Iron(II), cobalt(III), nickel(II) and copper(II) chelates of furan and thiophene azo-oximes

Summary Complexes of furan and thiophene azo-oximes with iron(II), cobalt(III), nickel(II) and copper(II) have been prepared and characterised. Iron(II), cobalt(III) and copper(II) complexes are diamagnetic in the solid state. The diamagnetism of the copper(II) chelates is suggestive of antiferromagnetic interaction between two copper centres.¹H n.m.r. spectral data suggest atrans-octahedral geometry for the tris-chelates of cobalt(III). Nickel(II) complexes are paramagnetic, in contrast to the diamagnetism of the analogous complexes of arylazooximes. The electronic spectra are suggestive of octahedral geometry for the iron(II), cobalt(III) and nickel(II) complexes, andD _4h -symmetry for copper(II). Infrared data indicate N-bonding of the oximino-group to the metal ions.     

Synthesis and characterisation of nickel(II), cobalt(II), manganese(II), copper(II), zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) complexes of tridentate dibasic ONO donor Schiff bases derived from 2-benzothiazolecarbohydrazide and salicylaldehyde/2-hydroxy-1-naphthaldehyde

Summary The syntheses of several new coordination complexes of nickel(II), cobalt(II), manganese(II), copper(II), zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) with new Schiff bases derived from 2-benzothiazolecarbohydrazide and salicylaldehyde or 2-hydroxy-1-naphthaldehyde are described. These complexes have been characterised by elemental analyses, electrical conductance, magnetic susceptibility, molecular weight, i.r. and electronic spectra. The Schiff bases behave as dibasic and tridentate ligands coordinating through the ONO donor system and form complexes of the types NiL · 3H₂O, MnL · 2H₂O, CoL · 2H₂O, CuL, ZnL · H₂O, UO₂L · MeOH and MoO₂L · MeOH (where LH₂ = Schiff base). The copper(II) complexes exhibit subnormal magnetic moments indicating the presence of an antiferromagnetic exchange interaction, whereas the nickel(II), cobalt(II) and manganese(II) complexes behave normally at room temperature. Zinc(II), dioxouranium(VI) and dioxomolybdenum(VI) complexes are diamagnetic; the zinc (II) complexes are tetrahedral, the copper(II) complexes are square planar, all the other complexes are octahedral. Thev(C=N),v(C-O),v(N-N) andv(C-S) shifts have been measured in order to locate the Schiff base coordination sites.     

Synthesis of copper(II) and nickel(II) triazacycloalkane complexes

Summary Copper(II) and nickel(II) complexes of triazacycloalkanes (pqr-cy), with p, q, r = 2–6, have been prepared and characterized by means of electronic and i.r. spectroscopy, and by magnetic measurements. With nickel(II) mononuclear octahedral complexes [Ni(pgr-cy)₂](CI0₄)₂ are formed, but for copper(II) mononuclear octahedral complexes were obtained only for 222-cy and 223-cy. The other ligands gave copper(II) complexes of the type [Cu(pgr-cy)CI]CIO₄, [Cu(pgr-cy)OH]ClO₄, Or [Cu(pgr-cy)CI_1/2OH_1/2]ClO₄. The hydroxy complexes have low magnetic moments and binuclear hydroxy bridged structures are proposed.Ligand names: e.g. p = q = r = 2 is 1,4,7-triazacvclononane     

Copper(II), nickel(II) and cobalt(II) complexes of oxaldihydrazide and succindihydrazide Schiff bases with salicylaldehyde ando-hydroxyacetophenone

Summary Polymeric copper(II), nickel(II) and cobalt(II) complexes of the type M₂L where M = Cu^II, Ni^II or Co^II and H₄L = disalicylaldimine oxamide (H₄A), di(o-hydroxyacetophenoneimine)oxamide (H₄B), disalicylaldimine succinamide (H₄C) or di(o-hydroxyacetophenoneimine)succinamide (H₄D), have been synthesized and characterized by analysis, i.r. and electronic spectra and magnetic moment data. Copper(II) complexes and some of the nickel(II) and cobalt(II) complexes are planar while other nickel(II) complexes are distorted octahedral and other cobalt(H) complexes are square pyramidal. Anomalously low magnetic moments of some complexes have been related to M-M interactionsvia oxo-bridge structures.     

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.     

Synthesis and structures of copper(II) and nickel(II) complexes of 1,8-diaza-4-thiaoctane. Characterization of a novel polymeric trigonal bipyramidal copper(II) complex containing both bridging and meridionally coordinated ligands

Summary The synthesis, x-ray structure determination, and spectroscopic properties of nickel(II) and copper(II) complexes of 1,8-diaza-4-thiaoctane (aeaps) are described. [Ni(aeaps)₂](ClO₄)₂ crystallizes in the orthorhombic space group Pbcn witha=10.943(2),b=13.209(2),c=14.798(2)Å, and Z=4. The complex crystallizes as the unsymmetrical facial isomer, with the sulfur atoms incis positions. The copper(II) complex crystallizes in the monoclinic space group Cc, witha=16.041(2),b=9.223(1),c=16.048(3) Å,a=118.65(2)⁰, and Z=4. The copper(II) ion has a trigonal bipyramidal coordination geometry, with one ligand coordinated meridionally, and two bridging ligands in which the thioether is not bound to a metal ion. The structures of these complexes are discussed in terms of the known solution chemistry of this ligand with copper(II) and nickel(II).     

Structural elucidation of manganese(II), iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of a new multidentate dihydrazino quinoxaline derivative

Summary Manganese(II), iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of a new multidentate oxygen-nitrogen donor, bis(N-salicylidene)-2,3-dihydrazino-1,4-quinoxaline (H₂BSDHQ) were prepared and characterised by elemental analysis, conductance, thermal, spectral and magnetic data. H₂BSDHQ deprotonates to give a dibasic ONNO donor set in a trivalent iron(III) complex, which binds to the divalent metal ions in a bis-tridentate fashion, using two monobasic ONN donor sets, and resulting in polymeric complexes. Octahedral geometries are proposed for all these complexes, and preliminary studies show that they possess potential antimicrobial activity.     

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.     

Complexes of Cobalt(II), Nickel(II) and Copper(II) Chloroacetates with Quinoline N-Oxide

Some 1:1 and 1:2 adducts of cobalt(II), nickel(II) and copper(II) chloroacetates with quinoline N -oxide have been isolated by the interaction of the appropriate metal chloroacetate with quinoline N -oxide (QuinNo). The complexes isolated are of 1:1 stoichiometry of formula [M(CH₃_xClxCOO)₂QuinNO] (when M=Co(II), Ni(II); X=1,2 and 3 and when M=Cu(II), X=l and 2) except copper(II) trichloroacetate which yields an adduct of 1:2 stoichiometry of formula[Cu(CCI₃COO)₂(QuinNO)₂]. The adducts isolated are soluble in common organic solvents.     

Synthesis,Characterization and Structure of Bis‐ and Tetrakis‐Aziridine‐Nickel(II) and Copper(II) Complexes

The synthesis and characterization of mononuclear tetrakis‐aziridine nickel(II ) and copper(II ) complexes as well as of a dinuclear bis‐aziridine copper(II ) complex are described. The reactions of anhydrous MCl₂ (M = Ni^II, Cu^II) with aziridine (= az = C₂H₄NH, C₂H₃MeNH, CH₂CMe₂NH) in CH₂Cl₂ at room temperature in a 1:5 and 1:2 molar ratio, respectively, afforded the tetrakis‐aziridine complexes [M(az)₄Cl₂] (M = Ni, Cu) or the dimeric bis‐aziridine complex [Cu(az)₂Cl₂]₂. After purification, all of the complexes were fully characterized. The single crystal structure analysis revealed two different coordination modes. Whereas both nickel(II ) complexes can be classified as showing an elongated octahedral structure, copper(II ) complexes show either an elongated octahedral or a square pyramidal arrangement forming dimers with chlorido bridges in axial positions. Furthermore, the results of magnetic measurements of the nickel(II ) and copper(II ) compounds are presented.     

Complexes of Cobalt(II), Nickel(II) and Copper(II) Chloroacetates with Quinoline N-Oxide

Some 1:1 and 1:2 adducts of cobalt(II), nickel(II) and copper(II) chloroacetates with quinoline N -oxide have been isolated by the interaction of the appropriate metal chloroacetate with quinoline N -oxide (QuinNo). The complexes isolated are of 1:1 stoichiometry of formula (M(CH_3-xCl_xCOO)₂QuinNO) (when M=Co(II), Ni(Il); X=l, 2 and 3 and when M=Cu(II), X=1 and 2) except copper(II) trichloroacetate which yields an adduct of 1:2 stoichiometry of formula[Cu(CCl₃COO)₂ (QuinNO)₃]. The adducts isolated are soluble in common organic solvents.     

Synthesis and spectroscopic studies of metal(II) complexes prepared withN-2-(5-picolyl)-N′-phenylthiourea

Summary The chlorides and bromides of cobalt(II), nickel(II) and copper(II) along with the acetates of the latter two metal ions and copper(II) tetrafluoroborate were used to prepare complexes ofN-2-(5-picolyl)-N-phenylthiourea (5MTUH). 5MTUH coordinates as a bidentate ligand via the pyridyl nitrogen and the sulphur atoms in the cobalt(II) complexes and the compounds isolated with Cu(BF₄)₂ and CuCl₂. Complexes of stoichiometry [Cu(5MTU)X] (X=Br or C₂H₃O₂) appear to have the deprotonated ligand coordinated via the pyridyl andN thioamide nitrogens and the sulphur atom. The nickel(II) complexes involve monodentate 5MTUH with sulphur being the donor atom. A violet, octahedral [Co(5MTUH)₂Cl₂] complex and a blue, tetrahedral [Co(5MTUH)Cl₂] complex have been isolated, but with CoBr₂ only an octahedral complex could be prepared.     

Copper(II), nickel(II) and cobalt(III) complexes of the macrocyclic ligand C-meso-7,14-diphenyl-5,6-butano-12,13-butano-1,4,8,11-tetraazacyclotetradeca-4,11-diene

Summary Metal complexes of the macrocyclic tetraaza ligand C-meso-7,14-diphenyl-5,6-butano-12,13-butano-1,4,8,11-tetraazacyclotetradeca-4,11-diene (L) are described. The copper(II) and nickel(II) complexes, isolated as their perchlorate salts, are 4-coordinate species. Several cobalt(III) complexes,trans-[CoLX₂]⁺(X = Cl^–, Br^–, NO ₂ ^– or N ₃ ^– have also been characterised. The most probable stereochemistry of the ligand in the metal complexes is the C-meso-N-meso arrangements of the chiral centres. The N-meso stereochemistry leads to the bulky phenyl groups lying in equatorial positions. I.r. and d-d spectra are reported for the various complexes described.     

Synthesis and spectral studies of copper(II), nickel(II), cobalt(II) and vanadyl(II) complexes of tridentate Schiff bases of 1,2,3,5,6,7,8,8a-octahydro-3-oxo-N,1-diphenyl-5-(phenylmethylene)-2-naphthalenecarboxamide

Summary Metal(II) chelates of Schiff bases derived from the condensation of 1,2,3,5,6,7,8,8a-octahydro-3-oxo-N,1-diphenyl-5-(phenylmethylene)-2-naphthalenecarboxamide with o-aminophenol (KAAP), o-aminothiophenol (KAAT) or o-aminobenzoic acid (KAAB) have been prepared and characterized. The complexes are of the type [M(N₂X)]₂ for M = Cu^II and M(NX)₂·nH₂O for M = Ni^II, Co^II and VO^II (X = phenolic oxygen, thiophenolic sulphur or carboxylic oxygen; n = 0 or 2). Conductivity data indicate that the complexes are non-ionic. The Schiff bases behave as dibasic tridentate ligands in their copper(II) complexes and as monobasic bidentate ligands in their nickel(II), cobalt(II) and vanadyl(II) complexes. The subnormal magnetic moments of the copper(II) complexes are ascribed to an antiferromagnetic exchange interaction arising from dimerization. Nickel(II) and cobalt(II) complexes are trans octahedral whereas vanadyl(II) complexes are square pyramidal     

Synthesis of unsymmetrical compartmental oxime nickel(II) and copper(II) complexes: spectral, electrochemical and magnetic studies

A new series of binuclear unsymmetrical compartmental oxime complexes (1–5) [M₂L] [M=Cu(II), Ni(II)] have been synthesized using mononuclear complex [ML] (L=1,4-bis[2-hydroxy-3-(formyl)-5-methylbenzyl]piperazine), hydroxylamine hydrochloride and triethylamine. In this system there are two different compartments, one has piperazinyl nitrogens and phenolic oxygens and the other compartment has two oxime nitrogens and phenolic oxygens as coordinating sites. The complexes were characterized by elemental and spectral analysis. Electrochemical studies of the complexes show two step single electron quasi-reversible redox processes at cathodic potential region. For copper complexes E¹ _pc=−0.18 to −0.62 and E² _pc=−1.18 to −1.25 V, for nickel complexes E¹ _pc=−0.40 to −0.63 and E² _pc=−1.08 to −1.10 V and reduction potentials are sensitive towards the chemical environment around the copper and nickel atoms. The nickel(II) complexes undergo two electrons oxidation. The first one electron oxidation is observed around +0.75 V and the second around +1.13 V. ESR Spectra of the binuclear copper(II) complexes [Cu₂L](ClO₄), [Cu₂L(Cl)], [Cu₂L(NO₃)] shows a broad signal at g=2.1 indicating the presence of coupling between the two copper centers. Copper(II) complexes show a magnetic moment value of μ_eff around 1.59 B.M at 298 K and variable temperature magnetic measurements show a −2J value of 172 cm⁻¹ indicating presence of antiferromagnetic exchange interaction between copper(II) centres.     

Bis -(3,5-dimethyl-pyrazolyl-1-methyl)-(3-phosphanyl-propyl)-amine complexes of copper(II), nickel(II), and cobalt(II)

A series of Cu(II), Co(II), and Ni(II) complexes of bis-(3,5-dimethyl-pyrazolyl-1-methyl)-(3-phosphanyl-propyl)-amine C₁₅H₂₆N₅P (1), prepared from 3-aminopropylphosphine and 1-hydroxymethyl-3,5-dimethylpyrazole were characterized. The nature of bonding and the geometry of the complexes have been deduced from elemental analysis, infrared, electronic, ¹H NMR, ³¹P NMR spectra, magnetic susceptibility, and conductivity measurements. The studies indicate octahedral geometry for nickel complex and square pyramidal geometry for copper and cobalt complexes. The EPR spectra of copper complex in acetonitrile at 300 K and 77 K were recorded. Biological activities of the ligand and metal complexes have been studied on Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Aspergillus flavus by well-diffusion method. The zone of inhibition values were measured at 37°C for a period of 24 h. The electrochemical behavior of copper complexes was studied by cyclic voltammetry. Catalytic study indicates the copper complex has efficient catalytic activity in oxidation of amitriptyline.     

Cobalt(II), nickel(II), copper(II) and copper(I) complexes of 2-mercapto-5-methyl-1,3,4-thiadiazole and 2,5-bis(methylmercapto)-1,3,4-thiadiazole

Summary Some cobalt(II), nickel(II), copper(II) and copper(I) complexes of 2-mercapto-5-methyl-1,3,4-thiadiazole (mttz) and 2,5-bis(methylmercapto)-1,3,4-thiadiazole (bmttz) have been prepared and studied by conductometric and magnetochemical methods and by electronic and i. r. spectroscopy. The complexes CoX₂ · 2L (L=mttz, X=Cl, Br or I; L=bmttz, X=Br or I), CoCl₂ · bmttz are pseudotetrahedral, and the complexes NiX₂ · mttz (X=Cl or Br), NiCl₂ · 1.3 bmttz, NiBr₂ · 1.5 bmttz are pseudooctahedral. The complex Co₃(OAc)₂ · 4(mttz-H) · 2H₂O has an undefinite constitution. The polynuclear complexes CuCl₂ · 1.3 mttz and CuBr₂ · 1.2 mttz contain presumably pseudotetrahedral chromophores, the chloride having a subnormal magnetic moment. The CuX₂ · 2 bmttz (X=Cl, Br or NO₃) complexes have a six coordination with bridging ligand molecules. In the CuX · 2 mttz (X=Cl, Br or ClO₄) complexes the anions are coordinated, while in the CuClO₄ · 2 bmttz complex the perchlorate anion is ionically bonded.     

Cobalt(II) and nickel(II) complexes of some nitrogen-oxygen and nitrogen-sulphur ligands

Summary Cobalt(II) and nickel(II) complexes of some nitrogen-oxygen and nitrogen-sulphur ligandsviz., phenylpyruvic acid semicarbazone, (4-methylphenyl)pyruvic acid semicarbazone, phenylpyruvic acid thiosemicarbazone and (4-methylphenyl)-pyruvic acid thiosemicarbazone have been prepared and characterised by elemental analyses, room temperature magnetic moments, infrared and electronic spectral studies. All the complexes have been found to possess the composition M(ligand)₂ and octahedral geometry.     

Synthesis and spectral characterization of zinc(II), copper(II), nickel(II) and manganese(II) complexes derived from <Emphasis Type="Italic">bis</Emphasis>(2-hydroxy-1-naphthaldehyde) malonoyldihydrazone

The present study shows that the reaction of different salts of the same metal with sterically crowded dihydrazone bis(2-hydroxy-1-naphthaldehyde)malonoyldihydrazone (CH₂LH₄) in ethanol/aqueous media gives complexes of different stereochemistry. While the reaction of zinc(II) and copper(II) sulphate with dihydrazone yields tetrahedral complexes, the zinc(II) and copper(II) chlorides give square pyramidal and distorted octahedral complexes, respectively. On the other hand, nickel(II) sulphate and chloride, both give high-spin octahedral complexes with dihydrazone, manganese sulphate gives low-spin octahedral and manganese(II) chloride gives high-spin octahedral complexes. The reaction of these complexes with KF has been investigated. All of the products have been characterized by analytical, magnetic moment and molar conductivity data. The structures of the complexes have been established by spectroscopic studies.     

Cimetidine complexes derived from cobalt(II), nickel(II) and copper(II) salts of polyatomic anions

Summary Cobalt(II), nickel(II) and copper(II) complexes [M(CM)₂]X₂ (X = BF₄ or NO₃) have been prepared with cimetidine (CM). Powder data, molar conductivities, magnetic moments, i.r. and electronic spectra support apseudo-octahedral stereochemistry with MN₂N ₂ S₂ chromophore and tentative structures are proposed for the complexes. Their properties are compared with these of previously prepared complexes.