N-Phthaloylglycinate ternary complexes with cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) metal ions and aromatic mono,bi and tridentate amines

Complexes of N-phthaloylglycinate (N-phthgly) and Co^II, Ni^II, Cu^II, Zn^II and Cd^II containing imidazole (imi), N-methylimidazole (mimi), 2,2-bipyridyl (bipy) and 1,10-phenanthroline (phen), and tridentate amines such as 2,2,2-terpyridine (terpy) and 2,4,6-(2-pyridyl)s-triazine (tptz), were prepared and characterized by conventional methods, i.r. spectra and by thermogravimetric analysis. For imi and mimi ternary complexes, the general formula [M(imi/mimi)₂(N-phthgly)₂]·nH₂O, where M = Co^II, Ni^II, Cu^II and Zn^II applies. For Cd^II ternary complexes with imi, [Cd(imi)₃(N-phthgly)₂]·2H₂O applies. For the bi and tridentate ligands, ternary complexes of the formula [M(L)(N-phthgly)₂]·nH₂O were obtained, where M = Co^II, Ni^II, Cu^II and Zn^II; L = bipy, phen, tptz and terpy. In all complexes, N-phthgly acts as a monodentate ligand, coordinating metal ions through the carboxylate oxygen, except for the ternary complexes of Co^II, Ni^II and Cu^II with mimi and Cu^II and Zn^II with imi, where the N-phthgly acts as a bidentate ligand, coordinating the metal ions through both carboxylate oxygen atoms.     

Synthesis and characterisation of some complexes of manganese(II) and iron(II) picrates with heterocyclic amines

Summary Complexes of manganese(II) and iron(II) picrates with various bidentate (L) and monodentate (L) heterocyclic bases have been synthesised; their compositions have been established as [ML₃]A₂ (1), [ML₂ · 2 H₂O]A₂ (2), [ML₆]A₂ (3) and [ML4 · 2 H₂O]A₂ (4), where M = Fe^II and Mn^II, L = 2,2-bipyridyl (bipy) and 1,10-phenanthroline (phen) in (1), A = picrate anion; M = Mn^II, L = bipy and phen in (2); M = Fe^II, L = pyridine (py), 4-picoline (4-pic) and 3-picoline (3-pic) in (3); M = Mn^II, L = py, 4-pic, quinoline (quin) and 2,6-lutidine (2,6-lut) in (4) and also M = Fe^II, L = quin and 2,6-lut.     

Cobalt(II), nickel(II) and copper(II) complexes of bidentate bibenzimidazoles

Summary Complexes of cobalt(II), nickel(II) and copper(II) with novel bidentate bibenzimidazoles, [M(L-L)Cl₂], where L-L are methylenebis(1, 1-benzimidazole), methylenebis(2, 2-benzimidazole) and dimethylenebis(2, 2-benzimidazole) are described and characterized by different physical measurements. The four coordinate complexes have distorted tetrahedral or square coplanar structures. The bridging entity between the two donor groups apparently influences the ligand field strength and the ligands occupy a higher position than that of benzimidazole in the spectrochemical series.     

Preparation and structure of cobalt(II), nickel(II), copper(II) and zinc(II) complexes with 3-amino-5-(α/β)pyridyl-1, 2, 4-triazoles

Summary Complexes of bidentate 3-amino-5-()-pyridyl-1,2,4-triazole (L¹) and 3-amino-5-()-pyridyl-1, 2, 4-triazole (L²) of composition [ML¹Cl₂·H₂O], [ML²Cl₂·H₂O], [ML ₃ ^2/1 Cl₂] and [ML ₃ ^2/2 Cl₂] [M=Co^II, Ni^II, Cu^II, M=Zn^II] have been prepared and characterized by elemental analyses, i.r., u.v./visible, e.s.r. spectra, magnetic moments and molar conductances.     

Cobalt(II), nickel(II) and copper(II) complexes of 5-(2-carboxyphenylazo)-2-thiohydantoin

A new series of hexacoordinate cobalt(II), nickel(II) and copper(II) complexes of 5-(2-carboxyphenylazo)-2-thiohydantoin HL having formulae [LM(OAc)(H₂O)₂] · nH₂O (M = Co^II, Cu^II and Ni^II), [LMCl(H₂O)₂] · nH₂O (M = Co^II and Ni^II), [LCuCl(H₂O)]₂ · 2H₂O, [LCu(H₂O)₃](ClO₄) and [LCu(HSO₄)(H₂O)₂] were isolated and characterized by elemental analyses, molar conductivities and magnetic susceptibilities, and by i.r., electronic and e.s.r. spectral measurements, as well as by thermal (t.g. and d.t.g.) analyses. The i.r. spectra indicate that the ligand HL behaves as a monobasic tridentate towards the three divalent metal ions via an azo-N, carboxylate-O and thiohydantoin-O atom. The magnetic moments and electronic spectral data suggest an octahedral geometry for Co^II complexes, distorted octahedral geometry for both Ni^II and Cu^II complexes with a dimeric structure for [LCuCl(H₂O)]₂ · 2H₂O through bridged chloro ligands. The X-band e.s.r. spectra reveal an axial symmetry for the copper(II) complexes with unsymmetrical M_s = ± 1 signal and G-parameter less than four for the dimeric [LCuCl(H₂O)]₂ · 2H₂O. The thermogravimetry (t.g. and d.t.g.) of some complexes were studied; the order and kinetic parameters of their thermal degradation were determined by applying Coats–Redfern method and discussed.     

New bis-macrocyclic complexes with transition metal ions

Template condensation of benzidine, formaldehyde, ethylenediamine or 1,3-diaminopropane, metal salt and 1-phenyl-1,3-butanedione or 2,3-butanedione in a 1:4:2:2 molar ratio results in the formation of two new series of binuclear pentaaza macrocyclic complexes: dichloro[1,1-phenylbis(7-methyl-9-phenyl-1,3,6,10,13-pentaazacyclotetradeca-6,9-diene) metal(II)], [M₂LCl₄] (M = Co^II, Cu^II, Fe^III and Zn^II) and dichloro[1,1-phenylbis(8,9-dimethyl-1,3,7,10,14-pentaazacyclopentadeca-7,9-diene) metal(II)], [M₂LCl₄] (M = Ni^II, Co^II, Cu^II and Cd^II). Both series were characterized by i.r., ¹H-n.m.r., u.v.–vis. spectral studies, conductivity and magnetic susceptibility measurements.     

Synthesis and magnetic properties of trinuclear copper(II) complexes bridged by dimethylglyoximate groups

Summary New three Cu^II-Cu^II-Cu^II homotrinuclear complexes have been synthesized, namely [Cu(dmg)₂{CuL}₂](ClO₄)₂ [L = 5-nitro-1,10-phenanthroline (5-NO₂-phen), 4,4-dimethyl-2,2-bipyridiine (DMbpy), tetramethylenediamine (TMDA) and dimethylglyoximate ion (dmg)^2-]. The magnetic susceptibilities of complexes (1) (L = 5-NO₂-phen) and (2) (L = DMbpy) were measured in the 4.2–300 K range, giving the parameters,J = -335cm^-1 (1) andJ= -327.5cm^-1 (2). The results demonstrate a very strong antiferromagnetic exchange interaction between the adjacent copper(II) ions.     

Synthesis and characterization of copper(II), nickel(II) and cobalt(II) complexes with novel thiourea derivatives

A novel series of thiourea derivatives, namely, N,N-diphenyl-N-(4-phenyl-benzoyl)thiourea (HL¹), N,N-diphenyl-N-(4-chloro-benzoyl)thiourea (HL²) and N,N-di-n-propyl-N-(4-chloro-benzoyl)thiourea (HL³), and its metal complexes has been prepared and characterised by elemental analysis, i.r. spectroscopy, ¹H-n.m.r. spectroscopy, mass spectrometry and single crystal X-ray diffraction. The ligand coordinates to Ni^II, Cu^II and Co^II in a bidentate manner yielding essentially neutral complexes of the type cis-[ML₂]. N.m.r. spectra and single crystal X-ray diffraction analysis revealed the presence of a distorted tetrahedral coordination ML₂ complex.     

Preparation and electrochemical study of manganese(II) macrocycles containing terpyridine

The macrocycle, L, prepared by template condensation of bis-6,6-(-methylhydrazino)-4-phenyl-2,2:6,2-terpyridine with glyoxal, forms a stable crystalline Mn^II complex, [Mn(L)(H₂O)₂][PF₆]₂, which has been used as a starting material for electrochemical studies on a series of seven coordinate Mn^II complexes [Mn(L)X₂]²⁺ (X = pyridine, 4-cyanopyridine, 4-aminopyridine, 4-dimethylaminopyridine, pyrazine, imidazole 1-methylimidazole, 2-dimethylimidazole or Ph₃P). Cyclic voltammetry of the complexes in MeCN shows a reversible one electron reduction wave in the range –1.32 to –1.42 V versus the Ag/AgBF₄ reference electrode.     

Synthesis of new dinuclear dicopper(II) and dinickel(II) complexes. The kinetics of catechol oxidase and electrochemistry of a dicopper(II) complex

A new dinuclear ligand L, ethylene[OO-bis-salicylidene--diketone] bearing two symmetrical coordination sites was synthesized by the condensation of salicylaldehyde and acetylacetone, L, with 1,2-dibromoethane under reflux. The ligand L in a 1:1 ratio was treated with CuCl₂ and NiCl₂ to yield the complexes, tetrachloro bis[OO-bis- salicylidene--diketone copper(II)] and bis[OO-bis-salicylidene--diketone nickel(II)] chloride. The complexes were subsequently characterized by spectroscopic techniques, elemental analysis, i.r., ¹H-n.m.r., ¹³C-n.m.r., u.v.–vis., e.p.r. spectroscopy, and conductance measurements. The conductance measurements in DMF reveal that the Cu^II complex is covalent while the Ni^II complex is ionic and the spectral data support the Cu^II complex to be distorted octahedral whereas the Ni^II complex has square-planar geometry. The dioxygen binding was studied spectrophotometrically by the oxidation of tetrachloro bis[OO-bis-salicylidene--diketone copper(II)] with pyrocatechol in the presence of oxygen. The kinetic experiments were performed with the copper complex in DMF by monitoring the increase in absorbance over time at pH 8.0 in the presence of pyrocatechol at 25 °C. The kinetic parameters V_max and K_M were determined on the Michaelis–Menten Approach. Redox behavior of the dinuclear copper(II) complex was investigated by cyclic voltammetry in the presence of O₂ with the pyrocatechol (substrate) and also without the substrate. The large difference in potentials E⁰ is indicative of reversible oxygen binding of the complex and distinct catalytic activity.     

Stabilities of ternary complexes of cobalt(II), nickel(II), copper(II) and zinc(II) involving aminopolycarboxylic acids and heteroaromaticN-bases as primary ligands and benzohydroxamic acid as a secondary ligand

Summary Stability constants of binary (ML, ML₂) and ternary (MAL) complexes, where M=Co^II, Ni^II, Cu^II or Zn^II; A=iminodiacetic acid (ida), N-methyliminodiacetic acid (mida), anthranilatediacetic acid (ada), nitrilotriacetic acid (nta), 2,2-bipyridine (bipy) andortho-phenanthroline (phen); LH=benzohydroxamic acid, have been determined at 25°C and an ionic strength of 0.1 M KNO₃ by the Irving-Rossotti technique. The results are explained on the basis of astatistical factors; electrostatic effects, steric hindrance, change of electronegativity of the contral metal depending upon the -basic and -acidic character of the primary ligands and also stereochemical factors.     

N2S2 macrocyclic ligands. Synthesis and characterization of novel transition metal complexes of the type [LM(Si2Me6NH)2]2+ and [L′M(Si2Me6NH)2]2+

Summary Novel N₂S₂ macrocyclic ligands, L and L [SS-diethyl(1,3-diaminopropane) dithiocarbamate], [SS-cyclohexyl spiro-(1,3-diaminopropane) dithiocarbamate] and their complexes with Mn^II, Fe^II, Co^II, Ni^II and Cu^II have been characterized by elemental analyses, conductivity measurements, i.r., u.v.-vis. and n.m.r. spectra. The divalent transition metal complexes appear to be square planar and achieve octahedral geometry when treated with bis(trimethylsilyl)-amine to yield new heterobimetallic complexes.     

Palladium(II) and platinum(II) chloride and bromide complexes with some 2-methylpyridyl- or methylquinolyl-benzimidazole,benzoxazole, or benzthiazole

Summary Palladium(II) and platinum(II) complexes [MLX₂], where L=2-(4-methyl-2-pyridyl)benzimidazole (mpbi), 2-(4-methyl-2-pyridyl)benzoxazole (mpbo), 2-(4-methyl-2-quinolyl)benzoxazole (mpbo), 2-(4-methyl-8-quinolyl)benzoxazole (mq'bo), X=Cl. Br, together with M(mqbo)₂Br₂ and Pt₂(mpbt)Cl₄, where mpbt=2-(4-methyl-2-pyridyl)benzthiazole, have been synthesized and characterized by conductivity and magnetic measurements as well as by i.r. and electronic spectra. The ligands are bidentate chelates through the pyridine or quinoline and isoxazole or imidazole nitrogen atoms. The [MLX₂] derivatives arecis, square planar.     

Metal complexes of sulfur-nitrogen chelating agents. Part 12. The chemistry of nickel(II), palladium(II), cobalt(II) and copper(II) complexes of N2S2 and N3S2 donor systems

Summary Nickel(II), palladium(II), cobalt(II) and copper(II) complexes of the ligandN,N-1,2-propane-bis(methyl 2-amino-cyclopent-1-ene-dithiocarboxylate) (H₂L¹),N,N-1,3-propane-bis(methyl 2-aminocyclopent-1-ene-dithiocarboxylate) (H₂L²) andN,N-[bis(methyl 2-aminocyclopent-1-ene-dithiocarboxylate)] diethylenetriamine (H₂L³) have been synthesised. Both H₂L¹ and H₂L² form complexes of the type ML, and all but the copper(II) complexes, are square planar. In the copper(II) complexes tetrahedral distortion is significantly more with CuL². From H₂L³ square planar complexes of the type [M(HL³)X] (M=Ni, X=Cl, Br, I or SCN; M=Pd, X=Cl or Br) have been obtained in which the donor unit involved is N₂SX. The composition of the cobalt(II) and copper(II) complexes is [M(H₂L³)X₂] (X=Cl or Br) which contain the chromophore [MN₃X₂].     

Complexes of 2-(2-hydroxyacetophenone)imino-5-(p-anisyl)-1,3,4-oxadiazole with some bivalent metals ions

Summary The metal complexes of the type [M(SB)₂(H₂O)₂] and [M(SB)₂][where M = Mn^II, Co^II, Ni^II or Cu^II, M = Zn^II Cd^II, Hg^II and Pb^II and SBH = 2-(2-hydroxyacetophenone)imino-5-(p-anisyl)-1,3,4-oxadiazole] have been prepared and characterised by elemental analyses, thermal analyses, magnetic measurements, electronic and infrared spectral studies. The complexes [M(SB)₂(H₂O)₂] possess octahedral structures, whereas complexes [M(SB)₂] are tetrahedral. The crystal field parameters of the Co^II and Ni^II complexes are also calculated.     

Binuclear and mononuclear cobalt(II), nickel(II) and copper(II) complexes of 4,4′-bis(alkylaminoisonitrosoacetyl)diphenyl-methane derivatives

4,4-Bis(chloroacetyl)diphenylmethane has been prepared from ClCH₂COCl and Ph₂CH₂. 4,4-Methylenebis(phenylglyoxylohydroximoyl chloride has also been obtained. Four new substituted 4,4-bis(alkylaminoisonitrosoacetyl)diphenylmethanes (ligands) have been prepared from 4,4-methylenebis(phenylglyoxylohydroximoyl chloride) and the corresponding amines. The Ni^II, Cu^II and Co^II complexes of these ligands were prepared and their structures were identified using AAS, i.r., ¹H-n.m.r. spectral data, elemental analyses and magnetic susceptibility measurements.     

O-phenylenebis(oxamato) bridged trinuclear copper(II) complexes: synthesis and magnetic properties

Summary Four new trinuclear copper(II) complexes bridged by o-phenylenebis(oxamato) (opba) and end-capped with 1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (NO₂-phen), 2,2-bipyridyl (bipy) or 4,4-dimethyl-2,2-bipyridyl (Me₂bipy), {[Cu(opba)][Cu(L)]₂}(ClO₄)₂ (L = phen, NO₂-phen, bipy or Me₂bipy), have been synthesized and characterized. Based on i.r., elemental analyses, conductivity measurements and electronic spectra, oxamato-bridged structures consisting of three copper(II) ions in which each copper(II) ion has a square-planar environment are proposed. The temperature-dependent magnetic susceptibility of {[Cu(opba)][Cu(phen)]₂} (ClO₄)₂ has been studied in the 4.2–300 K range, giving the exchange integral J = -134.4cm^–1. The result revealed the operation of an antiferromagnetic spin-exchange interaction between the adjacent copper ions.     

Size and stability of chelate rings in coordination compounds of cobalt(II), manganese(II), iron(III) and palladium(II) with vicinal oxime-imine ligands

Summary Two types of the Co^II complexes L¹Co (H₂L¹=N,N-ethylenebis(isonitrosoacetylacetoneimine) were prepared. In type (a) the chelate rings are five-membered whereas in type (b) they are six-membered. The type (b) complexes were converted to type (a) in refluxing solutions. Half-ionization of the ligand is observed in the complexes HL¹ Co(O₂CMe) and HL¹MnCl, where the chelate rings are five- and six-membered respectively. The octahedral complex L¹FeCl·H₂O has chelate rings of type (a) as does the complex L²Co (H₂L²=unsymmetric Schiff baseN,N-ethylene(isonitrosoacetylacetoneimineacetylacetoneimine). Twocis complexes (L_a ²L_b ³)Pd and (L_a ³)₂Pd are characterized (HL³=isonitrosoacetylacetoneimine, (a) and (b) denote the type of chelate ring). Structures for the metal complexes and the sizes of the chelate rings are suggested on the basis of analytical and spectral evidence.     

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.     

Antibacterial activity of ruthenium(II) carbonyl complexes containing tetradentate Schiff bases

Several new hexa-coordinated ruthenium(II) complexes of the type [Ru(CO)(LL)(B)] (where, LL = anthacac, anthdibm, 2-amtpacac or 2-amtpdibm; B = PPh₃ or py or pip or morph) have been prepared by reacting [RuHCl(CO)(PPh₃)₃] or [RuHCl(CO)(PPh₃)₂(B)] with tetradentate Schiff bases such as bis(anthranilic acid)acetylacetimine (H₂-anthacac), bis(anthranilic acid) dibenzoylmethimine (H₂-anthdibm), bis(2-aminothiophenol) acetylacetimine (H₂-2-amptacac) or bis(2-aminothiophenol) dibenzoylmethimine (H₂-2-amtpdibm). The complexes have been characterised by elemental analyses and spectral (i.r., electronic spectra, ¹H- and ³¹P-n.m.r.) data. An octahedral structure has been tentatively proposed for the complexes, which were also tested for their antibacterial properties.