Showing papers in "Synthesis and Reactivity in Inorganic and Metal-organic Chemistry in 2001"

Synthesis, characterization, and biological activities of ruthenium(ii) carbonyl complexes containing bifunctional tridentate schiff bases

Abstract: Ruthenium(II) carbonyl complexes have been synthesised by reacting [RuH2(CO)(PPh3)3] or [RuHCl(CO)(PPh3)2(Z)] (Z = PPh3, pyridine (py) or piperidine (pip)) with tridentate Schiff base ligands derived by condensing salicylaldehyde, o-vanillin or o-hydroxyacetophenone with N(4)-phenylsemicarbazide. These complexes have been characterised by analytical, IR, electronic, 1H NMR and 31P NMR spectral studies. The complexes of the general formula [Ru(L)(CO)(PPh3)(Z)] (L = Schiff base anion; Z = PPh3, py or pip) tentatively have been assigned an octahedral structure. Some of the complexes have been tested for in vitro growth inhibitory activity against the bacteria Escherichia coli, Bacillus sp. and Pseudomonas sp.

Synthesis, spectroscopic characterization, redox, and biological screening studies of some schiff base transition metal(ii) complexes derived from salicylidene-4-aminoantipyrine and 2-aminophenol/ 2-aminothiophenol

Abstract: Neutral complexes of Cu(II), Ni(II), Co(II), Mn(II), VO(IV) and Zn(II) have been synthesised from the Schiff bases derived from salicylidene-4-aminoantipyrine and 2-aminophenol/2-aminothiophenol. The structural features have been arrived at from their microanalytical, IR, UV-Vis., 1H NMR and ESR spectral data. All of the complexes exhibit square-planar geometry except the Mn(II) and VO(IV) complexes. The Mn(II) chelates show an octahedral environment and the VO(IV) chelates exist in a square-pyramidal geometry. The non-electrolytic and monomeric nature of the complexes are evidenced by their magnetic susceptibility and low conductance data. The electrochemical behaviour of the Cu(II), Mn(II) and VO(IV) complexes in DMSO at 300 °K were studied. [CuL1] complex shows an irreversible peak for the copper(II)/copper(I) couple at Epc1 = 0.16 V and Epa = 0.53V referenced to Ag/AgCl. The cyclic voltammogram of the [CuL2] complex in MeCN at 300°K shows a quasi-reversible peak for the couples copper(II)/copper(III) ...

NOVEL COMPLEXES OF MANGANESE(III), COBALT(II), COPPER(II), AND ZINC(II) WITH SCHIFF BASE DERIVED FROM 1,2-BIS(p-AMINO-PHENOXY)ETHANE AND SALICYLALDEHYDE

Abstract: Several new complexes of the Schiff base obtained by the condensation of 1,2-bis(p-aminophenoxy)ethane with salicylaldehyde were synthesized. The complexes have been characterized by elemental analyses, magnetic measurements, 1H NMR, UV-VIS and IR spectra. The ligand is coordinated to the central metal as a tetradentade ONNO ligand. The four bonding sites are the azomethine nitrogen and the o-OH groups.

SYNTHESIS, SPECTRAL AND BIOLOGICAL STUDIES OF Mn(II), Ni(II), Cu(II), AND Zn(II) COMPLEXES WITH A TETRADENTATE SCHIFF BASE LIGAND. COMPLEXATION STUDIES AND THE DETERMINATION OF STABILITY CONSTANTS (Ke)

Abstract: The complexes Mn(II), Ni(II), Cu(II) and Zn(II) ions with a N2O2 Schiff base derived from 1,4-diaminobutane and salicylaldehyde, N,N′-bis(salicylidene)-1,4-diaminobutane (LH2), have been prepared and characterized by elemental analyses, molar conductivities, spectral (IR, NMR, visible, UV) and magnetic moment measurements. Stability constants were measured by means of a conductometric method. Furthermore, the stability constants for complexation between ZnCl2, Cu(NO3)2 and AgNO3 salts and the ligand in 80% dioxane-water and pure methanol were determined by conductance measurements. The magnitudes of these ion association constants are related to the nature of the solvation of the cation and the complexed cation. The mobilities of the complexes are also dependent, in part, upon solvation effects. The complexes Mn(II), Ni(II), Cu(II) and Zn(II) ions with the Schiff base have been evaluated for their antibacterial activity against rec − and rec + stains of Bacillus subtilis.

Copper(ii), cobalt(iii), nickel(ii), palladium(ii), and zinc(ii) complexes of the schiff base ligands derived from 2,6-diacetylpyridine and phthaldialdehyde

Abstract: Two new ligands, N,N′-bis[2-hydroxy-3-methoxy-N-(pyridyl) benzylamine]-2,6-di acetylidenepyridine (H2L′) and N, N′-bis [2-hydroxy-3-methoxy-N-(pyridyl)benzylamine]-1,2-phthaldialdimine (H2L″) and their Cu(II), Co(III), Ni(II), Pd(II) and Zn(II) complexes have been prepared and characterized by elemental analyses, IR, electronic spectra, magnetic moments, 1H and 13C NMR spectra, mass spectral and molar conductance data. The mononuclear Co(III) complexes of these ligands have been isolated with two molecules of DMF. While the Co(III) complex of H2L′ is a 1:1 electrolyte, the other complexes and ligands are non-electrolytes. The ligands H2L′ and H2L″ and some of their complexes show antimicrobial activity against bacteria and yeast.

Cobalt(II) complexes of 1,2-(diimino-4′-antipyrinyl)ethane and 4-N-(4′-antipyrylmethylidene)aminoantipyrine

Abstract: Cobalt(II) complexes of the Schiff bases 1,2-(diimino-4′-antipyrinyl)ethane (GA) and 4-N-(4′-antipyrylmethylidene)aminoantipyrine (AA) have been prepared and characterised by elemental analysis, electrical conductance in non-aqueous solvents, i.r. and electronic spectra, as well as by magnetic susceptibility measurements. The complexes have the general formulae [Co(GA)X]X (X = ClO−4 or NO3−), [Co(GA)X2] (X = Cl−, Br− or I−), [Co(AA)2]X2 (X = ClO4−, NO3−, Br− or I−) and [Co(AA)Cl2]. GA acts as a neutral tetradentate ligand, coordinating through both carbonyl oxygens and both azomethine nitrogens. In the perchlorate and nitrate complexes of GA one anion is coordinated in a bidentate fashion, whereas in the halide complexes both anions are coordinated to the metal, generating an octahedral geometry around the Co ion. AA acts as a neutral bidentate ligand, coordinating through the carbonyl oxygen derived from the aldehydic moiety and the azomethine nitrogen. Both anions remain ionic in the perchlorate, nitrate, bromide and iodide complexes of AA, whereas both anions are coordinated to the metal ion in the chloride complex, resulting tetrahedral geometry around the Co ion.

Preparation, chemical characterization, and electronic spectra of 6-(2-pyridylazo)-3-acetamidophenol and its metal complexes

Abstract: The stereochemistry of new iron(III), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes of 6-(2-pyridylazo)-3-acetamidophenol (H2L) is studied on the basis of their analytical, spectroscopic, magnetic, thermal and conductance data. The dissociation constant of the ligand as well as the stability constants of its metal complexes have been determined spectrophotometrically. On the basis of the infrared spectra the coordination behaviour of the ligand to the metal ions is investigated. Magnetic susceptibility and solid reflectance spectral measurements are used to infer the structure. The prepared complexes are found to have the general formulae [M(HL)(H2O)x](A) · yH2O (M = Cu(II), Zn(II), Cd(II) and Fe(III); HL = 6-(2-pyridylazo)-3-acetamidophenolate; A = acetate in case of Cu(II) and Zn(II) or chloride in case of Cd(II) and Fe(III), x = 1–3 and y = 0–5) or [M(H2L)(H2O) x ]Cl2 · yH2O (M = Ni(II) and Co(II); H2L = 6-(2-pyridylazo)-3-acetamidophenol, x = 3 and y = 5–6).

Synthesis and characterization of manganese(iii) complexes of schiff bases derived from amino acids and 2-hydroxy-1-naphthaldehyde

Abstract: New complexes of Mn(III) with Schiff bases obtained by the condensation of 2-hydroxy-1-naphthaldehyde with glycine, L-alanine, L-phenylalanine, L-histidine, L-tryptophan and L-threonine have been synthesized and characterized by elemental analyses, UV, IR, magnetic susceptibility, thermogravimetry and non-aqueous titration. These complexes are coordinated through the ONO donor set derived from the carboxyl, imino and phenoxy groups of the ligands. Furthermore, the Schiff bases were obtained as solids and their structures were determined by IR, UV, 1H NMR to compare with those of the complexes.

SYNTHESIS AND CHARACTERIZATION OF SOME 3-PHENYL-4-ARYLAZO-5-PYRAZOLONES WITH La(III), Ce(III), Th(IV), AND UO2(VI) COMPLEXES

Abstract: La(III), Ce(III), Th(IV) and UO2(VI) chelates with 3-phenyl-4-arylazo-5-pyrazolones have been synthesized and were characterized by several analytical tools such as elemental analyses, IR, NMR, TG and molar conductance techniques. The data obtained show that all of the prepared complexes contain water and/or alcohol molecules in their coordination sphere and the ligands form 1:1 and 1:2 complexes which are in good agreement with the proposed formulae. The NMR data of the prepared ligands show the existence of the ketonic structure rather than the enolic form. The TG data revealed no crystal water outside the coordination sphere. The azopyrazolone ligands act as neutral bidentate ligands bonded to the metal ions through the oxygen atom of the carbonyl group and the α nitrogen of the arylazo group. All solid chelates prepared behave as non-electrolytes in DMF solution. The coordination numbers of the prepared chelates are ranging from 6 to 12 for 1:1 and from 7 to 12 for 1:2 chelates.

Synthesis and spectral studies of transition metal complexes with 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,7,11,14-tetraene, a fourteen-membered tetradentate macrocyclic ligand

Abstract: Complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Pd(II) and Cu(II) with a fourteen-membered macrocyclic ligand have been prepared and characterized by magnetic moment, infrared, electronic and EPR spectral studies. All of complexes were found to have six-coordinate geometry and are of the high-spin type except the Pd(II) complex which is four-coordinate, square-planar and diamagnetic.

Synthesis and characterization of new ruthenium(iii) complexes containing tetradentate schiff bases

Abstract: Several new hexa-coordinated ruthenium(III) complexes of the type [RuX(EPh3)(LL′)] (X=Cl, Br; E=P, As; LL′ = anthacac, anthdibm, 2-amtpacac or 2-amtpdibm) have been synthesised by reacting [RuCl3(PPh3)3], [RuCl3(AsPh3)3], [RuBr3(AsPh3)3] or [RuBr3(PPh3)2(MeOH)] 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). All of the complexes have been characterised by elemental analyses, IR, electronic spectra, EPR, magnetic moment and cyclic voltammetric data. An octahedral structure has been tentatively proposed for the complexes. These complexes were also tested for their antibacterial properties.

SYNTHESIS, CHARACTERIZATION, AND BIOLOGICAL PROPERTIES OF BIVALENT TRANSITION METAL COMPLEXES OF Co(II), Cu(II), Ni(II), AND Zn(II) WITH SOME ACYLHYDRAZINE DERIVED FURANYL AND THIENYL ONO AND SNO DONOR SCHIFF BASE LIGANDS

Abstract: Some acylhydrazine derived furanyl and thienyl ONO and SNO donor Schiff base ligands and their Co(II), Cu(II), Ni(II), and Zn(II) complexes have been prepared and characterized on the basis of elemental analyses, magnetic moments, molar conductances, and spectroscopic (electronic, IR, 1H NMR, and 13C NMR) data. All of the ligands function as tridentates and the deprotonated enolic form is preferred in the coordination.

Synthesis, characterization, and antimicrobial activities of some transition metal complexes with a tridentate dibasic schiff base and bidentate 2,2′-bipyridylamine

Abstract: The mixed-ligand complexes of Cu(II), Ni(II), Zn(II), Co(II), Fe(II), Mn(II), and Cd(II) with 2,2′-bipyridylamine (Bipy-amine) and a Schiff base (H2SB) were prepared and characterized on the basis of elemental analyses, magnetic measurements, infrared spectra, electronic spectra and thermogravimetric analyses. An octahedral geometry has been assigned to all of the prepared complexes. The antimicrobial activities of the complexes were tested against bacteria, yeast and fungi and the results are discussed.

Investigations on some hetero-trinuclear complexes of nickel(ii) and copper(ii)

Abstract: Ni(II) and Cu(II) complexes of N,N′-bis(salicylidene-1,3-diaminopropane) were prepared and found to form linear and non-linear trinuclear complexes. Elemental analyses, IR spectroscopy, thermogravimetry and X-ray diffraction techniques applied to the complexes yielded valuable information about their moleculer structures. It was observed that μ-bridges in these trinuclear complexes form through the phenolic oxygens of the ligand or through anions present in the medium. In the presence of acetate, nitrate or nitrite, μ-bridges form between a pair of atoms resulting in linear trinuclear complexes. However, the presence of chloride or bromide results in μ-bridges involving the phenolic oxygens of N,N′-Bis(salicylidene)-1,3-diaminopropane.

PHOTOCHEMICAL SYNTHESIS OF METAL CARBONYL COMPLEXES OF TETRAALKYLDIPHOSPHINE DISULFIDES, [M2(CO)10(μ-R2P(S)P(S)R2)] (M = Mo, W; R = Me, Et, n-Pr, n-Bu)

Abstract: The new complexes [M2(CO)10(μ-R2P(S)P(S)R2)] (M = Mo, W; R = Me, Et, n-Pr, n-Bu), (la)–(1d) and (2a)–(2d) [(1a), M = Mo, R = Me; (1b), M = Mo, R = Et; (1c), M = Mo, R = n-Pr; (1d), M = Mo, R = n-Bu; (2a), M = W, R = Me; (2b), M = W, R = Et; (2c), M = W, R = n-Pr; (2d), M = W, R = n-Bu] have been prepared by the photochemical reaction of M(CO)6 with R2P(S)P(S)R2 (R = Me, Et, n-Pr, n-Bu). The complexes have been characterized by elemental analyses, FT-IR and 31P-[1H]-NMR spectroscopy and FAB-mass spectrometry. The spectroscopic studies suggest cis-bridging bidentate coordination of the ligand between the two metals.

SYNTHESIS OF MONO AND BINUCLEAR COMPLEXES OF α-OXIMINOACETOACETANILIDE-4-PHENYLTHIOSEMICARBAZONE

Abstract: Transition metal complexes of α-oximinoacetoacetanilide-4-phenylthiosemicarbazone (H3AT) have been synthesized. Attempts were made to elucidate their geometries by elemental and thermal analyses, molar conductance, magnetic measurements and spectroscopy (IR and electronic). All the investigated metal ions form mononuclear complexes except the Cu(II) and Fe(III) ions which form binuclear complexes. The ligand behaves as a binegative tridentate species and coordinates via the thiol sulfur and azomethine nitrogens of the oxime and thiosemicarbazone moieties with Cu(II), Ni(II) and Pd(II) ions, and as a trinegative tridentate species with Fe(III) ion forming a sulfur bridge. The loss of thiol and oxime hydrogens is confirmed by the pH titrations of H3AT and its metal(II) complexes against 0.01 M NaOH. The protonation constants (log K1 H=10.7 and log K1 H = 6.6) were calculated as well as the stability constants of the metal complexes. The ligand may be applied as analytical reagent for the spectrophotometric ...

Synthesis and characterization of copper ascorbate

Abstract: The preparation of copper ascorbate in CH2Cl2 is described. The reaction between copper(II) methoxide and L-ascorbic acid in the presence of N,N,N′,N′-tetramethylethylenediamine (TMEDA) and under strictly anaerobic conditions leads to the formation of a stable Cu(II)-ascorbate complex. No redox reaction takes place. Spectroscopic evidence suggest that the compound is polymeric where Cu(II) is chelated by the enolic oxygens of one ascorbate unit and the side chain alcoholic oxygens of another.

COMPLEXATION REACTIONS OF Dy(III), Er(III), Gd(III), Ho(III), AND Sm(III) IONS WITH THENOYLTRIFLUOROACETONE

Abstract: The reactions of thenoyltrifluoroacetone (HTTF) and LnCl3 (Ln = Dy(III), Er(III), Gd(III), Ho(III) and Sm(III)) in 3:1 ligand:metal molar ratio have been investigated. The isolated solid products have been characterized by spectroscopy (UV-Vis, IR and 1H NMR), thermogravimetry and elemental analyses. The microanalytical data of the investigated compounds are consistent with the chemical formulas Ln(TTF)3(H2O)2 (Ln = Dy, Gd and Ho), Er(TTF)3, and Sm(TTF)2Cl(H2O). The charge densities on the ligand atoms were calculated by CNDO-SCF calculations. The antibacterial activities of the investigated complexes were tested and evaluated.

Metal complexes of novel symmetrical schiff base ligands

Abstract: Two novel symmetrical Schiff base ligands, H2L1 and H2L2, with tetradentate N2O2 and pentadentate N3O2 coordinating sites were prepared by the reaction of the aldehyde 2-methyl-7-formyl-8-hydroxy-quinoline with 1,3-diaminopropane or diethylenetriamine, respectively, in the molar ratio 2:1. Cu(II), Ni(II), Co(II), Mn(II), Fe(III) and VO(IV) complexes of both ligands were synthesized. The ligands and their metal complexes were characterized by elemental analyses, IR, UV-Vis, ESR, NMR and mass spectra and also by magnetic moment measurements. Both ligands behave as tetradentate ones when coordinating metal cations. The ligand H2L1 has a smaller cavity than the ligand H2L2, thus the former ligand yielded mononuclear products, through chelation of one ligand molecule to a metal cation, while the latter ligand yielded binuclear products, through the coordination of two metal cations to two ligand molecules. Each of the Fe(III) cations was coordinated to three halves of both ligand molecules yielding also a mono...

Template synthesis and x-ray structure determination of unsymmetrical tetradentate schiff base complexes of nickel(ii) and copper(ii)

Abstract: Nickel(II) and copper(II) complexes of unsymmetrical tetradentate Schiff bases have been synthesized by the template reaction of the half-units N-(1-hydroxy-2-acetonaphthone)-1-amino-2-phenyleneimine) (HL) and N-(2-hydroxyacetophenone)-1-amino-2-phenyleneimine (HL1) with glyoxal monophenylhydrazone (HL2). The ligands (L-L2) and (L1-L2) formed are in situ, respectively. The complexes have been characterized by molar conductance, IR, 1H NMR and UV spectroscopy. The crystal structure of the Ni(II) complexes have been determined by X-ray crystallography and exhibit square-planar conformation. Crystals of Ni(L1-L2) are monoclinic, space group P21, with a = 10.2552(5), b = 7.3422(4), c = 12.2414(6) A, β = 93.0910(10)°, Z = 2. Crystals of Ni(L-L2) are monoclinic, space group C2/c, with a = 24.5353(4), b = 9.8615(3), c = 22.2809(5) A, β = 122.7710(10)°, Z = 8. The Ni-O and Ni-N bonds have very similar lengths and form a regular square-planar structure.

SYNTHESIS, CHARACTERIZATION, LIGATIONAL AND BIOLOGICAL PROPERTIES OF SOME ACYLHYDRAZINE DERIVED FURANYL AND THIENYL SCHIFF BASES WITH Co(II), Cu(II), Ni(II), AND Zn(II) METAL IONS

Abstract: Some acylhydrazine-derived furanyl and thienyl Schiff bases and their Co(II), Cu(II), Ni(II) and Zn(II) complexes have been prepared and characterized on the basis of their elemental analyses, magnetic moments, molar conductances and spectroscopic (electronic, IR, 1H NMR and 13C NMR) data. All of the Schiff base ligands function as tetradentates forming octahedral complexes with Co(II), Ni(II) and Zn(II) ions and a square-planar complex with Cu(II) ion. The ketonic form for the ligands L1 and L2 are the enolic form for the ligands L3 and L4 are preferred in the coordination. All of the ligands are biologically active and, in comparison, their metal complexes have shown higher bactericidal activity against one or more bacterial species such as Escherichia coil, Staphylococcus aureus, or Pseudomonas aeruginosa.

SYNTHESIS AND CHARACTERIZATION OF SOME ORGANOTIN(IV) COMPLEXES OF α-BENZOIN OXIME

Abstract: Some di- and triorganotin(IV) complexes of α-benzoin oxime of the general formulae R3SnL, R2SnCl2−n L n , and R2SnL have been synthesized by the reactions of the corresponding di- and triorganotin(IV) chlorides with the sodium salt of α-benzoin oxime in the desired molar ratios. All of the compounds have been characterized by elemental analyses and spectral (IR,1H, 13C, and 119Sn NMR) studies.

TEMPLATE SYNTHESIS OF TWO NEW GLYOXIME DERIVATIVES. CHARACTERIZATION AND INVESTIGATION OF THEIR COMPLEXES WITH Ni(II), Cu(II), AND Co(II) METAL IONS

Abstract: Two novel oximes containing di- and tetraoxime groups, dichloro-[N,N′-bis(2-aminophenyl)diaminoglyoxime]nickel(II), [Ni(LH2)Cl2], and {dichloro-[5,6:11,12-dibenzo-2,3,8,9-tetra-(hydroxyimino)-1,4,7,10-tetraazacyclododecane]}- nickel(II), [Ni(LH4)Cl2], have been synthesized by the template condensation reaction of dichloro-[N,N′-bis-(1,2-diaminobenzene)]nickel(II) with anti-dichloroglyoxime. Trinuclear complexes of [Ni(LH2)Cl2] with Ni(II), Cu(II) and Co(II) have been synthesized. A polynuclear complex of [Ni(LH4)Cl2] with Ni(II) has been prepared. The structures of these novel oxime compounds are proposed on the basis of the elemental analyses, IR and UV-Visible spectra and conductivity measurements. Conductivity measurements have shown that all complexes are non-electrolytes.

Mechanistic investigations of the oxidation of substituted phenethyl alcohols by manganese(iii) sulfate catalyzed by ruthenium(iii) in acid solution

Abstract: The kinetics of the Ru(III) catalysed oxidation of six derivatives of phenethyl alcohol (X-C6H4-CH2CH2OH where X═H, Cl, Br, CH3, OCH3 or NO2) by manganese(III) sulfate, in sulfuric acid solution at 30°C, were followed spectrophotometrically at λmax =500 nm. The rate shows a first-order dependence on [Mn(III)] and Michaelis-Menten kinetics was observed with the substrate. The rate was of fractional-order in [Ru(III)]. Hammett acidity function (─H0) has been invoked to explain the retardation of the rate by acid. Bunnett plots indicated the absence of water molecule participation in the rate-limiting step. Variation of the ionic strength and the dielectric constant and the addition of the reaction product Mn(II) and anions such as C1−, SO2+ 4, and F− have no effect on the rate. The solvent isotope effect k(H2O)/k(D2O) =1.38 was observed. Proton inventory studies were made in H2O-D2O mixtures. A linear free energy relationship was observed when the results were analyzed by Hammett and Okamoto-Brown equations...

Synthesis, electronic, and magnetic properties of some 3-substituted 2,4-pentanedionatooxovanadium(iv) complexes and their 4-methylpyridine adducts

Abstract: Oxovanadium(IV) complexes of various 3-substituted 2,4-pentanediones [VO(H3CCOCHRCOCH3]2 where R = CH3, C2H5, i-C3H7, n-C4H9, i-C4H9, C6H5, CH3CO, C6H5CH2, have been synthesized and their adducts with 4-methylpyridine prepared. The compounds were characterized by elemental analyses, magnetic susceptibility, infrared and electronic spectral measurements. The infrared vanadyl stretching frequency ν(V = O) were observed in the range 940–998 cm−1 indicating the non-existence of polymeric structures. The infrared and electronic spectral studies indicate that the oxovanadium(IV) β-diketone complexes assume a square-pyramidal geometry while the adducts adopt a six-coordinate octahedral geometry. The effective magnetic moments (μeff) for the complexes at room temperature are between 1.71 and 1.76 B.M. indicating the compounds are magnetically dilute. Possible structures for the compounds are suggested.

Synthesis and properties of octakis(octylthio)- porphyrazinatoiron derivatives

Abstract: Chlorooctakis(octylthio)porphyrazinatoiron(III) (FePzCl) was prepared by the reaction of metal-free porphyrazine with iron(II) acetate and further treatment with HCl solution. The monomeric bisaxial complex FePz(py)2 as well as the bridged complex [FePz(pyz)]n were formed as stable complexes by reacting FePzCl with pyridine or pyrazine, respectively. These complexes were characterized by elemental analysis and spectroscopic methods.

METAL COMPLEXES OF TRIAZINE SCHIFF BASES: SYNTHETIC, THERMODYNAMIC, SPECTROSCOPIC, AND ELECTROCHEMICAL STUDIES ON COMPLEXES OF SOME DIVALENT AND TRIVALENT METAL IONS OF 3-(α-BENZOYLBENZYLIDENHYDRAZINO)-5,6-DIPHENYL-1,2,4-TRIAZINE

Abstract: Metal complexes of some divalent and trivalent metal ions, viz. Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pr(III), Nd(III), Sm(III) and Yb(III) with a Schiff base 3-(α-benzoylbenzylidene-hydrazino)- 5,6-diphenyl-1,2,4-triazine (HBZDT) have been investigated potentiometrically, spectrophotometrically and electrochemically and found to have the metal : ligand ratios 1 : 1 and 1 : 2. The dissociation constant of the ligand and the formation constants of the metal-ligand complexes have been determined potentiometrically at different temperatures and 0.1 M ionic strength (KNO3) in 75% (v/v) dioxan-water solution. The standard thermodynamic parameters, viz. Δ G°, ΔH°, and ΔS°, terms for dissociation and the stepwise formation of the metal-ligand complexes have been evaluated. The thermodynamic functions have been analyzed in terms of the electrostatic (el) and non-electrostatic (non) components. ΔH° non was found to be linearly correlated with the acceptor number of the metal ion (ANM), whereas ΔH° el was correla...

Coordination chain polymers of some transition metals with schiff base

Abstract: The Schiff base derived from terephthalaldehyde and o-aminophenol is known as N,N′-di(o-hydroxyphenyl)terephthalaldehydediimine and is termed here as H2SB The polychelates of this Schiff base having the general formula [M(SB)(H2O)2]n [where M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)] have been synthesized and characterized on the basis of elemental analyses, infrared spectra, electronic spectra, magnetic measurements and thermogravimetric analyses The Schiff base act as uninegative bidentate ligand and bonding occurs through the hydroxyl oxygen and nitrogen atoms An octahedral geometry has been assigned to all of the prepared polychelates

Synthesis and esr studies of a soluble vanadyl porphyrazine

Abstract: Octakis(hexylthio)vanadyl porphyrazinate, (VOPz), was prepared from vanadyl(IV) sulfate and metal-free porphyrazine (H2Pz), which was synthesized by the cyclotetramerization of the corresponding dinitrile derivative and further treatment with trifluoroacetic acid. Intense absorption peaks at 699 and 352 nm in the electronic spectrum indicated the C4v symmetry of VOPz. ESR studies, both in solution and in powder form, confirmed the proposed structure.

Synthesis, esr, magnetic, and electronic spectral studies on manganese(ii) complexes of semicarbazone and thiosemicarbazone

Abstract: Manganese(II) complexes of the general composition Mn(L)2-X2 (where L = p-methyl acetophenone semicarbazone (HL1) and thiosemicarbazone (HL2) and X = Cl, Br, (1/2 SO4) have been synthesized. All of the complexes were characterized by elemental analyses, magnetic moments, electronic and ESR spectral studies. The complexes were found to have magnetic moments corresponding to five unpaired electrons. Possible geometries of the complexes were assigned on the basis of electronic and ESR spectra.