Cobalt(II), nickel(II) and copper(II) complexes of 4-(sulfonylazido)phenylazopyrazolones

Transition metal complexes of Co^II, Ni^II and Cu^II with 4-(4-azidosulfophenylazo)-5-phenyl-3,4-dihydro-2H-pyrazol-3-oneHL¹, 4-(4-azidosulfophenylazo)-5-methyl-2-phenyl-3,4-dihydro-2H-pyrazol-3-one HL² and 4-(3-azidosulfo-6-methoxyphenylazo)-5-methyl-2-phenyl-3,4-dihydro-2H-pyrazol-3-one HL³ were prepared and characterized by elemental analyses, molar conductances and magnetic susceptibilities and by i.r., electronic and e.s.r. spectral measurements as well as thermal (d.t.a and t.g.a.) analysis. The i.r. spectra indicate that HL acts as a bidentate ligand coordinating via the azo and enolic-oxygen linkages. The electronic spectral data and magnetic moments suggest a tetragonally distorted octahedral geometry for the complexes having the formula ML₂·2H₂O, (M = Co^II, Ni^II and Cu^II), square pyramidal geometry for CuL ₂ ³ H₂O and tetrahedral geometry for CoL ₂ ³ . The X-band e.s.r. spectra of the copper(II) complexes reveal anaxial symmetry for both CuL ₂ ² 2H₂O and CuL ₂ ³ H₂O while CuL ₂ ¹ O is isotropic in the solid state at room temperature. The d.t.a. curves show two exothermic peaks for all three complexes CoL ₂ ³ ,NiL ₂ ³ 2H₂O and CuL ₂ ³ H₂O and one endothermic peak for the latter two aqua complexes.     

Copper(II) and nickel(II) complexes of mono-oxocyclam(5-oxo-1,4,8,11-tetraazacyclotetradecane). Synthetic and potentiometric studies

Summary The macrocyclic mono-oxotetraamine, 5-oxo-1,4,8,11-tetraazacyclotetradecane (mono-oxocyclam=LH) has been prepared by reaction of methyl acrylate with 2,3,2-tetra(1,9-diamino-3,7-diazanonane). The protonation constants of the ligand are log K₁=9.40, log K₂=6.65 and log K₃=2.87 at 25 °C (I=0.1 mol dm^–3 NaClO₄). Detailed potentiometric studies of the interaction of the base with copper(II) and nickel(II) have been carried out. In the pH range 2.5–7.0 two complexes, [CuLH]²⁺ and [CuL]⁺, form; the deprotonated complex being 100% abundant at pH 7. For nickel(II), only [NiL]⁺ forms (log _11–1 = 3.90), the yellow low spin nickel complex reaching its maximum concentration above pH 6. The [CuL][ClO₄] · H₂O and [NiL][ClO₄] 0.5 H₂O complexes have been characterised in the solid state. The nickel(II) complex is square planar with a d-d band at 22625 cm^–1.     

Structural studies of 3-amino-4-(substituted arylazo)-5-(1H)pyrazolone compounds

Summary Transition metal complexes of cobalt(II), nickel(II), copper(II) and palladium(II) with 3-amino-4-(arylazo)-5-(1H)pyrazolones (Aryl=Ph, 4-C₆H₄CO₂H, 4-C₆H₄-OMe, 3-C₆H₄Cl, 3-C₆H₄CO₂H, 3-C₆H₄NO₂, 3-C₆H₄-Me, 3-C₆H₄OH and 2-C₆H₄CO₂H) are discussed. The stoichiometry of the complexes is: 11, 23 Co^II; 11 Ni^II; 11, 21 Cu^II and 12 Pd^II. The investigations suggest rhombic symmetry with 4- or 5-coordinate Co^II, square planar and tetrahedral configuration for Ni^II, tetrahedral Cu^II and square planar for Pd^II complexes. The complexes contain no anions.     

Synthesis of nickel(II) complexes of isatin thiosemicarbazone derivatives: in vitro anti-cancer,DNA binding,and cleavage activities

Six new nickel(II) complexes of thiosemicarbazone Schiff base with isatin moiety [Ni(L1)₂–Ni(L6)₂] were synthesized through reaction of Ni(II) with (Z)-2-(2-oxoindolin-3-ylidene)-N-phenylhydrazinecarbothioamide (L1H), (Z)-2-(5-methyl-2-oxoindolin-3-ylidene)-N-phenylhydrazinecarbothioamide (L2H), (Z)-2-(5-fluoro-2-oxoindolin-3-ylidene)-N-phenylhydrazinecarbothioamide (L3H), (Z)-N-methyl-2-(5-nitro-2-oxoindolin-3-ylidene)hydrazinecarbothioamide (L4H), (Z)-N-methyl-2-(5-methyl-2-oxoindolin-3-ylidene)hydrazinecarbothioamide (L5H), and (Z)-N-ethyl-2-(5-methyl-2-oxoindolin-3-ylidene)hydrazinecarbothioamide (L6H). The structures of the Ni complexes were characterized through elemental analysis, infrared, and mass spectral data. The structure of the NiL2 complex was further characterized through single-crystal X-ray diffraction. The interaction of these complexes with calf thymus (CT-DNA) exhibited high intrinsic binding constants (K_b = 1.4 × 10⁵–2.4 × 10⁶ M^?1), which reflected their intercalative activity toward CT-DNA. This result was also confirmed by viscosity data. Electrophoresis studies revealed that these complexes could cleave the DNA through the oxidative pathway. The in vitro anti-proliferative study establishes the anticancer potency of these compounds against human colorectal carcinoma cell line.     

Thermal Studies of Cobalt(II), Nickel(II) and Copper(II) Complexes of 4-(Sulfonylazido Phenylazo) Pyrazolones

The thermal decompositions of cobalt(II), nickel(II) and copper(II) complexes of4-(3'-sulfonylazido-6'-methoxyphenylazo)-1-phenyl-3-methyl-2-pyrazolin-5-one H(D¹–SO₂N₃) and 4-(4'-sulfonylazido phenylazo)-3-phenyl-3-methyl-2-pyrazolin-5-one H(D²–SO₂N₃) were studied by thermogravimetry. The decomposition in all cases takes place along two stages. The first stage is due to the elimination of water and nitrogen molecules with the formation of tetracoordinate complexes containing nitrene reactive species[M(DSO₂N:)₂]. The second stage represents the decomposition of the material to the metal oxide. The kinetics of the decomposition were examined by using Coats–Redfern, the decomposition in all complexes was found to be first order for the first and second stages. The activation energies and other activation parameters (H^* and S^* and G^*) were computed and related to the bonding and stereochemistry of the complexes.This revised version was published online in November 2005 with corrections to the Cover Date.     

Synthesis, crystal structure and magnetic property of a new 1D molecular material [1-(4′-chlorobenzyl)-4-aminopyridinium](+) bis(maleonitriledithiolato)nickel(-)

A new ion-pair complex, [1-(4′-chlorobenzyl)-4-aminopyridinium](+)bis(maleonitrile-dithiolato)nickel(−),[ClbzPyNH₂][Ni(mnt)₂] (1), has been prepared and characterized. X-ray single crystal structure conforms that the Ni(mnt)₂⁻ anions and [ClbzPyNH₂]⁺ cations of 1 form completely segregated uniform stacking columns with the Ni?Ni distance 3.944 Å in the Ni(mnt)₂⁻ stacking column. The temperature dependence of the magnetic susceptibility reveals that 1 undergoes a magnetic transition, and exhibits ferromagnetic interaction in the high-temperature phase and spin gap system in the low-temperature phase.     

Copper(II), nickel(II) and zinc(II) complexes ofN,N′, N″, N‴-tetra(2-cyanoethyl)-1,4,8, 12-tetra-azacyclopentadecane

Summary Reaction of 1,4,8, 12-tetra-azacyclopentadecance ([15])-aneN₄) with an excess of acrylonitrile gives theN-tetracyanoethylated ligand (L). Several new complexes of this ligand with nickel(II), copper(II) and zinc(II) have been prepared and characterised. The complexes can be formulated [NiL]_n(ClO₄)_2n, [ML](ClO₄)₂ (M=Cu^II and Zn^II), [NiL(NCS)₂], [NiLCl₂], [CuL](NO₃)₂ and [NiL]_n(NO₃)_2n·2H₂O. Spectral, magnetic and conductivity data are reported and possible structures are considered.     

Microwave-assisted synthesis,crystal structures,and in vitro antibacterial studies of zinc(II) and nickel(II) complexes with Schiff bases

The syntheses of a mononuclear zinc(II) complex [ZnCl(L¹)(Amp)] (I) and a mononuclear nickel(II) complex [Ni(L²)(HL²)](BF₄) · 0.5H₂O (II) (HL¹ = 4-methyl-2-[(4-methylpyridin-2-ylimino) methyl]phenol, HL² = 4-methyl-2-[(pyridin-2-ylmethylimino)methyl]phenol; Amp = 2-amino-4- methylpyridine) were prepared under microwave irradiation. The complexes were characterized by a combination of elemental analyses, and IR and electronic spectra. Their structures were further confirmed by single crystal X-ray crystallography (СIF files CCDC nos 1437737 (I), 1437738 (II)). The Zn atom in the monomeric complex I is in tetrahedral coordination. The Ni atoms in the dimeric complex II are in octahedral coordination. Crystals of the complexes are stabilized by hydrogen bonds. In order to evaluate the biological activity of the complexes, in vitro antibacterial against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa was assayed. The complexes have strong activity against Bacillus subtilis.     

Synthesis and structure of (η-cyclopentadienyl)(η-(1-(η-cyclopentadienyl)-2-phenyl-3-methyl-1-nickelaindenyl)nickel - the first analogue of nickelocene with a nickelacyclopentadienyl ring

A new metallacyclic compound (η⁵-cyclopentadienyl)(η⁵-(1-(η⁵-cyclopentadienyl)-2-phenyl-3-methyl-1-nickelaindenyl)nickel was synthesised and characterised. Its molecular and crystal structure was determined by X-ray measurements. It crystallises from hexane:THF mixture in the monoclinic crystal system and the P2₁/c space group. This is the first example of the homometallic metallametallocene of nickel. Like in nickelocene the central nickel atom has 20 valence electrons, so the compound can be regarded as the first nickelacyclic analogue of nickelocene.     

Copper(II) complexes containing chiral substituted 2-(4-isopropyl-4-methyl-4,5-dihydro-1H-imidazol-5-one-2-yl)pyridine ligands: Synthesis, X-ray structural studies and asymmetric catalysis

New chiral N,N-bidentate ligands derived from substituted 2-(4-isopropyl-4-methyl-4,5-dihydro-1H-imidazol-5-one-2-yl)pyridines have been prepared and characterised by means of ¹H, ¹³C NMR spectroscopy and optical rotation. Their Cu(II) complexes were characterized by means of elemental analysis, ¹H NMR spectroscopy and MS. By means of X-ray diffraction, molecular geometry of the complex of 2-(1-methyl-4-isopropyl-4-methyl-4,5-dihydro-1H-imidazol-5-one-2-yl)pyridine with copper(II) chloride was determined. The complex exhibits heterochiral dimeric arrangement of two square pyramids with one terminal and one bridge-forming chlorine atoms and two nitrogen atoms in the bases of the pyramids. The tops of these pyramids are formed by the remaining chlorine atoms. The complexes prepared catalyse the Henry reaction with the overall yields of 41-97% and with the maximum enantioselective excess of 19%.     

Cobalt(II), nickel(II) and copper(II) complexes withN-cyano-N′-methyl-N″(2-[(5-methyl-1H-imidazol-4-yl)methylthio]ethyl)guanidine

Summary N-Cyano-N-methyl-N(2-[(5-methyl-1H-imidazol-4-yl)-methylthio] ethyl) guanidine cimetidine (CM), complexes with Co^II, Ni^II and Cu^II are described. The compounds are of stoichiometry [M(CM)₂]SO₄ · nH₂O [M = Co^II, Ni^II or Cu^II; n = 3,3 or 4, respectively], [M(CM)₂](ClO₄)₂ [M = Co^II or Ni^II], [M(CM)₂]Cl₂ · nH₂O [M=Co^II, Ni^II or Cu^II; n = 1, 2, or 2, respectively] and [Cu(CM)SO₄] · 2H₂O. The electronic spectra of the compounds in solid state, magnetic susceptibilities and i.r. and e.p.r. spectra were studied. Octahedral environments are proposed for the complexes: [M(CM)₂]SO₄·nH₂O, [M(CM)₂](ClO₄)₂, [Ni(CM)₂]Cl₂ · 2H₂O, [Cu(CM)₂]Cl₂ · 2H₂O and [Cu(CM)SO₄] · 2H₂O and a tetrahedral structure for [Co(CM)₂]Cl₂ · H₂O.     

Metal complexes of 1-hydroxy-2,3-dimethyl-4-(3′-methyl-4′-amino-5′-mercapto-1′, 2′, 4′-triazole)-1,4-diaza-1, 3-butadiene with manganese(II), cobalt(II), nickel(II) and copper(II)

Summary Binuclear metal complexes of the type [M(HDDB)-(H₂O)₂]₂: where HDDB=1-hydroxy-2,3-dimethyl-4-(3-methyl-4-amino-5-mercapto-1, 2, 4-triazole)-1,4-diaza-1, 3-butadiene and M=manganese(II), cobalt(II), nickel(II) and copper(II), have been prepared and characterised by elemental and thermal analyses, magnetic measurements, electronic and i.r. spectra. Octahedral geometry around the metal(II) ions is proposed and the crystal field parameters of the cobalt(II) and nickel(II) complexes are also calculated. Fungicidal screening of the complexes has been made aginstHelminthosporium oryzae andFusarium oxysporium.     

Synthesis,structure, and magnetic properties of nickel(II), copper(II), cobalt(II), and zinc(II) 2,2,5,5-tetramethyl-3-imidazolin-1-oxyl-4-(1′-butylidene-2′-oxylates)

Syntheses are reported for the coordination compounds of nickel(II), copper(II), cobalt(II), and zinc(II) with 4-(2 -oxobutylidene)-2,2,5,5-tetramethyl-3-imidazolin-1-oxyl (LH) with the formula NL₂. The central atom in solid NiL₂ has square coordination, while in solution, this atom has distorted tetrahedral coordination. The coordination of the central atom in the other ML₂ is distorted tetrahedral both in the solution and in the solid phase. CuL₂ and CoL₂ in the solid phase feature exchange clusters with ferromagnetic exchange interaction between the unpaired electrons of the paramagnetic sites.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 669–675, March, 1990.The authors thank L. B. Volodarskii for providing a sample of 1-hydroxy-2,2,5,5-tetramethyl-3-imidazoline and a consultation in planning the synthesis of LH, A. M. Atskanov for taking the PMR spectra, E. G. Boguslavskii for taking the EPR spectra, and K. M. Indrichan for taking the mass spectra.     

The relaxation spectra of nickel(II) and cobalt(II) arginine complexes

The temperature-jump method has been used to determine the nickel(II)- and cobalt(II)-arginine complexation kinetics. In the pH range studied, the neutral form of the ligand, HL, is the attacking, as well as the complexed, ligand species. The reactions reported on are of the type where n = 1, 2, 3 and M is Ni or Co. At 25° and ionic strength 0.1M the association rate constants are: for nickel(II) k₁ = 2.3 × 10³(±20%), k₂ = 2.4 × 10⁴(±20%), k₃ = 3.5 × 10⁴(±40%) M^?1 sec^?1; for cobalt(II) k₁ = 1.5 × 10⁵(±20%), k₂ = 8.7 × 10⁵(±20%), k₃ = 2.0 × 10⁵(±40%) M^?1 sec^?1. Arginine binds to metal ions less well than homologous chelating agents due to the electrostatic repulsion arising from the positively charged terminus of the zwitterion. Kinetically, the effect appears in the association rate constants with nickel reactions more strongly influenced than cobalt.     

Transition metal complexes with the thiosemicarbazide-based ligands. Part 12. Synthesis,structure and template reaction of ammine [2,4-pentane-dione S-methylisothiosemicarbazonato(2-)] nickel(II) dihydrate

Summary Ni(NO₃)₂·6H₂O reacts with 2,4-pentanedione S-methylisothiosemicarbazonehydrogen iodide (H₂L·HI) in aqueous solution; addition of ammonia then yields [NiL(NH₃)]·2H₂O, the crystal structure of which has been determined. In the square-planar [NiL(NH₃)]·2H₂O complex, the ligand, 2,4-pentanedione S-methylisothio-semicarbazone occupies three coordination sites with the bonds to the central atoms involving the terminal nitrogen atoms of the isothiosemicarbazide fragment [Ni–N(3) 1.831 Å and Ni–N(2) 1.842 Å] and the oxygen of the 2,4-pentanedione moiety [Ni–O 1.844 Å]. The template reaction of [NiL(NH₃)]·2H₂O with 2,4-pentanedione and triethyl orthoformate, HC(OEt)₃, gave, by heating the complexes, NiL¹ (1) (L¹ = dianion of the quadridentate NNNN macrocyclic ligand 2,10-bis(methylthio)-5,7,12,14-tetramethyl-1,3,4,8,9,11 -hexaazacyclotetradeca-2,4,6,9,12,-14-hexaene) and NiL² (2) (L² = dianion of the quadridentate ONNO ligand 3-acetyl-6-thiomethyl-9-methyl-5,7,8-tri-azadodeca-3,6,9-triene-2,11-dione) presents described.     

Mass-spectrometric investigation of coordination compounds of nickel(II) with radical anions of S-alkyl-1-phenylisothiosemicarbazides

The electron-impact mass spectra of coordination compounds of nickel(II) with the general formula NiL₂, in which the radical anions [C₆H₅N -N-C(SR)=NR¹]^–, where R=CH₃ and R=H(I), R=CD₃ and R=H(II), R=C₂H₅ and R=H(III), and R=CH₃ and R=C₆H₅(IV), serve as the ligands, have been studied. In the mass spectra of compounds I–IV the peaks of the molecular ions have the highest intensity among the organometallic fragments. The initial stage of the fragmentation of [M]^+. is associated with the formation of the rearrangement ions [NiL + H]⁺, [NiL + C₆H₅]⁺, and [NiL + SR]⁺, ions, whose appearance becomes understood, if it is taken into account that the removal of one ligand is accompanied by the impairing of spins and the mass spectra of compounds I–IV is the presence of lines for the [NiL]⁺ ion in them. The dissociative ionization of compounds I–IV is strongly reminiscent of the behavior of ordinary complexes of metals with ligands of the nonradical type. The fragmentation scheme of the molecular ions under the effects of electron impact has been presented and discussed.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 3, pp. 368–371, May–June, 1990.     

Anion-selective receptors based on dinuclear copper(II) and nickel(II) cage complexes of bis-salicylaldimines

The selectivity, anion uptake and exchangeability of anion-binding by metal salt extractants of the form [M₂ L ₂]⁴⁺ have been assessed by the method of anion exchange chromatography in biphasic systems. The order of sulfate-, nitrate-, and chloride-uptake into the solid copper(II) complex as of the dioxime pro-ligand N,N??-dimethyl-N,N??-hexamethylenedi(3-hydroxyiminomethyl-2-hydroxy-5-tert-butylbenzylamine (L ¹ ) is 56, 42, and 16%, respectively, consistent with the relative magnitudes of formation constants for the inclusion complexes, [A?Cu₂ L ¹ ₂] ⁿ⁺ where A = anion, found in UV?Cvis titration studies in a single phase. X-ray structural determination of the bis-benzylimine pro-ligand, N,N??-dimethyl-N,N??-hexamethylenedi-(3-benzyliminomehyl-2-hydroxy-5-tert-butylbenzylamine), nickel(II) sulfato complex [SO₄?Ni₂ L ² ₂]SO₄ reveals the nickel atoms to have a significant tetrahedral distortion, providing more favourable sulfate-alkylammonium interactions within the cage.     

Copper(II) complexes derived from substituted 2,2′-bis-(4-isopropyl-4-methyl-4,5-dihydro-1H-imidazol-5-one) ligands: Synthesis,structure and catalytic activity

New chiral N,N-bidentate 2,2′-bis-(4-isopropyl-4-methyl-4,5-dihydro-1H-imidazol-5-one) ligands have been prepared and characterised by their ¹H and ¹³C NMR spectra and/or optical rotation. The ligands prepared were then tested for their ability to form complexes with copper(II) salts. It was found that the most stable complex is formed from the 2,2′-bis-(4-isopropyl-1,4-dimethyl-4,5-dihydro-1H-imidazol-5-one) ligand and copper(II) chloride. The structure of this complex was determined by means of quantum-chemical computations at the B3LYP or UB3LYP/6-31G(d,p) level. According to the computations, the geometry of the copper atom most resembles a tetrahedral arrangement, which was also confirmed by means of X-ray structural analysis. It was found that the structure of this copper(II) complex does not allow the copper atom to coordinate to additional ligands; therefore, it is catalytically inactive in the asymmetric Henry reaction.     

Synthesis and characterization of new azo-linked Schiff bases and their cobalt(II), copper(II) and nickel(II) complexes

Azo compounds were prepared by the reaction between benzenediazonium chloride and 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid monosodium salt under alkaline conditions. Two new azo-linked Schiff base ligands, 4-(3-methoxysalicylidene)-5-hydroxy-6-(2-hydroxyphenylazo)-2,7-naphthalene disulfonic acid disodium salt (H₂L) and 4-(3-methoxysalicylidene)-5-hydroxy-6-(2-hydroxy-4-cholorophenylazo)-2,7-naphthalenedisulfonic acid disodium salt (H₂L¹), have been synthesized. Also, the new Cu^II, Ni^II and Co^II complexes of the azo-linked Schiff base ligands were prepared and characterized by infrared spectra, UV–Vis, ¹H- and ¹³C-n.m.r., attached proton test (APT) and distortionless enhancement by polarization transfer (DEPT) and atomic absorption spectroscopy, mass spectrocopy, elemental analyses, thermogravimetric analysis, conductivity and magnetic measurements. It was determined that the synthesized ligands were comprised of six-membered rings due to intramolecular hydrogen bonding. The results suggested that condensation of the azo-derivative compounds and o-vanillin in a 1:1 molar ratio produces mononuclear Schiff base ligands with an ONO donor set. Preliminary histological studies were made. Magnetic moment studies showed that all complexes have a tetrahedral configuration.     

Synthesis and crystal structure of nickel(II) complex based on 2-trifluoroacetylcycloalkanone benzoylhydrazones

The reaction of ethanol solutions of benzoylhydrazones of 2-trifluoroacetylcycloalkanones (H₂L) with a solution of nickel(II) acetate in aqueous ammonia in 1 : 1 ratio gave complexes NiL · NH₃ with square structure. The composition and structure of the complexes were determined by elemental analysis, IR and 1H NMR spectroscopy, and X-ray diffraction analysis.