Spectroscopic characterization and biological activity of metal complexes with an ONO trifunctionalized hydrazone ligand

A series of Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), La(III), Ru(III), Hf(IV), Zr(IV) and U(VI) complexes of phenylamino acetoacetylacetone hydrazone have been synthesized and characterized by elemental analyses, IR, UV–Vis, magnetic moments, conductances, thermal analyses (DTA and TGA) and ESR measurements. The IR data show that the ligand is neutral bidentate, monobasic bidentate, monobasic tridentate or dibasic tridentate towards the metal ion. Molar conductances in DMF indicate that the complexes are non-electrolytes. The ESR spectra of solid [(L)(HL)Cu₂(NO₃)(H₂O)]·1/2H₂O (10) and [(H₂L)Cu(Cl)₂(H₂O)₂] (11) show axial spectra with g_∥ >?g_⊥ >?2.0023 indicating d_(x²???y²) ground state with significant covalent bond character. However, [(HL)₂Mn₂(Cl)₂(H₂O)₄·H₂O (13) shows an isotropic spectrum, indicating manganese(II) to be octahedral. Antibacterial and antifungal tests of the ligand and some of its metal complexes revealed that the complexes are more potent bactericides and fungicides than the ligand.     

Synthesis,Characterization and Antifungal Activity of Metal Complexes of 2-(5-((2-Chlorophenyl)Diazenyl)-2-Hydroxybenzylidene) Hydrazinecarbothioamide

Abstract

New metal complexes of Co(II), Cu(II), Ni(II), Zn(II), Mn(II), Fe(III), Ru(III), UO₂(II), and VO(II) with the Schiff base, 2-(5-((2-chlorophenyl)diazenyl)-2-hydroxy- benzylidene) hydrazine-carbothioamide (H₂L) have been prepared and characterized by elemental and thermal analyses, FT-IR, UV–Vis, mass spectra, ¹H-NMR, and ESR as well as conductivity and magnetic moments measurements. The IR spectra showed that the ligand acts as neutral tridentate, neutral bidentate or monobasic tridentate ligand. The geometries of metal complexes were either octahedral or square pyramidal. The ESR spectra of the solid copper(II) complexes indicated an axial symmetry type of a d_(x2-y2) ground state with considerably ionic or covalent environment. The effect of the presence of an azo group on the biological activity of the ligand was investigated. The ligand and its complexes are biologically inactive due to the presence of azo group.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the related elements to view the free supplemental file.     

Synthesis,characterization, and biological activity of metal complexes of azohydrazone ligand

A new azohydrazone, 2-hydroxy-N′-2-hydroxy-5-(phenyldiazenyl)benzohydrazide (H₃L) and its copper(II), nickel(II), cobalt(II), manganese(II), zinc(II), cadmium(II), mercury(II), vanadyl(II), uranyl(II), iron(III), and ruthenium(III) complexes have been prepared and characterized by elemental and thermal analyses as well as spectroscopic techniques (¹H-NMR, IR, UV-Vis, ESR), magnetic, and conductivity measurements. Spectral data showed a neutral bidentate, monobasic bidentate, monobasic tridentate, and dibasic tridentate bonding to metal ions via the carbonyl oxygen in ketonic or enolic form, azomethine nitrogen, and/or deprotonated phenolic hydroxyl oxygen. ESR spectra of solid vanadyl(II) complex (2), copper(II) complexes (3–5), and (7) and manganese(II) complex (10) at room temperature show isotropic spectra, while copper(II) complex (6) shows axial symmetry with covalent character. Biological results show that the ligand is biologically inactive but the complexes exhibit mild effect on Gram positive bacteria (Bacillus subtilis), some octahedral complexes exhibit moderate effect on Gram negative bacteria (Escherichia coli), and VO(II), Cd(II), UO(II), and Hg(II) complexes show higher effect on Fungus (Aspergillus niger). When compared to previous results, metal complexes of this hydrazone have a mild effect on microorganisms due to the presence of the azo group.     

Synthesis,structural, spectroscopic,and thermal studies of some transition-metal complexes of a ligand containing the amino mercapto triazole moiety

A new series of transition-metal complexes of Schiff base ligand containing the amino mercapto triazole moiety ( HL ) was prepared. The Schiff base and its metal complexes were elucidated by different spectroscopic techniques (infrared [IR], ¹H nuclear magnetic resonance, UV–Visible, mass, and electron spin resonance [ESR]), and magnetic moment and thermal studies. Quantum chemical calculations have been carried out to study the structure of the ligand and some of its complexes. The IR spectra showed that the ligand is chelated with the metal ion in a neutral, tridentate, and bidentate manner using NOS and NO donors in complexes 1 – 6 , 10–12 , and 7 and 8 , respectively, whereas it behaves in a monobasic tridentate fashion using NOS donor sites in copper(II) nitrate complex ( 9 ). The magnetic moment and electronic spectra data revealed octahedral and square pyramidal geometries for complexes 2 , 11 , 12 , and 5 – 8 and 10 , respectively. However, the other complexes were found to have tetrahedral ( 4 ), trigonal bipyramidal ( 1 and 3 ), and square planar ( 9 ) structures. Thermal studies revealed that the chelates with different crystallized solvents undergo different types of interactions and the decomposition pathway ended with the formation of metal oxygen (MO) and metal sulfur (MS) as final products. The ESR spectrum of copper(II) complex 10 is axial in nature with hyperfine splitting with ²B_1g as a ground state. By contrast, complexes 7 and 8 undergo distortion around the Cu(II) center, affording rhombic ESR spectra. The HL ligand and some of its complexes were screened against two bacterial species. Data showed that complex 12 demonstrated a better antibacterial activity than HL ligand and other chelates.     

Synthesis,spectroscopic investigation and biological activity of metal complexes with ONO trifunctionalalized hydrazone ligand

Mn^II, Fe^III, Co^II, Ni^II, Cu^II, Zn^II, La^III, Ru^III, Hf^IV, Zr^IV and U^VI complexes of 4-methylphenylamino acetoacetylacetone hydrazone have been synthesized and characterized by elementals analyses, i.r., u.v.–vis. spectra, magnetic moments, conductances, thermal analyses (d.t.a and t.g.a) and e.s.r measurements. The i.r. data show that, the ligand behaves as a neutral bidentate type (10), (13) and neutral tridentate type (4), (11), (12) and (21) monobasic bidentate type (7) or monobasic tridentate type (2), (3), (5), (6), (8), (14), (15), (16), (18), (19), (20) and (22) or dibasic tridentate type (5), (9) and (17) towards the metal ion. Molar conductances in DMF solution indicate that, the complexes are non-electrolytes. The e.s.r spectra of solid complexes (8) and (10) show axial type spectra with , d(x²-y²) ground state with significant covalent bond character. However, complex (12), shows an isotropic type, indicating a octahedral manganese(II) complex. Antibacterial and antifungal tests of the ligand and some of its metal complexes are also carried out and it has been observed that, the complexes are more potent bactericides and fungicides than the ligand.     

Synthesis and characterization of 3-methyl-5-oxo-N,1-diphenyl-4,5-dihydro-1-H-pyrazole-4-carbothioamide and its metal complexes

The molecular parameters have been calculated to confirm the geometry of 3-methyl-5-oxo-N,1-diphenyl-4,5-dihydro-1-H-pyrazole-4-carbothioamide, HL. The compound is introduced as a new chelating agent for complexation with Cr(III), Fe(III), Co(II), Ni(II) and Cu(II) ions. The isolated chelates were characterized by partial elemental analyses, magnetic moments, spectra (IR, UV–vis, ESR; ¹H NMR) and thermal studies. The protonation constant of HL (5.04) and the stepwise stability constants of its Co(II), Cu(II), Cr(III) and Fe(III) complexes were calculated. The ligand coordinates as a monobasic bidentate through hydroxo and thiol groups in all complexes except Cr(III) which acts as a monobasic monodentate through the enolized carbonyl oxygen. Cr(III) and Fe(III) complexes measured normal magnetic moments; Cu(II) and Co(II) measured subnormal while Ni(II) complex is diamagnetic. The data confirm a high spin and low spin octahedral structures for the Fe(III) and Co(II) complexes. The ESR spectrum of the Cu(II) complex support the binuclear structure. The molecular parameters have also been calculated for the Cu(II) and Fe(III) complexes. The thermal decomposition stages of the complexes confirm the MS to be the residual part. Also, the thermodynamic and kinetic parameters were calculated for some decomposition steps.     

First row transition metal complexes of (E)-2-(2-(2-hydroxybenzylidene) hydrazinyl)-2-oxo-N-phenylacetamide complexes

Manganese(II), iron(II), cobalt(II), nickel(II), copper(II), and chromium(III) complexes of (E)-2-(2-(2-hydroxybenzylidene)hydrazinyl)-2-oxo-N-phenylacetamide were synthesized and characterized by elemental and thermal (TG and DTA) analyses, IR, UV-vis and (1)H NMR spectra as well as magnetic moment. Mononuclear complexes are obtained with 1:1 molar ratio except [Mn(HOS)(2)(H(2)O)(2)] and [Co(OS)(2)](H(2)O)(2) complexes which are obtained with 1:2 molar ratios. The IR spectra of ligand and metal complexes reveal various modes of chelation. The ligand behaves as a monobasic bidentate one and coordination occurs via the enolic oxygen atom and azomethine nitrogen atom. The ligand behaves also as a monobasic tridentate one and coordination occurs through the carbonyl oxygen atom, azomethine nitrogen atom and the hydroxyl oxygen. Moreover, the ligand behaves as a dibasic tridentate and coordination occurs via the enolic oxygen, azomethine nitrogen and the hydroxyl oxygen atoms. The electronic spectra and magnetic moment measurements reveal that all complexes possess octahedral geometry except the copper complexes possesses a square planar geometry. From the modeling studies, the bond length, bond angle, HOMO, LUMO and dipole moment had been calculated to confirm the geometry of the ligands and their investigated complexes. The thermal studies showed the type of water molecules involved in metal complexes as well as the thermal decomposition of some metal complexes. The protonation constant of the ligand and the stability constant of metal complexes were determined pH-metrically in 50% (v/v) dioxane-water mixture at 298 K and found to be consistent with Irving-Williams order. Moreover, the minimal inhibitory concentration (MIC) of these compounds against Staphylococcus aureus, Escherechia coli and Candida albicans were determined.     

Synthesis,structural, and biological studies of some bivalent metal ion complexes with the tridentate Schiff base ligand

New complexes of a Schiff base derived from 2-hydroxy-5-chloroacetophenone and glycine with Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and UO₂(VI) have been synthesized. The ligand and the complexes have been characterized on the basis of analytical data, electrical conductance, IR, ESR, and electronic spectra, magnetic susceptibility measurements and thermogravimetric analysis. The ligand acts as a dibasic tridentate (ONO) donor molecule in all the complexes except the Zn(II) complex, where it acts as a monobasic bidentate (OO) donor. Antibacterial activities of the ligand and its metal complexes have been determined by screening the compounds against various Gram(+) and Gram(−) bacterial strains. The solid state d.c. electrical conductivity of the ligand and its complexes has been measured over 313–398 K and the complexes were found to be of semiconducting nature. The article is published in the original.     

Synthesis,characterization and biological activity of triaminoxime and its metal complexes

Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes of multifunctional triaminoxime have been synthesized and characterized by elemental analyses, IR, UV–Vis spectra, magnetic moments, ¹H- and ¹³C-NMR spectra for ligand and its Ni(II) complex, mass spectra, molar conductances, thermal analyses (DTA, DTG and TG) and ESR measurements. The IR spectral data show that the ligand is bi-basic or tri-basic tetradentate towards the metals. Molar conductances in DMF indicate that the complexes are non-electrolytes. The ESR spectra of solid copper(II) complexes [(HL)(Cu)₂(Cl)₂] · 2H₂O (2) and [(L)(Cu)₃(OH)₃(H₂O)₆] · 7H₂O (6) show axial symmetry of a d _{x²???y ²} ground state; however, [(HL)(Co)] (4) shows an axial type with d _Z ² ground state and manganese(II) complex [(L)(Mn)₃(OH)₃(H₂O)6] · 4H₂O (10) shows an isotropic type. The biological activity of the ligand and its metal complexes are discussed.     

Synthesis, spectral and thermal studies of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complex dyes based on hydroxyquinoline moiety

A series of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of azo-compounds containing hydroxyl quinoline moiety have been synthesized and characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic and ESR spectral studies. The results revealed the formation of 1:1 and 1:2 (L:M) complexes. The molar conductance data reveal that the chelates are nonelectrolyte. IR spectra indicate that the azodyes behave as monobasic bidentate or dibasic tetradentate ligands through phenolate or carboxy oxygen, azo N for 1:1 (L:M) complexes beside phenolate oxygen and quinoline N atoms for 1:2 (L:M) complexes. The thermal analyses (TG and DTA) as well as the solid electrical conductivity measurements are also studied. The molecular parameters of the ligands and their metal complexes have been calculated.     

Mixed Ligand Complexes of Ni(II) with Arylidene- Anthranilic Acids and Some Lewis Bases

Some binary and ternary complexes of Ni(II) with arylideneanthranilic acids and Lewis bases have been prepared and characterized by elemental analyses, IR spectra and X-ray powder diffraction. On the basis of the IR spectra it was found that the Schiff bases used act as monobasic bidentate ligands except for the ortho-hydroxy derivative which acts as a dibasic tridentate ligand. From X-ray analysis it is concluded that the binary Ni(II) chelates are isostructural, and the ternary Ni(II) complexes are also isostructural.     

Transition metal complexes of isonicotinic acid (2-hydroxybenzylidene)hydrazide

A new series of transition metal complexes of Schiff base isonicotinic acid (2-hydroxybenzylidene)hydrazide, HL, have been synthesized. The Schiff base reacted with Cu(II), Ni(II), Co(II), Mn(II), Fe(III) and UO2(II) ions as monobasic tridentate ligand to yield mononuclear complexes of 1:2 (metal:ligand) except that of Cu(II) which form complex of 1:1 (metal:ligand). The ligand and its metal complexes were characterized by elemental analyses, IR, UV-vis, mass and 1H NMR spectra, as well as magnetic moment, conductance measurements, and thermal analyses. All complexes have octahedral configurations except Cu(II) complex which has an extra square planar geometry distorted towards tetrahedral. While, the UO2(II) complex has its favour hepta-coordination. The ligand and its metal complexes were tested against one strain Gram +ve bacteria (Staphylococcus aureus), Gram -ve bacteria (Escherichia coli), and Fungi (Candida albicans). The tested compounds exhibited higher antibacterial activities.     

Synthesis, characterization and biological activities of Cu(II), Co(II), Mn(II), Fe(II), and UO2(VI) complexes with a new Schiff Base hydrazone: O-hydroxyacetophenone-7-chloro-4-quinoline hydrazone

The Schiff base hydrazone ligand HL was prepared by the condensation reaction of 7-chloro-4-quinoline with o-hydroxyacetophenone. The ligand behaves either as monobasic bidentate or dibasic tridentate and contain ONN coordination sites. This was accounted for be the presence in the ligand of a phenolic azomethine and imine groups. It reacts with Cu(II), Ni(II), Co(II), Mn(II), UO(2) (VI) and Fe(II) to form either mono- or binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, NMR, Mass, and UV-Visible spectra. The magnetic moments and electrical conductance of the complexes were also determined. The Co(II), Ni(II) and UO(2) (VI) complexes are mononuclear and coordinated to NO sites of two ligand molecules. The Cu(II) complex has a square-planar geometry distorted towards tetrahedral, the Ni(II) complex is octahedral while the UO(2) (VI) complex has its favoured heptacoordination. The Co(II), Mn(II) complexes and also other Ni(II) and Fe(III) complexes, which were obtained in the presence of Li(OH) as deprotonating agent, are binuclear and coordinated via the NNNO sites of two ligand molecules. All the binuclear complexes have octahedral geometries and their magnetic moments are quite low compared to the calculated value for two metal ions complexes and thus antiferromagnetic interactions between the two adjacent metal ions. The ligand HL and metal complexes were tested against a strain of Gram +ve bacteria (Staphylococcus aureus), Gram -ve bacteria (Escherichia coli), and fungi (Candida albicans). The tested compounds exhibited high antibacterial activities.     

Synthesis and spectroscopic characterization of indomethacin-Cd(II), Ce(III), and Th(IV) complexes: IR, 1H NMR,thermal, and biological studies

Solid complexes have been prepared and characterized by IR, UV-Vis, elemental analysis, and ¹H NMR. Indomethacin forms complexes with Cd(II), Ce(III), and Th(IV) ions in molar ratios (ligand: metal) (2: 1), (3: 1), and (4: 1), respectively. The IR spectra of the complexes suggest that the Indomethacin behaves as a monobasic monodentate ligand coordinated to the metal ions via the deprotonated carboxylate group. Prepared complexes exhibit higher antimicrobial activity against several microorganisms, compared to free ligand.     

Transition metal complexes of a Schiff base: synthesis,characterization, and antibacterial studies

Synthesis of a new Schiff base derived from 2-hydroxy-5-methylacetophenone and glycine and its coordination with compounds Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and UO₂(VI) are described. The ligand and complexes have been characterized on the basis of analytical, electrical conductance, infrared, ESR and electronic spectra, magnetic susceptibility measurements, and thermogravimetric analysis. The ligand is a dibasic tridentate (ONO) donor in all the complexes except Zn(II), where it is a monobasic bidentate (OO) donor. The solid state DC electrical conductivity of ligand and its complexes have been measured over 313–398 K, and the complexes were semiconducting. Antibacterial activities of ligand and its metal complexes have been determined by screening the compounds against various Gram (+) and Gram (?) bacterial strains.     

Synthesis,structural studies and bio-activity of some metal(II) complexes with glyoxal salicylaldehyde acyldihydrazones

Complexes of the type [M(gssdh)]Cl and [M(gspdh)]Cl, where M?=?Co(II), Ni(II), Cu(II), Zn(II) and Cd(II), Hgssdh?=?glyoxal salicylaldehyde succinic acid dihydrazone and Hgspdh?=?glyoxal salicylaldehyde phthalic acid dihydrazone, have been synthesized and characterized by elemental analyses, molar conductance, magnetic moments, electronic, ESR and IR spectra and X-ray powder diffraction studies. The metal complexes are insoluble in common organic solvents and are 1?:?1 electrolytes. The magnetic moment values and electronic spectra indicate a spin–free octahedral geometry for all Co(II), Ni(II) and Cu(II) complexes. ESR spectral parameters of Cu(II) complexes suggest an elongated tetragonally–distorted octahedral stereochemistry around copper. Both ligands are monobasic hexadentate ligands coordinating through three >C=O, two >C=N– and a deprotonated phenolate group to the metal. X-ray powder diffraction parameters for three of the complexes correspond to an orthorhombic crystal lattice. The complexes show appreciable activity against various fungi and bacteria.     

Synthesis,spectroscopic investigations,and biological activity of metal complexes of N-benzoylthiosemicarbazide

N-Benzoylthiosemicarbazide, HL, was obtained by fusion of benzoylhydrazide and ammonium thiocyanate. Reactions of HL with cobalt(II), nickel(II), copper(II), zinc(II), iron(III), cadmium(II), oxovanadium(IV), and dioxouranium(VI) in 1 : 1 molar ratio yield the corresponding complexes. The N-benzoylthiosemicarbazide may act as a neutral or monobasic bidentate ligand coordinated through NS or NO sites. The structures of the HL ligand and its complexes were identified by elemental analysis, infrared, electronic, mass, ¹H-NMR, and ESR spectra as well as magnetic susceptibility and molar conductivity measurements. Different geometries were obtained for the metal complexes. The ligand and its metal complexes were investigated for antibacterial and antifungal properties. Two Gram-positive bacteria, Staphylococcus aureus and Streptococcus pyogenes, two Gram-negative, bacteria, Pseudomonas fluorescens and Pseudomonas phaseolicola and two fungi, Fusarium oxysporum and Aspergillus fumigatus, were used in this study. The metal complexes were more effective than the free ligand.     

Spectral, thermal, kinetic, molecular modeling and eukaryotic DNA degradation studies for a new series of albendazole (HABZ) complexes

This work represents the elaborated investigation for the ligational behavior of the albendazole ligand through its coordination with, Cu(II), Mn(II), Ni(II), Co(II) and Cr(III) ions. Elemental analysis, molar conductance, magnetic moment, spectral studies (IR, UV-Vis and ESR) and thermogravimetric analysis (TG and DTG) have been used to characterize the isolated complexes. A deliberate comparison for the IR spectra reveals that the ligand coordinated with all mentioned metal ions by the same manner as a neutral bidentate through carbonyl of ester moiety and NH groups. The proposed chelation form for such complexes is expected through out the preparation conditions in a relatively acidic medium. The powder XRD study reflects the amorphous nature for the investigated complexes except Mn(II). The conductivity measurements reflect the non-electrolytic feature for all complexes. In comparing with the constants for the magnetic measurements as well as the electronic spectral data, the octahedral structure was proposed strongly for Cr(III) and Ni(II), the tetrahedral for Co(II) and Mn(II) complexes but the square-pyramidal for the Cu(II) one. The thermogravimetric analysis confirms the presence or absence of water molecules by any type of attachments. Also, the kinetic parameters are estimated from DTG and TG curves. ESR spectrum data for Cu(II) solid complex confirms the square-pyramidal state is the most fitted one for the coordinated structure. The albendazole ligand and its complexes are biologically investigated against two bacteria as well as their effective effect on degradation of calf thymus DNA.     

Conventional and microwave synthesis,spectral, thermal and antimicrobial studies of some transition metal complexes containing 2-amino-5-methylthiazole moiety

Schiff base metal complexes of Cr(III), Co(II), Ni(II) and Cu(II) derived from 5-chlorosalicylidene-2-amino-5-methylthiazole (HL¹) and 2-hydroxy-1-naphthylidene-2-amino-5-methylthiazole (HL²) have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ¹H-NMR, ESR, magnetic susceptibility, thermal, electrical conductivity and XRD analyses. The complexes exhibit coordination number 4 or 6. The complexes are coloured and stable in air. Analytical data reveal that all the complexes exhibit 1:2 (metal:ligand) ratio. IR data show that the ligand coordinates with the metal ions in a bidentate manner through the phenolic oxygen and azomethine nitrogen. FAB-mass and thermal data show degradation pattern of the complexes. The thermal behaviour of metal complexes shows that the hydrated complexes lose water molecules of hydration in the first step; followed by decomposition of ligand molecules in the subsequent steps. XRD patterns indicate crystalline nature for the complexes. The Schiff bases and metal complexes show good activity against the Gram-positive bacteria; Staphylococcus aureus and Gram-negative bacteria; Escherichia coli and fungi Aspergillus niger and Candida albicans. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases.     

Synthesis,characterization and biological activities of mononuclear and binuclear Fe(III) complexes with some symmetric and unsymmetric Schiff-base ligands

A series of mononuclear and binuclear Fe(III) complexes of some new symmetrical and unsymmetrical Schiff bases containing quinoline derivatives were synthesized and characterized by elemental and thermal analysis, conductance measurements and IR spectra. In mononuclear complexes, the unsymmetric Schiff bases are monobasic tetradentate towards the Fe(III) ion. However, in binuclear complexes, the symmetric Schiff-base ligands behave as monobasic bidentate towards each Fe(III) ion. The structure of the solid complexes are discussed and based on magnetic susceptibility measurements, electronic and ESR spectral studies. The biological activities of the ligands and their complexes are reported.