(II)-S(Cys) bond. Resonance enhanced predominantly nu(Ni-N)(His) modes indicate that the metal-N(His) bond distances in the Ni(II) derivative are the same as those in native azurin. The vibrational data also confirm a tetrahedral disposition of ligands about the metal in Ni(II)-azurin found in the protein crystallographic structures. As expected, excitation profile measurements on Ni(II)-azurin show that the nu(Ni-S)(Cys) assignable modes give maxima at the 440-nm absorption band, which confirms a S(Cys) --> Ni(II) charge-transfer origin of the 440-nm electronic transition in Ni(II)-substituted azurin.

Electropreparation and characterization of polyNiTSPc films. An EQCM study

Thin films of polyNi(II)tetrasulfophthalocyanine (polyNiTSPc) electrodeposited on a gold electrode by potential cycling in 0.1 M NaOH solutions containing 1 mM Ni(II) tetrasulfophthalocyanine were studied by cyclic voltammetry, electrochemical quartz crystal microbalance and impedance techniques. Both the mass increase due to the electrodeposited film, and the current of the Ni(II)/Ni(III) process in the film, increase monotonically with the number of electrodeposition cycles, a linear correlation existing between these two parameters. AFM micrographs show that the film is rugose and porous, this porosity being confirmed by the fact that the voltammetric features of gold oxide formation and reduction are unaffected by the film. The cyclic voltammogram of the film in a pH 11 carbonate–hydrogencarbonate buffer shows the characteristic anodic and cathodic peaks of the Ni ( II ) ⇔ Ni ( III ) process, with a large mass decrease upon Ni(II) electrooxidation and an equally large mass increase upon Ni(III) electroreduction. The sign of the mass change is compatible with a β-Ni(OH) 2-character of the film. The large slopes of the plots of mass change vs. charge in the Ni(II)/Ni(III) region clearly show that large fluxes of water and/or ions accompany the electron transfer. The fairly low activation energy of Ni(II) electrooxidation, 38 kJ mol −1, is in agreement with the moderately non-Nernstian behaviour of the Ni(II)/Ni(III) process. The super-Nernstian dependence on pH of the peak potentials of the Ni(II)/Ni(III) process indicates that the species involved are non-stoichiometric, similarly to the Ni 1 − x H x (OH) 2 species in nickel hydroxide.

Kinetics of the complexation of nickel(II) with 1,10-phenanthroline and its derivatives in acetonitrile–water mixed solvents

The kinetics of the complexation of Ni(II) with 1,10-phenanthroline(phen), 4,7-dimethyl-1,10-phenanthroline(dmphen), and 5-nitro-1,10-phenanthroline(NO 2phen) in acetonitrile–water mixed solvents of acetonitrile mole fraction x AN = 0, 0.05, 0.1, 0.2 and 0.3 at 288, 293, 298 and 303 K have been studied by stopped-flow method at ionic strength of 1.0 (NaClO 4) and pH 7.4. The corresponding activation enthalpy, entropy, and free energy were determined from the observed rate constants. The complexation of Ni(II) with the three ligands has comparable observed rate constants; in pure water the observed rate constants are (×10 3 dm 3 mol −1 s −1) 2.31, 2.57, and 1.38 for phen, dmphen and NO 2phen, respectively. The corresponding activation parameters for the three ligands are, however, considerably different; in pure water the Δ H ‡/Δ S ‡ (kJ mol −1/J K −1 mol −1) are 44.7/−30.2, 19.5/−114.1, and 32.2/−76.9 for phen, dmphen, and NO 2phen, respectively. The effects of solvent composition on the kinetics are also markedly different for the three ligands. The Δ H ‡ and Δ S ‡ showed a minimum at x AN = 0.1 for phen; for dmphen and NO 2phen, however, maxima at x AN = 0.2 were observed. Nevertheless, there is an effective enthalpy–entropy compensation for the Δ H ‡/Δ S ‡ of all the three ligands, demonstrating the significant effects of the changes in solvation and solvent structure on the complexation kinetics. As the rate-determining step of Ni(II) complexation is the dissociation of a water molecule from Ni(II), the solvent and ligand dependencies in the Ni(II) complexation kinetics are ascribed to the change in solvation status of the ligands and the altered solvent structures upon changing solvent composition.

Transition metal complexes with thiosemicarbazide-based ligands. XLIV. The supramolecular arrangement in the Ni(II) complexes of S-methylisothiosemicarbazide

The reaction of the octahedral complex [Ni(ITSC) 2(NO 3) 2] ( 1) with sodium terephthalate yielded the novel octahedral complex [Ni(ITSC) 2(H 2O) 2](tere) · 2H 2O ( 2), (ITSC = S-methylisothiosemicarbazide, tere = terephthalate dianion). The X-ray structural analysis of the starting and the final compound showed that they have a centrosymmetric octahedral geometry with the NiN 4O 2 chromophore. As a result of the non-covalent intermolecular interactions, molecules of both complexes tend to associate into the characteristic 2D blocks separated by S-methyl moieties. In the case of 2, the terephthalate anions, located between the S-methyl groups, enable the transformation of the 2D into 3D supramolecular structure. The similar structural arrangement is also found in two previously published structures.

Asymmetric synthesis of β-heterocycle substituted l-α-amino acids

A new efficient method of asymmetric synthesis of β-heterocycle substituted l-α-amino acids through the addition of 3-amino-1,2,4-thiodiazole and 5-mercapto-1,2,4-triazoles, containing various substituents at the 3 and 4 positions, to the CC bond of dehydroalanine in the Ni(II) complex of its Schiff base with ( S)-2- N-( N ′-benzylprolyl)aminobenzophenone has been elaborated upon. Under thermodynamic control, the stereoselectivity of the nucleophilic addition exceeded 94%. After acidic decomposition of the reaction mixtures, the corresponding β-heterocycle substituted α-amino acids with high enantiomeric purity (ee > 98.5%) were isolated.

Experimental and Theoretical Studies of the Multistability in the Electroreduction of the Nickel(II)−N3-Complexes at a Streaming Mercury Electrode

Following our earlier experimental and theoretical studies of the self-organization in the Ni(II)−SCN- electroreduction at the streaming mercury electrode we describe analogous phenomena for the azide complexes of nickel(II). The complex electrochemical mechanism of this process is a source of multistability, if the appropriate serial ohmic resistance is present in the electric circuit. In dependence of the solution composition, bistability and tristability in the response of the electric current vs the applied voltage was observed. No spontaneous oscillations were reported for the studied process. The I−E characteristics of the Ni(II)−N3- electroreduction, which exhibits the region of the negative differential resistance (NDR), are the source for the bistable behavior. If the composition of the sample is adjusted so that the current of the Ni(II) electroreduction in the NDR region overlaps significantly with the extra current, originating presumably from the catalytic reduction of azide ions, the second NDR region is also formed, and these complex characteristics are a source of the tristable behavior. The theoretical description of the observed multistable phenomena was made in terms of both the theory of electrode processes at a streaming electrode and standard techniques of nonlinear dynamics. The linear stability analysis led to theoretical bifurcation diagrams similar to the experimental ones. The reported tristability seems to be one of the first experimental examples of such a behavior in electrochemical systems and one of only a few of its manifestations in chemical systems in general.

One-electron oxidized nickel(II)-(disalicylidene)diamine complex: temperature-dependent tautomerism between Ni(III)-phenolate and Ni(II)-phenoxyl radical states.

The one-electron oxidized species of a Ni(II)-phenolate complex has been shown to be in the Ni(II)-phenoxyl radical state at room temperature and the Ni(III)-phenolate state at < -120 degrees C, indicating that the oxidation state is temperature dependent.

Binary and Ternary Complexes Involved in the Systems Methioninehydroxamic Acid - Glycylglycine - Ni(II) or Cu(II) Ions

The formation constants of binary and ternary complexes involved in the systems methioninehydroxamic acid (MX), glycylglycine (GG) and Cu(II) or Ni(II) were determined by pH-metric titration in aqueous solution at an ionic strength (I)= 0.15 M NaCl) and T = 25°C. Ternary species of the type (MX : GG : Ni(II) or Cu(II) : H) = (1 : 1 : 1 : r), (2 : 1 : 1 : r) and (1 : 2 : 1 : r) exist in the pH range ∼3 to ∼10. Differential pulse polarography (DPP) was used to follow complex formation and to study the reduction properties of these metal ions in the presence of MX, and GG. The metal oxidation states were more stabilized in the ternary systems than in the binary systems except for a few Ni(II) systems. Spectral studies in the UV-Vis-nIR were used to monitor the presence of ternary species in the Ni(II) and Cu(II) systems. In addition, EPR studies were also used to record the magnetic properties of the binary and ternary species in the Cu(II) systems.

Ni(III) vs. Ni(II)-thiyl radical: charge-delocalisation in a binuclear Ni(III)Ni(II)-dithiolate complex.

Multi-frequency EPR spectroscopy on 61Ni-labelled samples of [Ni2(L)]3+ confirms extensive charge-delocalisation between the Ni(III) centre and thiolate donors in the Ni(II)Ni(III) complex.

Structural elements of metal selectivity in metal sensor proteins.

Staphylococcus aureus CzrA and Mycobacterium tuberculosis NmtR are homologous zinccobalt-responsive and nickelcobalt-responsive transcriptional repressors in vivo, respectively, and members of the ArsRSmtB superfamily of prokaryotic metal sensor proteins. We show here that Zn(II) is the most potent negative allosteric regulator of czr operatorpromoter binding in vitro with the trend Zn(II)>Co(II)Ni(II), whereas the opposite holds for the binding of NmtR to the nmt operatorpromoter, Ni(II)>Co(II)>Zn(II). Characterization of the metal coordination complexes of CzrA and NmtR by UVvisible and x-ray absorption spectroscopies reveals that metals that form four-coordinate tetrahedral complexes with CzrA [Zn(II) and Co(II)] are potent regulators of DNA binding, whereas metals that form five- or six-coordinate complexes with NmtR [Ni(II) and Co(II)] are the strongest allosteric regulators in this system. Strikingly, the Zn(II) coordination complexes of CzrA and NmtR cannot be distinguished from one another by x-ray absorption spectroscopy, with the best fit a His-3-carboxylate complex in both cases. Inspection of the primary structures of CzrA and NmtR, coupled with previous functional data, suggests that three conserved His and one Asp from the C-terminal alpha5 helix donate ligands to create a four-coordinate complex in both CzrA and NmtR, with NmtR uniquely capable of expanding its coordination number in the Ni(II) and Co(II) complexes by recruiting additional His ligands from a C-terminal extension of the alpha5 helix.

Dlf complexes with uniform coordination geometry: structural and magnetic properties of an LnNi2 core supported by a heptadentate amine phenol ligand.

The synthesis and physical characterization of a series of lanthanide (Ln(III)) and nickel (Ni(II)) mixed trimetallic complexes with the heptadentate (N(4)O(3)) amine phenol ligand H(3)trn [tris(2'-hydroxybenzylaminoethyl)amine] has been accomplished in order to extend our understanding of how amine phenol ligands can be used to coaggregate d- and f-block metal ions and to investigate further the magnetic interaction between these ions. The one-pot reaction in methanol of stoichiometric amounts of H(3)trn with NiX(2).6H(2)O (X = ClO(4), NO(3)) followed by addition of the corresponding LnX(3).6H(2)O salt, and then base, produces complexes of the general formula [LnNi(2)(trn)(2)]X.nH(2)O. The complexes were characterized by a variety of analytical techniques. Crystals of five of the complexes were grown from methanol solutions and their structures were determined by X-ray analysis: [PrNi(2)(trn)(2)(CH(3)OH)]ClO(4).4CH(3)OH.H(2)O, [SmNi(2)(trn)(2)(CH(3)OH)]NO(3).4CH(3)OH.2H(2)O, [TbNi(2)(trn)(2)(CH(3)OH)]NO(3).4CH(3)OH.3H(2)O, [ErNi(2)(trn)(2)(CH(3)OH)]NO(3).6CH(3)OH, and [LuNi(2)(trn)(2)(CH(3)OH)]NO(3).4.5CH(3)OH.1.5H(2)O. The [LnNi(2)(trn)(2)(CH(3)OH)](+) complex cation consists of two octahedral Ni(II) ions, each of which is encapsulated by the ligand trn(3)(-) in an N(4)O(2) coordination sphere with one phenolate O atom not bound to Ni(II). Each [Ni(trn)](-) unit acts as a tridentate ligand toward the Ln(III) ion via two bridging and one nonbridging phenolate donors. Remarkably, in all of the structurally characterized complexes, Ln(III) is seven-coordinate and has a flattened pentagonal bipyramidal geometry. Such uniform coordination behavior along the whole lanthanide series is rare and can perhaps be attributed to a mismatch between the geometric requirements of the bridging and nonbridging phenolate donors. Magnetic studies indicate that ferromagnetic exchange occurs in the Ni(II)/Ln(II) complexes where Ln = Gd, Tb, Dy, Ho, or Er.

Structural analysis and sheep pituitary receptor binding of GnRH and its complexes with metal ions

Binding of GnRH and its metal complexes to a sheep pituitary receptor have been investigated showing that Cu(II)–GnRH complex is more effectively bound to the receptor than the metal-free ligand, while Ni(II) and Co(II) complexes are less effective than the metal-free GnRH. Earlier studies have explained reasonably well the complex formation with cupric ion, while in this work extensive 1H NMR measurements have been performed for free gonadotropin-releasing hormone (GnRH) and its complexes with Ni(II) in DMSO (dimethyl sulfoxide) solution. This study shows the high order of organization of the metal-free peptide in DMSO solution with two structured ‘domains’ whose relative orientation is modulated by the mobility of the central glycine. Furthermore, theoretical calculations were performed for the Ni(II)–GnRH complex. The data obtained in this work supports previous studies on the co-ordination of Ni(II) ions with GnRH in aqueous solutions at high pH [J. Inorg. Biochem. 33 (1988) 11] and suggest an experimental procedure to reproduce high pH in DMSO solution. In the Ni(II) complex, the metal ion was found to co-ordinate with four nitrogen atoms inducing a well definite arrangement of aromatic side-chains and a rigid backbone structure.

HBFF-SVD Force Field Treatment of Ni(II) Porphine: Important Long Range Cross Terms

A systematic exploration of the importance of cross terms in the Ni(II) porphine force field is reported. Several force fields of varying complexity were generated using a modification of the Hessian-biased singular value decomposition (HBFF-SVD) approach originally developed by Goddard et al. The X-ray crystal structure, a B3LYP/6-31G(d,p) Hessian matrix, and experimental vibrational frequencies were used. The diagonal-only force field is inadequate for reproducing experimental frequencies. As anticipated, inclusion of 1,2 and 1,3 cross terms significantly improves results (total rms error 14.6 cm-1; in-plane rms error = 12.0 cm-1). The longer range terms in a complete, in-plane, force field improve performance dramatically (in-plane rms error = 4.8 cm-1). A total of 83 long range interaction constants have values ≥10 kcal/(mol geom-unit), and 5 are greater than 20 kcal/(mol geom-unit). For example, 1,6- and 1,9-(Cα−Cm)−(Cα−Cm) stretch−stretch, 1,4-(Cα−N)−(Cα−Cm), and 1,4-(Cβ−Cβ)−(Cα−N−Cα) stretch−bend interactions are large and positive. Coupling in- and out-of-plane motions (TORX) enhances out-of-plane accuracy. Though isotopomer data were omitted from the optimization, the HBFF-SVD force fields reproduce these data with high fidelity. Finally, the HBFF-SVD force fields are compared in detail to previous normal-mode analysis and scaled quantum mechanics studies of Ni porphine.

Structures and properties of 6-aryl substituted tris(2-pyridylmethyl)amine transition metal complexes

A series of metal(II) complexes of [6-(2′,5′-dimethoxyphenyl)-2-pyridylmethyl]bis(2-pyridylmethyl)amine (L) have been prepared. X-Ray crystal structures have been determined for L and its metal(II) chloride complexes for Mn, Fe, Co, Ni, Cu and Zn and the results compared. The preparation and crystal structure of the unusual carbonato-bridged copper-tetramer [Cu4(L)4(CO3)2][BF4]4·5.2H2O is also described. The solution-state structures of the complexes are deduced from their physicochemical and spectroscopic properties. The Zn(II) complex, [ZnCl2(L)], shows inversion about the ligand amine group on the NMR timescale — results from a variable temperature NMR study are presented and allow estimation of the barrier to amine inversion as 56 ± 0.5 kJ mol−1. Overall, it is found that the intramolecular steric interactions introduced by substitution of the tris(2-pyridylmethyl)amine (tpa)-skeleton by a single 6-aryl group result in significant changes to the structures and properties of the resulting metal complexes: in particular the aryl-substitution in L causes (i) a weaker ligand-field compared to tpa favouring high-spin complexes, (ii) a tendency toward lower coordination numbers, and (iii) hemilability in the Ni(II) and Cu(II) complexes — the aryl-substituted leg of the ligand (L) is coordinatively labile.

Conformational control of oxidation sites, spin states and orbital occupancy in nickel porphyrins

Ni(II) porphyrin π cation radicals are known to undergo an internal electronic isomerization to L2Ni(III) cations upon complexation with ligands (L). Additional examples of the Ni(II) to Ni(III) conversion are presented for flexible, 'planar' NiOEP (2,3,7,8,12,13,17,18-octaethylporphyrin) and NiT(Pr)P (5,10,15,20-tetra-n-propylporphyrin) in which the Ni(III) orbital occupancy, dz2 or dx2-y2, is determined by the ligand field strength of the axial ligands (pyridine, imidazole, or cyanide). In contrast to these results, the nonplanar NiOETPP (2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetraphenylporphyrin), which is easily oxidized because of its saddle-shape, yields a complex postulated to be a high spin Ni(II) π cation radical, based on crystallographic and optical data for (imidazole)2NiOETPP+ClO4-, in which the electron of high spin Ni(II) in the dx2-y2 orbital is antiferromagnetically coupled to the unpaired electron of the porphyrin radical leaving one electron in the Ni(II) dz2 orbital, i.e. a pseudo Ni(III). The sterically encumbered, nonplanar NiT(t-Bu)P (5,10,15,20-tetra-tertiary-butylporphyrin) yields Ni(III) complexes when ligated by pyridine, imidazole or cyanide, but in all cases only the Ni(III) dz2 orbital is occupied as evidenced by EPR spectroscopy. This anomalous chemistry is attributed to the fact that the macrocycle of NiT(t-Bu)P is so sterically constrained that it cannot readily expand to accommodate the longer equatorial Ni—N distances required by population of the dx2-y2 orbital in Ni(III) or high spin Ni(II). Further support for this postulate derives from NiD(t-Bu)P (5,10-di-tertiary-butylporphyrin) which is less sterically constrained and in which the Ni(III) dx2-y2 orbital is indeed occupied upon complexation with cyanide. These results thus illustrate the significant effects that the conformations, plasticity or rigidity of Ni porphyrin macrocycles can have on sites of oxidation (metal or porphyrin), spin states (low spin Ni(III) or high spin Ni(II)), and orbital occupancies (dz2 or dx2-y2 in Ni(III)).

A high magnetic field effect on the M(II)-substituted magnetite formation (M=Ni, Mn, Co) in the wet process

The M(II)-substituted magnetite (M=Ni, Co and Mn) formation in the wet process in a high magnetic field from 0 to 8 T generated by a superconducting magnet has been studied at the iron ion concentration of 1500 mg/l and the Fe(II)/Fe(III) mole ratios ( R f) of 1 2 and 2 1 . The particle size of the M(II)-substituted magnetite was about 12 nm at R f = 2 1 and about 7 nm at R f = 1 2 . The Ni(II) content of the Ni(II)-substituted magnetite at R f = 2 1 was lower than that at R f= 1 2 . In the Ni(II)-substituted magnetite, the lattice parameter increases with an increase in the magnetic field from 0 to 8 T, indicating that high magnetic fields enhance the formation of the Ni(II)-substituted magnetite (solubility enhancement of Ni(II) to magnetite). Also, the lattice parameter of the Co(II)-substituted magnetite decreased with the increasing magnetic field, however, an increase in the lattice parameter was not found in the Mn(II)-substituted magnetite. The presence of large amounts of vacancies was found in the Ni(II)-substituted magnetite formed in high magnetic fields by XRD and atomic absorption analysis. This result is supported by the experimental result in which the magnetite formed in a high magnetic field tends to adsorb Ni(II) in a high magnetic field, and results in the higher incorporation of Ni(II) into the spinel structure.

Structural characterization of a paramagnetic metal-ion-assembled three-stranded alpha-helical coiled coil.

A helical peptide designed to present an all-leucine core upon folding has been shown to exhibit concentration-dependent helicity and to exist as an ill-defined equilibrium population of oligomers. In marked contrast, an identical peptide covalently modified with a 2,2'-bipyridyl group at the N terminus forms a stable three-stranded parallel coiled coil in the presence of transition metal ions. We have employed paramagnetic Ni(2+) and Co(2+) ions to stabilize the trimeric assembly and to exploit their shift and relaxation properties in NMR structural studies. We find that metal-ion binding and helix-bundle folding are tightly coupled. Surprisingly, the three-helix bundle exhibits a dynamic N-terminal region, and a well-structured C-terminal half. The spectra indicate the presence of a dual conformation for the bundle extending from the N terminus to residue 12. The structure of the two isomeric forms has been ascertained from interpretation of NOEs in the Ni(II) complex and (1)H pseudocontact shifts in the Co(II) complex. Two different facial isomers with distinct susceptibility tensors were identified. The bulky leucine side chain at position 3 in the peptide chain appears to play a role in the conformational variation at the N terminus.

Nickel(II) complexes of amino acids in comparison with the cobalt(III) analogues: interesting structural aspects relative to intermolecular hydrogen bonds and chiral recognition

The crystal and packing structures of three racemic compounds with the formula, [Ni(tren)( dl-aminoacidato)]Cl· nH 2O have been investigated, aiming to compare the homochiral–heterochiral assembly process of the nickel(II) chiral complex cations with their well-studied cobalt(III) analogues. Due to the inherent hydrogen bonding donors–acceptors carried by the complex cations, infinite 1-dimensional (1-D) chains are generated by complementary inter-cationic H- bonds in both the Ni(II) and Co(III) analogues, but with different H- bond patterns. In all the Co(III) analogues studied by this group, the cations are linked together via the same pattern and strength of H- bonds which are designated as C6[R 2 1(6)]. They are homochiral, irrespective of the nature of the amino acidato ligands. In the Ni(II) analogues, the cations are linked by H- bonds described as C 2 1(6)[R 2 2(12)]. However, when the side chain of the amino acid is bulkier, the homochiral assembly of the cations becomes ambiguous due to the observed disorder of the asymmetric carbon. Additionally, it is interesting to note that the deprotonated carboxylic group of the amino acid coordinates with Ni(II) and Co(III) in different modes, as a delocalized and localized anion, respectively.

Nickel(II) and Cobalt(II) Complexes with Products of Condensation of 1-Aminonaphthalene, 2-Aminonaphthalenesulfonic-5 Acid, and Aromatic Carbinols

Seven new cobalt(II) and nickel(II) complexes with Schiff's bases were synthesized. The Schiff's bases were prepared by the condensation of 1-aminonaphthalene with carbinols, α-hydroxy-α-phenylacetophenone (L1), salicylaldehyde (L2), and 2-hydroxy-1-naphthaldehyde (L3), and of 2-aminonaphthalenesulfonic-5 acid with 2-hydroxy-1-naphthaldehyde (L4). The compounds were studied by X-ray powder diffraction, thermogravimetry, measurements of magnetic susceptibility, and spectroscopy (IR and diffuse reflectance). The coordination sites of the ligand and their dentate members were determined. A coordination number of four was realized in the Ni(II) and Co(II) complexes with L1–L3, and the complexes with L4 were characterized by a coordination number of six (a dimer with an octahedral environment of each central ion).

Complexation of Nickel(II) with Dioximes in Ni 2 [Fe(CN) 6 ] Gelatin-Immobilized Matrix Implants

The complexation of Ni(II) with α-dioximes, which occurs due to the contact of Ni2[Fe(CN)6] gelatin-immobilized matrix implants with water-alkaline (pH 12.0 ± 0.1) solutions of dimethylglyoxime, α-benzyldioxime, and nioxime (H2L) used as ligands, was studied. It was shown that in each system, the [Ni(HL)2], [Ni(H2L)2]2+, and [Ni(H2L)]2+ coordination compounds were formed, while in the Ni(II)–dimethylglyoxime system at pH > 13, the [NiL(OH2)2] complex was additionally formed.