Nickel Perchlorate Research Articles

The comparison of mononuclear and binuclear nickel complexes in their synthesis and catalytic performance of styrene oxidation

The synthesis, characterization, and catalytic activity of four new nickel hydrazone complexes: [NiL2] (1), [Ni(HL)2]·2ClO4·3H2O (2), [Ni2L2(NCS)2(H2O)2]·2H2O (3) and [Ni2L2(NCNCN)2(CH3OH)2] (4) were reported here. HL was obtained by mixing 2-acetylpyridine, 2-aminobenzohydrazine, and methanol together. Complexes 1–4 were synthesized using HL and nickel perchlorate as the main raw materials, methanol as the solvent, and different auxiliary materials. The four complexes were characterized by FT-IR, UV–Vis, and 1H NMR, and their structures were further confirmed by X-ray single crystal diffraction. The impact of the four complexes on styrene oxidation was assessed by employing H2O2 as the oxidant. Investigations revealed that each complex demonstrated effective catalytic functions. Catalytic activity parameters, such as the ratio of substrate to oxidant, temperature, reaction time, catalyst dosage, solvent dosage, and solvent properties, as well as the effect of acid and base additives, were optimized to obtain better conversion of styrene. In particular, the different catalytic performance between mononuclear and binuclear nickel complexes was compared, and a possible mechanism was proposed.

Reactions of 1-Vinyl-4,5-dihydro-1H-benzo[g]indole with Nitrones in Presence of Nickel(II) Perchlorate

Reactions of 1-Vinyl-4,5-dihydro-1H-benzo[g]indole with Nitrones in Presence of Nickel(II) Perchlorate

Nickel-Catalyzed Regiodivergent Asymmetric Cycloadditions of α,β-Unsaturated Carbonyl Compounds

Nickel-Catalyzed Regiodivergent Asymmetric Cycloadditions of α,β-Unsaturated Carbonyl Compounds

Synthesis, crystal structure and antibacterial activity of four mononuclear Schiff base complexes of copper(II) and nickel(II)

Three mononuclear copper(II) complexes, viz. [CuL1] (1), [CuL2] (2), [CuL3] (3), and one nickel(II) complex, viz.[NiL3] (4) where H2L1 = 3,3′-{(methylazanediyl)bis[(propane-3,1-diyl)azanylylidenemethanylylidene]}bis(4-bromophenol), H2L2 = 2,2′-[1,2-phenylenebis(azanylylidenemethanylylidene)]bis(4-bromophenol) and H2L3 = 3,3′-{(methylazanediyl)bis[(propane-3,1-diyl)azanylylidenemethanylylidene]}bis(4,6-dibromophenol), have been prepared. The syntheses have been carried out by the reaction of copper perchlorate (for 1–3) or nickel perchlorate (for 4) with the corresponding Schiff base in the molar ratio of 1:1. The complexes have been characterized by several physicochemical techniques including single-crystal X-ray diffraction. Structural studies reveal that the complexes 1, 3 and 4 adopt distorted trigonal bipyramidal structures, while 2 adopts a distorted square planar geometry. The antibacterial activity of the complexes and the constituent Schiff bases has been tested against two Gram(+) and two Gram(−) bacteria.

Multinuclear nickel(II) complexes with chiral schiff base ligand

Herein we report three chiral, hierarchal mono-, tetra-, and hexa-nuclear nickel complexes that were formed via controlled self-aggregation based on ancillary ligands H3L1 (2,6-bis[(2,3-dihydro-1H-2-indenol)imine]-4-bromophenol) and H3L2 (2,6-bis[(2,3-dihydro-1H-2-indenol)imine]-4-tert-butylphenol). Stoichiometric control of the metal precursor and ligand strongly influenced the nuclearity of the complexes. Mononuclear [Ni(H2L1)2Na2]·2ClO4(1) complex was obtained in the stoichiometric reaction of ligand H3L1 with nickel perchlorate in the presence of sodium acetate. Tetranuclear [Ni4(L1)2(µ3-OMe)2(µ1,3-OAc)2]·2Na(2) and hexanuclear [Ni6(L2)3(µ6-CO3)(MeOH)5(H2O)]·ClO4 (3) were selectively assembled by the reaction of nickel perchlorate and the ligand in a molar ratio of 1:2 without or with carbonate ions, respectively. The solid-state structures of the complexes were confirmed by single-crystal X-ray crystallography. The photophysical properties of the complexes were explored using UV–visible spectroscopy.

Nickel(II) Complexes with Pentane-2,4-dione Bis(4-allylthiosemicarbazone)

Reaction of pentane-2,4-dione with N-(prop-2-en-1-yl)hydrazinecarbothioamide at a 1: 2 molar ratio in ethanol resulted in the formation of a pyrazole derivative. The latter reacted with nickel perchlorate at a 1: 1 molar ratio to form the nickel complex with pentane-2,4-dione bis(4-allylthiosemicarbazone). The same type of nickel complex was obtained as a result of N-(prop-2-en-1-yl)hydrazinecarbothioamide reaction with pentane-2,4-dione and nickel nitrate at a 2: 1: 1 molar ratio. Antimicrobial, antifungal, antioxidant, and anticancer activities of the obtained compounds were studied.

Polyisocyanopeptide hydrogels: A novel thermo-responsive hydrogel supporting pre-vascularization and the development of organotypic structures

Molecular and mechanical interactions with the 3D extracellular matrix are essential for cell functions such as survival, proliferation, migration, and differentiation. Thermo-responsive biomimetic polyisocyanopeptide (PIC) hydrogels are promising new candidates for 3D cell, tissue, and organ cultures. This is a synthetic, thermo-responsive and stress-stiffening material synthesized via polymerization of the corresponding monomers using a nickel perchlorate as a catalyst. It can be tailored to meet various demands of cells by modulating its stiffness and through the decoration of the polymer with short GRGDS peptides using copper free click chemistry. These peptides make the hydrogels biocompatible by mimicking the binding sites of certain integrins.This study focuses on the optimization of the PIC polymer properties for efficient cell, tissue and organ development. Screening for the optimal stiffness of the hydrogel and the ideal concentration of the GRGDS ligand conjugated with the polymer, enabled cell proliferation, migration and differentiation of various primary cell types of human origin. We demonstrate that fibroblasts, endothelial cells, adipose-derived stem cells and melanoma cells, do survive, thrive and differentiate in optimized PIC hydrogels. Importantly, these hydrogels support the spontaneous formation of complex structures like blood capillaries in vitro. Additionally, we utilized the thermo-responsive properties of the hydrogels for a rapid and gentle recovery of viable cells. Finally, we show that organotypic structures of human origin grown in PIC hydrogels can be successfully transplanted subcutaneously onto immune-compromised rats, on which they survive and integrate into the surrounding tissue. Statement of SignificanceMolecular and mechanical interactions with the surrounding environment are essential for cell functions. Although 2D culture systems greatly contributed to our understanding of complex biological phenomena, they cannot substitute for crucial interaction that take place in 3D. 3D culture systems aim to overcome limitations of the 2D cultures and answer new questions about cell functions.Thermo-responsive biomimetic polyisocyanopeptide (PIC) hydrogels are promising new candidates for 3D cell, tissue, and organ cultures. They are synthetic and can be tailor to meet certain experimental demands. Additionally, they are characterized by strain-stiffening, a feature crucial for cell behaviour, but rare in hydrogels. Their thermos-responsive properties enable quick recovery of the cells by a simple procedure of lowering the temperature.

Synthesis and characterization of two new macrobicyclic salts containing hexahydropyrimidine moieties: experimental and density functional theory studies

Two macrocyclic Schiff base ligands (L1, L2) and their related reduced forms (L3 and L4) have been prepared. In the presence of nickel(II) perchlorate in methanol, the reinforced macrobicyclic salts containing hexahydropyrimidine cation moiety have been developed. Here, it seems that Ni(II) perchlorate acts as oxidizing agent converting methanol to the formaldehyde which in turn bridges two nitrogen atoms of reduced forms of macrocycle producing final products. All Schiff base ligands and their reduced forms together with related salts were characterized by elemental analysis, IR spectroscopy, 1H and 13C NMR, EI-Mass and in the case of [L3′](ClO4) salt by X-ray crystallography. The proposed mechanism for the formation of macrobicyclic ligand [L3′] from the reaction of macrocyclic ligand L3 and formaldehyde has also been studied via density functional theory (DFT).

Investigation on biomolecular interactions of nickel(II) complexes with monoanionic bidentate ligands

Reactions of monoanionic bidentate ligands 5-methylsalicylaldehyde (5-msal), 5-bromosalicylaldehyde (5-brsal), 5-nitrosalicylaldehyde (5-nsal) and 2-hydroxy-1-naphthaldehyde (2-hnap) with nickel perchlorate hexahydrate produced nickel(II) complexes 1–4, respectively. Single crystal X-ray analyses of complexes 1 and 2 confirmed bidentate mode of the ligands with O˄O coordination to give square planar geometry around nickel atoms. Complexes 1–4 showed one quasi-reversible redox peak at cathodic region (−0.67 to −0.80 V) and one redox peak at anodic region (+1.08 to +1.44 V) assignable to the Ni(II)/Ni(I) and Ni(II)/Ni(III) redox couples, respectively. The complexes exhibited good bovine serum albumin (BSA) binding abilities with a maximum binding constant of 1.96 × 105 M−1. The binding of complexes with calf thymus DNA (ctDNA) showed that the binding affinity is consistent with an increase in steric bulk of the ligands. The nuclease activity of the complexes showed efficient oxidative cleavage in the presence of hydrogen peroxide as an oxidizing agent. The complexes showed higher zone of inhibition when screened for antimicrobial activity against bacteria and human pathogenic fungi.

Interaction in the nickel perchlorate–acetamide–perchloric acid–water system at 25°С

Heterogeneous equilibria in the nickel perchlorate–acetamide–perchloric acid–water quaternary system at 25°С were studied by studying solubility. The crystallization regions were determined for the initial solid components, eutonic compositions of the ternary systems constituting the quaternary system, binary compounds of acetamide with nickel perchlorate and perchloric acid, and also two new coordination compounds containing simultaneously nickel perchlorate, acetamide, and perchloric acid: Ni(ClO4)2 · 4CH3CONH2 · HClO4 and Ni(ClO4)2 · 2CH3CONH2 · HClO4.

Copolymerization of Carbon Dioxide with Epoxides Catalyzed by Structurally Well-Characterized Dinickel Bis(benzotriazole iminophenolate) Complexes: Influence of Carboxylate Ligands on the Catalytic Performance.

A series of structurally well-defined dinickel carboxylate complexes based on the RBiIBTP derivatives [RBiIBTP = bis(benzotriazole iminophenolate), where R = 3C for the propyl-bridged backbone and 5C for the 2,2-dimethyl-1,3-propyl-bridged backbone] were synthesized and developed for copolymerization of CO2 and epoxides. The one-pot reactions of nickel perchlorate with the RBiIBTP-H2 proligands and an appropriate amount of carboxylic acid derivatives (CF3COOH or 4-X-C6H4CO2H; X = H, CF3, OMe) upon the addition of triethylamine in refluxing methanol (MeOH) afforded dinuclear nickel dicarboxylate complexes, which could be formulated as either [(RBiIBTP)Ni2(O2CCF3)2] (1 and 2) or [(RBiIBTP)Ni2(O2CC6H4-4-X)2] (3-7). The dinickel monobenzoate complexes [(RBiIBTP)Ni2(O2CPh)(ClO4)(H2O)] [R = 3C (8) and 5C (9)] were prepared by using a similar synthetic route in tetrahydrofuran under reflux with a ligand precursor to metal salt to benzoic acid ratio of 1:2:1 in the presence of NEt3. Recrystallization of neutral nickel perchlorate complex 8 in a saturated MeOH or ethanol (EtOH) solution gave ionic and alcohol-solvated monobenzoate bimetallic analogues [(3CBiIBTP)Ni2(O2CPh)(S)2]ClO4, where S = MeOH (10) and EtOH (11). Single-crystal X-ray crystallography of dinickel analogues 1-11 indicates that the BiIBTP scaffold performs as a N,O,N,N,O,N-hexadentate ligand to chelate two Ni atoms, and the ancillary carboxylate group adopts a bridging bidentate bonding mode. Catalysis for copolymerization of carbon dioxide (CO2) with cyclohexene oxide (CHO) by complexes 1-9 was systematically investigated, and the influence of carboxylate ligands on the catalytic behavior was also studied. Trifluoroacetate-ligated dinickel complex 1 efficiently catalyzed CO2 and CHO with a high turnover frequency (>430 h-1) in a controlled fashion, generating perfectly alternating poly(cyclohexenecarbonate) with large molecular weight (Mn > 50000 g/mol). In addition to CO2/CHO copolymerization, bimetallic complex 1 was found to effectively copolymerize CO2 with 4-vinyl-1,2-cyclohexene oxide (VCHO) or cyclopentene oxide, producing the high carbonate contents of poly(VCHC-co-VCHO)s and highly alternating poly(cyclopentene carbonate)s, respectively. This study also enabled us to compare the catalytic efficiency of using cyclic epoxides with different ring strains or functional groups as comonomers by the dinickel catalyst 1.

Synthesis, crystal structures, hydrogen bonding graph-sets and theoretical studies of nickel (+II) co-ordinations with pyridine-2,6-dicarboxamide oxime

The pyridine-2,6-dicarboxamide oxime, C 7 H 9 N 5 O 2 , was Synthesis and characterises with 1 H NMR and FTIR spectroscopy . The reaction of this ligand with nickel (II) perchlorate yielded green crystals of formula [Ni(C 7 H 9 N 5 O 2 ) 2 ] 2+ ,2[ClO 4 ] - , which crystallized in the monoclinic space group C2/c with a = 14.915(2), b = 0.895(2), c = 8.205(1) A, β = 114.69(1), and Z = 4. The complex consists of discrete cations (+II) and one perchlorate anion, the cations existing in a slightly distorted octahedral complex with bonding through the heterocyclic and oxime nitrogen atoms. The structure is held together through N-H…O, O-H…O and C-H...O hydrogen bonds occurring between the coordinated oxime molecules and the perchlorate counter-ion. Computational investigations of nickel(II) complex are done by using M062X method with 6-31+G(d)(LANL2DZ) basis set in vacuo.

Amine-imine compounds of nickel(II) and copper(II) incorporating 1,2-ethanediamine and 1,3-propanediamine

Reaction with acetone of [M(en)(tmd)](ClO4)2 (en=1,2-ethanediamine, tmd=1,3-propanediamine) for M=Ni(II) forms 7RS-(2,8,8,10-tetramethyl-3,7,11-trimethyltridec-2,10-diene-13-amine)nickel(II) perchlorate with square-planar Ni(II). For M=Cu(II) the reaction forms 5RS,8RS-(15-amino-4,4,9,9,11-pentamethyl-5,8,12-tetraazapentadec-11-ene-2-one)copper(II) perchlorate 0.33 water with a N4O pentadentate ligand. The structures of these products are reported.

Synthesis, characterization and crystal structures of Ni(II) and Cu(I) complexes with the condensation product of 2-(diphenylphosphino)benzaldehyde and 1-hydrazinophthalazine

A square-pyramidal Ni(II) complex (1) with the composition [NiL(HL′)]ClO4·H2O was synthesized in the reaction of nickel(II) perchlorate and 2-[2-(diphenylphosphino)benzylidene]-1-phthalazinylhydrazone (HL). The coordination surrounding the Ni(II) ion consist of a PNN coordinated deprotonated HL ligand and its corresponding oxidation product – phosphine oxide HL′ – coordinated via two nitrogen atoms of the hydrazinophthalazine moiety. The structure of Ni(II) complex 1 was determined by X-ray analysis, IR spectroscopy, elemental analysis and magnetic measurements. In the reaction of copper(II) perchlorate with HL, a binuclear phthalazine bridged Cu(I) complex (2) was obtained with the composition [Cu2(HL)2](ClO4)2·C2H5OH. The structure of Cu(I) complex 2 was determined by X-ray analysis, IR and NMR spectroscopy, elemental analysis and magnetic measurements.

Synthesis, structural characterization and DFT calculation on a square-planar Ni(II) complex of a compartmental Schiff base ligand

Reaction of a symmetric compartmental Schiff-base ligand, (H2L) with nickel(II) perchlorate hexahydrate in 1:1 M ratio in methanol gives rise to a mononuclear nickel(II) compound, NiL (1). The compound has been characterized by C, H, N microanalyses and UV–Vis spectra. The single crystal X-ray diffraction studies reveal a square planar geometry around the Ni(II) center. The compound crystallizes in monoclinic system with space group C2/c with a = 21.6425(6), b = 9.9481(3), c = 13.1958(4) Å, β = 107.728(2)°, V = 2706.16(14) Å3 and Z = 4. Ground state DFT optimization and TDDFT calculations on the ligand and complex were performed to get their UV–Vis spectral pattern.

Syntheses and crystal structures of copper(II) and nickel(II) complexes derived from 2-bromo-4-chloro-6-[(2-methylaminoethylimino)methyl]phenol

A new centrosymmetric mononuclear copper(II) complex [Cu(L)2](ClO4)2 (I) and a new centrosymmetric mononuclear nickel(II) complex [Ni(L)2(MeOH)2](ClO4)2 (II), where L is the zwitterionic ligand 2-bromo-4-chloro-6-[(2-methylammonioethylimino)methyl]phenolate, have been prepared from the Schiff base 2-bromo-4-chloro-6-[(2-methylaminoethylimino)methyl]phenol with copper perchlorate and nickel perchlorate, respectively. The complexes were characterized by elemental analysis, infrared spectra, and single-cyrstal X-ray diffraction (CIF files CCDC nos. 1408054 (I) and 1407973 (II)). Complex I crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 7.7736(4), b = 21.608(1), c = 8.5194(4) A, β = 93.907(2)°, V = 1427.7(1) A3, Z = 2, R1 = 0.0546, and wR2 = 0.1531. Complex II crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 21.324(3), b = 16.821(2), c = 9.425(1) A, β = 90.114(2)°, V = 3380.5(7) A3, Z = 4, R1 = 0.0693, and wR2 = 0.1627. The Cu atom in I is in square planar coordination, and the Ni atom in II is in octahedral coordination.

ChemInform Abstract: Nickel‐Catalyzed Enantioselective Friedel—Crafts Alkylation of Indoles with β,β‐Disubstituted Nitroalkenes.

An enantioselective Friedel–Crafts alkylation of indoles with β,β-disubstituted nitroalkenes was developed by using a nickel(II) perchlorate–bisoxazoline complex as a catalyst. A range of nitroalkenes and indoles participated in this reaction, affording chiral indole compounds bearing all-carbon quaternary stereocenters in excellent yields and with moderate to good enantioselectivities (up to 80% ee).

Thermal Decomposition and Their Kinetics of Nickel(II) and Zinc(II) Perchlorate Complexes with 4-Aminopyridine and Water

Thermal Decomposition and Their Kinetics of Nickel(II) and Zinc(II) Perchlorate Complexes with 4-Aminopyridine and Water

Synthesis, physicochemical properties and in vitro catalytic activity of a dinuclear nickel(II) complex with a N5O-hexadentate ligand: A functional model for phosphohydrolases

The development of artificial nucleases has been stimulated by the realization that hydrolytically active metal complexes may potentially find utility as robust versatile replacements for restriction enzymes in molecular biology research and as nucleic acid-targeting therapeutics. In this regard, a novel unsymmetrical dinucleating ligand HL (where L is the 2-[(4,7-diisopropyl-1,4,7-triazonan-1-yl)methyl]-4-methyl-6-[(pyridin-2-ylmethylamino)methyl]phenolate moiety) with an N5O-donnor set was synthesized and characterized by IR and 1H NMR spectroscopy. The reaction of HL with nickel(II) perchlorate led to the formation of a μ-phenoxo-bridged dinuclear Ni(II) complex, [Ni2(L)(μ-OAc)2]BPh4·H2O (1). Physicochemical measurements (molar conductometry, IR and UV–Vis spectroscopy and electrochemistry) were performed for 1 and these properties are compared with those presented by similar compounds in the literature. ESI-MS measurements in positive and negative modes confirmed the complex composition as well as the presence of tetraphenylborate counterions, based on their mass and isotopic distribution patterns. Potentiometric titration studies of 1 were carried out (CH3CN/H2O 50% v/v) and we probed its acid/base properties, which are crucial to gaining an understanding of the phosphodiester catalytic cleavage mechanism. Finally, the ability of 1 to mimic the functional role of the dinuclear metalloenzymes was evaluated through studies on its reactivity toward the model-substrate bis(2,4-dinitrophenyl)phosphate (2,4-bdnpp). When compared with similar previously described compounds, complex 1 helped to probe the influence of the aromatic/aliphatic N-donor moieties, such as macrocyclic rings, pyridine and imidazole, through their catalytic efficiency parameter (E/Lmol−1s−1).

Nickel-Catalyzed Enantioselective Friedel–Crafts Alkylation of Indoles with β,β-Disubstituted Nitroalkenes

An enantioselective Friedel–Crafts alkylation of indoles with β,β-disubstituted nitroalkenes was developed by using a nickel(II) perchlorate–bisoxazoline complex as a catalyst. A range of nitroalkenes and indoles participated in this reaction, affording chiral indole compounds bearing all-carbon quaternary stereocenters in excellent yields and with moderate to good enantioselectivities (up to 80% ee).