New complexes of iron(III), cobalt(II), nickel(II) and copper(II) with 2-phenyl-1,2,3-triazole-4-carboxalidene-2-aminophenol

Summary Fe^III, Co^II, Ni^II and Cu^II complexes of a new Schiff base, 2-phenyl-1,2,3-triazole-4-carboxalidene-2-aminophenol (PTCAP), have been synthesized and characterized by elemental analyses, molar conductance and magnetic susceptibility measurements, and by u.v.-vis., i.r. and e.p.r. spectral observations. The studies indicate an octahedral structure for the complexes with the general formula [ML₂] (M = Co^II, Ni^II or Cu^II.; L = PTCAP) or [M′(OH)L₂] (M′ = Fe^III). The i.r. spectra suggest that the ligand acts as a tridentate (NNO) donor towards Co^II, Ni^II and Cu^II, and, in the Fe^III complex, one of the two ligand molecules acts as a bidentate (NO) donor and the other as a tridentate donor. The M?ssbauer spectrum of the Fe^III complex suggests the presence of a spin equilibrium at room temperature. Cyclic voltammograms are also recorded for the Cu^II and Fe^III complexes.     

Synthesis,characterization, theoretical calculations and catalase-like activity of mixed ligand complexes derived from alanine and 2-acetylpyridine

Mixed ligand complexes [M(2-AP)(Ala)Cl _x · mH₂O]nH₂O, where (M = Co^II, Ni^II, Cr^III and Fe^III, 2-AP = 2-acetylpyridine, Ala = alanine, x = 2–3, m = 0–1 and n = 3–5] are synthesized and characterized by elemental analysis, FTIR, UV/Vis., MS, TG, measurements and semi-empirical calculations ZINDO/1 and PM3. The results suggest an octahedral geometry for all isolated complexes. FTIR spectra show that alanine coordinates to the metal ions as a neutral unidentate through the amino nitrogen where 2-acetylpyridine coordinates to the metal ion in a bidentate manner through carbonyl oxygen and pyridyl nitrogen. Semi-empirical calculations have been used to study the molecular geometry and the harmonic vibrational spectra with the purpose to assist the experimental assignment of the complexes. The Fe complex showed significant activity as a catalase-like model.     

Chromium(III), manganese(II), iron(III), cobalt(II), nickel(II) and copper(II) complexes with a pentadentate, 15-membered new macrocyclic ligand

Complexes of Cr^III, Mn^II, Fe^III, Co^II, Ni^II and Cu^II containing a macrocyclic pentadentate nitrogen–sulphur donor ligand have been prepared via reaction of a pentadentate ligand (N₃S₂) with transition metal ions. The N₃S₂ ligand was prepared by [1 + 1] condensation of 2,6-diacetylpyridine with 1,2-di(o-aminophenylthio(ethane. The structures of the complexes have been elucidated by elemental analyses, molar conductance, magnetic susceptibility measurements, i.r., electronic and e.p.r. spectral studies. The complexes are of the high spin type and are six-coordinate.     

Studies on 4-(2-thiazolyl)-1-(2-acetylpyridine)thiosemicarbazone complexes of some bivalent metal ions

Summary Complexes [VO(Htaptsc)SO₄] and [M(Htaptsc)₂Cl₂] [M=Mn^II, Ni^II, Cd^II or Hg^II], Cu(Htaptsc)Cl₂ and [M(Htaptsc)Cl₂] [M=Co^II or Zn^II], and deprotonated compounds Co(taptsc)₂ and [M(taptsc)₂] [M=V^IVO, Mn^II, Ni^II, Cu^II or Zn^II] [Htaptsc=4-(2-thiazolyl)-1-(2-acetylpyridine)thiosemicarbazone] have been characterized by elemental analyses, electrical conductivity and magnetic susceptibility measurements and electronic, e.s.r. and i.r. spectroscopy. The bonding sites of Htaptsc and the bonding and stereochemistry of the complexes are discussed.     

Isonitrosoacetylacetone dithiosemicarbazone complexes of some first row transition metals

Summary Complexes of the potentially tetradentate ligand isonitroso-acetylacetone dithiosemicarbazone (inbtH₂) of formulae [Ti(inbtH₂)Cl₂]Cl₂, [M(inbt)], where M = V^IV O, Mn^II, Ni^II or Zn^II, [M(inbtH₂)X₂], where M = Co^II and X = Cl, or M = Ni^II and X = Cl, Br or I, and [M(inbtH₂)Cl₂]Cl, where M = Cr^III or Fe^III, have been prepared and characterized by physico-chemical and spectroscopic methods. In all the compounds the metal is coordinated by the thiocarbonyl sulphur and imine nitrogen, as revealed by i.r. studies. The n.m.r. spectra of the complexes of Ni^II and Zn^II confirm coordination through nitrogen. Possible structures for the complexes are proposed. The Mössbauer spectrum of the Fe^III complex is discussed.     

Spectral and structural studies of cobalt(II,III), nickel(II), and copper(II) complexes of dehydroacetic acid N4-dialkyl- and 3-azacyclothiosemicarbazones

Co^II,III, Ni^II, and Cu^II complexes of new dehydroacetic acid N4-substituted thiosemicarbazones have been studied. The substituted thiosemicarbazones, N4-dimethyl-(DA4DM), N4-diethyl-(DA4DE), 3-piperidyl-(DApip) and 3-hexamethyleneiminyl-(DAhexim), when reacted with the metal chlorides, produced two Co^II complexes, [Co(DA4DE)Cl₂] and [Co(DAhexim)₂Cl₂]; two Co^III complexes, [Co(DA4DM-H)₂Cl] and [Co(DApip-H)(DApip-2H)]; a paramagnetic Ni^II complex, [Ni(DAhexim)(DAhexim-H)Cl]; three diamagnetic Ni^II complexes, [Ni(DA4DM-H)Cl], [Ni(DA4DE-H)Cl] and [Ni(DApip-H)Cl]; and four Cu^II complexes with the analogous stoichiometry of the latter three Ni^II complexes. These new thiosemicarbazones have been characterized by their melting points, as well as i.r., electronic and ¹H-n.m.r. spectra. The metal complexes have been characterized by i.r. and electronic spectra, and when possible, n.m.r. and e.s.r. spectra, as well as elemental analyses, molar conductivities, and magnetic susceptibilities. The crystal and molecular structure of the four-coordinate Cu^II complex, [Cu(DAhexim-H)Cl] has been determined by single crystal X-ray diffraction and the anionic ligand coordinates via an oxygen of the dehydroacetic acid and the thiosemicarbazone moiety's imine nitrogen and thione sulfur.     

Synthesis,Characterisation and Catalytic Studies of Iron(III), Cobalt(II), Nickel(II) and Copper(II) Complexes Containing N,O Donor Ligands and Triphenylphosphine

A series of new Schiff base complexes of Fe^III, Co^II, Ni^II and Cu^II containing Ph₃P has been prepared and characterised. The Schiff bases have been prepared by the condensation of salicylaldehyde and naphthaldehyde with the appropriate aniline. The complexes have been characterised by analytical, spectral (i.r., electronic, magnetic, e.p.r., ¹H-n.m.r.) and electrochemical studies. The new complexes have been used as catalysts for aromatic coupling reactions. Higher catalytic activity has been observed for Ni^II compared to the other complexes.     

Magnetic properties of biacetyldihydrazone complexes

Summary Magnetic susceptibilities of the biacetyldihydrazone (BdH) complexes [M(BdH)₃](NO₃)₂ (M = Co^II, Ni^II, Cu^II or Zn^II), [Fe(BdH)₃](NO₃)₃, [M(BdH)₃](Ni(dto)₂] (M = Co^II, Ni^II or Zn^II; dto = dithiooxalate), [(BdH)₂Cu(dto)Ni(dto)] and [Fe(BdH)₃]₂[Ni(dto)₂]₃ have been studied in the 4.2–295 K range. Zn^II complexes are diamagnetic, and complexes of Ni^II, Cu^II and Fe^III obey the Curie-Weiss law. The Co^II complexes behave anomalously and the results are interpreted in terms of a high spinlow spin equilibrium.     

The coordination chemistry ofN,N′-ethylenebis(2-acetylpyridine imine) andN,N′-ethylenebis(2-benzoylpyridine imine); two potentially tetradentate ligands containing four nitrogen atoms

Summary New complexes of the general formulae [ML_A(H₂O)₂]-Cl₂ (M=Ni or Cu), [ML_AX₂] (M=Co or Cu; X=Cl or Br), [NiL_ABr₂]·H₂O, [ML_A] [MCl₄] (M=Pd or Pt), [NiL_B(H₂O)₂]Cl₂·2H₂O, [ML_BCl₂] (M=Co, Ni, Cu, Pd or Pt; X=Cl or Br) and [ML_B] [MCl₄] (M=Pd or Pt), where L_A=N,N-ethylenebis(2-acetylpyridine imine) and L_B=N, N-ethylenebis(2-benzoylpyridine imine), have been isolated. The complexes were characterized by elemental analyses, conductivity measurements, t.g./d.t.g. methods, magnetic susceptibilities and spectroscopic (i.r., far-i.r., ligand field,¹Hn.m.r.) studies. Monomeric pseudo-octahedral stereochemistries for the Co^II, Ni^II and Cu^II complexes andcis square planar structures for the compounds [ML_BX₂] (M=Pd or Pt; X=Cl or Br) are assigned in the solid state. The molecules L_A and L_B behave as tetradentate chelate ligands in the Co^II, Ni^II, Cu^II and Magnus-type Pd^II and Pt^II complexes, bonding through both the pyridine and methine nitrogen atoms. A bidentateN-methine coordination of the Schiff base L_B is assigned in the [ML_BX₂] complexes (M=Pd or Pt; X=Cl or Br). The anomalous magnetic moment values of the Co^II complexes are discussed.     

Macrocyclic complexes of transition metals with divalent polyaza units

A new series of 14–16-membered hexaazamacrocyclic complexes [ML¹X₂] and [ML²X₂] (M = Co^II, Ni^II, Cu^II and Zn^II; X = Cl or NO₃) have been synthesized by template condensation of phenylenediamine, primary diamines and formaldehyde solution 35% in MeOH and have been characterized by i.r., 1H-n.m.r., e.p.r., and u.v. spectroscopy as well as by magnetic susceptibility and conductivity measurements. An octahedral geometry has been suggested for all the complexes.     

Studies on the stereochemistry of diphenyl diketone monothio-semicarbazone and its transition metal complexes

Summary The stereochemistry and complexation behaviour of diphenyl diketone monothiosemicarbazone (DKTS) with Cu^II, Co^II, Ni^II, Cd^II, Zn^II, Pd^II, Pt^II, Ru^III, Rh^III and Ir^III have been investigated by means of chemical, magnetic and spectral (i.r., Raman, ¹H- and ¹³C-n.m.r. and electronic) studies. The ligand forms complexes of the M(DKTS)₂ type with Ni^II, Cu^II and Co^II having a distorted octahedral geometry. The absence of a v(M—X) band in the i.r. spectra, coupled with their 1:1 electrolytic conductances, suggests that Ru^III, Rh^III and Ir^III form octahedral complexes of the [M(DKTS)₂]Cl type. A four-coordinate structure involving bridging halides is proposed for the Zn^II, Cd^II, Pd^II and Pt^II complexes, which have relatively low v(M—X) vibration modes.     

Preparation and characterization of some transition metal complexes of benzoic acid hydrazones of 2-aminonicotinaldehyde

Summary Cu^II, Ni^II, Co^II, Zn^II and Pd^II complexes of tridentate Schiff base ligands derived from the condensation of benzoic acid hydrazides with 2-aminonicotinaldehyde have been prepared and characterized. For M=Cu, Ni, Co and Zn the complexes were formulated as [M(ligand)(H₂O)X] (X=Cl, Br), with a distorted octahedral geometry and tridentate Schiff base ligands. The Pd complexes were formulated as Pd(ligand)Cl₂, with square planar geometries and bidentate Schiff base ligands. The e.s.r. spectra of the Cu^II complexes are discussed.     

Transition metal ion directed bimetallic macrocyclic complexes

Template condensation of 1,4-phenylenediamine, formaldehyde, 1,3-diaminopropane and benzil in a 1:4:4:2, molar ratio results in the formation of a new series of binuclear decaazamacrocyclic complexes: dichloro/nitrato [1-phenyl bis(8,9-diphenyl-1,3,7,10,14 pentaazacyclo-pentadeca-7,9-diene) metal (II)], [M₂LX₄](M = MnII, Co^II, Ni^II, CuII and Zn^II, X = Cl or NO₃), which were characterised by i.r., ¹H-n.m.r., e.p.r., u.v–vis. spectral studies, conductivity and magnetic susceptibility measurements. All the complexes show octahedral geometry.     

Studies on 2-aminobenzophenone-2-thenolhydrazone complexes of some bivalent transition metal ions

Summary Complexes having the chemical compositions [VO(Habth)₂SO₄], [M(Habth)₂Cl₂] [M=Co^II, Ni^II, Cu^II or Zn^II) and [M(abth)₂] [M=V^IVO, Co^II, Ni^II, Cu^II or Zn^II) and Habth=2-aminobenzophenone-2-thenoylhydrazone] have been prepared and characterized. The complexes are non-electrolytes. Magnetic moments and electronic, photoacoustic, e.s.r. and i.r. spectra of the complexes are used to establish the stereochemistry and mode of bonding of the hydrazone.     

Transition metal ion complexes of thiosemicarbazones derived from 2-acetylpyridineN-oxide. I. The 4-methyl derivative

Summary TheN-methyl-2-[1-(2-pyridinyl-1-oxide)ethylidene]hydrazinecarbothioamide, HLO4M, has been used to prepare a series of Co^III, Ni^II and Cu^II complexes. Species with two deprotonated LO4M ligands, one LO4M and one HLO4M ligand, two HLO4M ligands and one HLO4M ligand with two small anionic ligands have been isolated. The deprotonated LO4M bonds as a tridentate ligandvia theN-oxide oxygen, the imine nitrogen (N¹ and the sulphur while the HLO4M ligand coordinates primarily as a bidentate ligandvia only the first two atoms listed above. I.r., electronic, mass and e.s.r. spectra have been used to determine the nature of these complexes. One of the more striking differences between these compounds and those prepared with other thiosemicarbazones of 2-acetylpyridine and 2-acetylpyridineN-oxide is that tetrahedral yellow [Ni(HL)X₂] rather than planar brown [NiLX] (X=Cl or Br) solids have been isolated with this ligand. Other differences in the nature of the coordination spheres of the various metal ions occur with this particular ligand when compared to previously studied thiosemicarbazone complexes.NATO Fellow, on leave from Medical Faculty, Istanbul University.     

Complexes of 1-isonicotinoyl-4-benzoyl-3-thiosemicarbazide with manganese(II), iron(III), chromium(III), cobalt(II), nickel(II), copper(II) and zinc(II)

1-Isonicotinoyl-4-benzoyl-3-thiosemicarbazide (IBtsc) and its Cr^III, Mn^II, Fe^III, Co^II, Ni^II, Cu^II and Zn^II complexes have been prepared and characterized by elemental analyses, magnetic susceptibility measurements, u.v.–vis., i.r., n.m.r. and FAB mass spectral data. The room temperature e.s.r. spectra of the Cr^III, Fe^III and Cu^II complexes yield values, characteristic of octahedral, tetrahedral and square-planar complexes, respectively. The Mössbauer spectra of [Fe(IBtsc-H)Cl₂] at room temperature and at 78 K suggest the presence of high-spin Fe^III. The Ni^II, Cr^III and Cu^II complexes show semiconducting behaviour in the solid state, but the Zn^II complex is an insulator at room temperature. IBtsc and its soluble complexes have been screened against several bacteria, fungi and tumour cell lines.     

2-Aminoacetophenone-2-thenoylhydrazone complexes of bivalent 3d metal ions

Summary 2-Aminoacetophenone-2-thenoylhydrazone, Haath, C₄H₃SC(O)NHN=C(Me)C₆H₄NH₂-o, forms complexes with metal(II) salts of empirical compositions [VO(Haath)₂SO₄], [M(Haath)₂Cl₂] [M=Co^II, Ni^II, Cu^II or Zn^II] and [M(aath)₂] [M=V^IVO, Co^II, Ni^II, Cu^II or Zn^II] which have been characterized by elemental analyses, molar conductance, magnetic susceptibility, electronic, e.s.r., i.r. and n.m.r. (¹H and¹³C) spectral studies. X-ray and electron diffraction patterns have been obtained in order to elucidate the structure of the Cu^II complexes. Photoacoustic spectra of powder Ni^II complexes have been recorded and interpreted in the light of u.v./vis. spectra.     

Studies on 2-acetylthiophene-2-furoylhydrazone complexes of 3d-bivalent metal ions

Summary Metal(II) complexes of 2-acetylthiophene-2-furoylhydrazone (HL) of the types [VO(HL)SO₄], [Cu(HL)₂Cl₂(H₂O)], [M(HL)₂Cl₂] [M=Co^II, Ni^II, or Zn^II] and [ML₂(H₂O)₂] [M=Co^II, Ni^II, Cu^II or Zn^II] have been prepared and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility, visible, e.s.r. and i.r. spectral studies. The bonding and stereochemistry of the complexes are discussed.     

Synthesis and characterization of biacetyldihydrazone complexes of cobalt(II), copper(II), nickel(II) and iron(III)

Summary Biacetyldihydrazone (BdH) complexes [M(BdH)₃](ClO₄)₂ (M=Co^IIor Cu^II) and [M(BdH)₃](NO₃)_2,3 (M = Ni^IIor Fe^III) have been prepared and characterized by chemical analysis, conductance measurements, electronic, i.r. and e.p.r. spectral studies and magnetic subsceptibilities measurements. A mononuclear octahedral configuration is proposed for all complexes studied.     

Ligational behaviour of biacetylmonoxime nicotinoyl hydrazone (H2BMNH) towards transition metal ions

Summary The synthesis and characterization of Mn^II, Co^II, Ni^II, Cu^II, Zn^II, Cd^II UO ₂ ²⁺ , Cr^III and Fe^III complexes of biacetylmonoxime nicotinoyl hydrazone (H₂BMNH) are reported. Elemental analysis, molar conductance, magnetic moment and spectral (i.r., visible and n.m.r.) measurements have been used to characterize the complexes. I.r. spectral data show that the ligand behaves in a bidentate and/or tridentate manner. An octahedral structure is proposed for the Mn^II, Ni^II, Cr^III and Fe^III complexes, while a square-planar structure is proposed for both Co^II and Cu^II complexes on the basis of magnetic and spectral measurements.