Concave Reagents 36: Transition Metal Complexes With Concave 1,10-phenanthrolines

Complexes between concave 1,10-phenanthrolines 1 and transition metal ions (Mn 2+ , Fe 2+ , Fe 3+ , Co 2+ , Ni 2+ , Cu + , Cu 2+ , Zn 2+ , Ag + , Cd 2+ ) have been synthesized and characterized by various methods including UV titration, NMR spectroscopy, EPR spectroscopy, cyclovoltammetry, microanalysis and X-ray analysis. The concave 1,10-phenanthrolines 1 form 1:1 complexes with the metal ions while the complexes of analogous, but non-bimacrocyclic 1,10-phenanthrolines such as 2 and 2,9-dimethyl-1,10-phenanthroline exist in varying stoichiometries.     

Synthesis,characterization, and catalytic activity of a new series of Ni(II), Cu(II), and Zn(II) complexes of N,N-O,O mixed-bidentate ligands for C–C cross-coupling reactions

Abstract

A new series of air stable transition metal(II) complexes [M(II)(L)(Phen)], [M(II)(L)(Pip)] (M?=?Ni, Cu, and Zn) (H₂L = 2,2′-methylenebis(4-nitrophenol)) (Phen =1,10-phenanthroline) (Pip?=?Piperazine) has been synthesized by incorporating the metal ion with bisphenol and 1,10-phenanthroline/piperazine ligands. The prepared metal complexes were characterized by FT-IR, UV–vis, ¹H NMR, EPR, and mass spectrometry. The metal(II) complexes were potent catalysts for Suzuki–Miyaura and Kumada–Corriu coupling of various aryl halides under optimized conditions.     

ZINC(II), CADMIUM(II), MERCURY(II) AND LEAD(II) SEMIQUINONE-TYPE COMPLEXES OF A NEW SCHIFF-BASE LIGAND: ANTIBACTERIAL STUDIES

Abstract

A new Schiff-base ligand LH₂, has been prepared by reaction of 2,9-diformv 1-1,10-phenan-throline with 2,3-diamino-l,4-naphthoquinone. The formation and characterization of complexes of Zn(II), Cd(II), Hg(II) and Pb(II) with the semi-oxidized ligand LH is described. The M(LH)X₂ (X = CI, Br and AcO) radical species are paramagnetic and the observed EPR signals in the solid state at room temperature, with g values close to the electron free g value are proof of the semiquinonic character of the ligand. The antibacterial activity of the ligand and the metal complexes prepared were tested against four bacteria strains and compared with the activity of penicillin.     

Determination of Metal Ions in Natural Waters by Flame-AAS after Preconcentration on a 5-Amino-1,3,4-Thiadiazole-2-Thiol Modified Silica Gel.

ABSTRACT

5-amino-1,3,4-thiadiazole-2-thiol groups attached on a silica gel surface have been used for adsorption of Cd(II), Co(II), Cu(II), Fe(III), Ni(II), Pb(II) and Zn(II) from aqueous solutions. The adsorption capacities for each metal ion were (in mmol.g^?1): Cd(II)= 0.35, Co(II)= 0.10, Cu(II)= 0.15, Fe(III)= 0.20, Hg(II)= 0.46, Ni(II)= 0.16, Pb(II)= 0.13 and Zn(II)= 0.15. The modified silica gel was applied in the preconcentration and quantification of trace level metal ions present in water samples (river, and bog water).     

Synthesis,characterization and fluorescence spectra of mononuclear Zn(II), Cd(II) and Hg(II) complexes with 1,10-phenanthroline-5,6-dione ligand

The mononuclear complexes of Zn(II), Cd(II) and Hg(II), [Zn(phen-dione)Cl₂], [Cd(phen-dione)Cl₂] and [Hg(phen-dione)Cl₂], where phen-dione?=?1,10-phenanthroline-5,6-dione, have been synthesized and characterized by elemental analysis and IR, ¹H?NMR and electronic absorption spectroscopies. The ν(C=O) of coordinated phen-dione ligands in these complexes shows that the phen-dione is not coordinated to metal ion from its C=O sites. Electronic spectra of the complexes show two absorption bands for intraligand transitions. These absorption bands show dependence on the dielectric constant of solvents. These complexes exhibit an intense fluorescence band around 545?nm in DMSO when the excitation wavelengths are 200?nm at room temperature.     

Metal Complexes of Saccharin with the N-(2-hydroxyethyl)-ethylenediamine Ligand: Synthesis,Characterization and Spectroscopic Examination. Crystal Structures of trans- Bis(Saccharinato)Bis{N-(2-hydroxyethyl)-Ethylenediamine} copper(II) and Cadmium(II)

The novel transition metal saccharinato complexes of N-(2-hydroxyethyl)-ethylendiamine (HydEt-en) have been synthesized and characterized by elemental analyses, magnetic moments, UV-Vis and IR spectra. Coordination behaviour of HydEt-en has been studied. The Mn(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) form mononuclear complexes, while the Fe(II) and Co(II) complexes are dimeric. The crystal structures of the [Cu(sac)₂(HydEt-en)₂] and [Cd(sac)₂(HydEt-en)₂] complexes, where sac is the deprotonated form of saccharin, were determined by x-ray diffraction. The metal ions are octahedrally coordinated by these ligands. The amine ligand acts as a bidentate N-donor ligand and its ethanol group is not involved in coordination. The sac ions coordinate through the deprotonated N as a monodentate ligand. The NH and OH groups of the amine ligand are involved in intra- and intermolecular hydrogen bonding with the carbonyl and sulphonyl oxygens of the sac ions to form a three-dimensional infinite network.     

Antimicrobial and anticancer activities of Schiff base ligand and its transition metal mixed ligand complexes with heterocyclic base

A new Schiff base ligand (HL) was prepared via a condensation reaction of quinoline‐2‐carboxaldhyde with 2‐aminophenol in a molar ratio of 1:1. Its transition metal mixed ligand complexes with 1,10‐phenanthroline (1,10‐phen) as co‐ligand were also synthesized in a 1:1:1 ratio. HL and its mixed ligand complexes were characterized using elemental analysis, infrared, ¹H NMR, mass and UV–visible spectroscopies, molar conductance, magnetic measurements, solid reflectance, thermal analysis, electron spin resonance and X‐ray diffraction. Molar conductance measurements showed that all complexes have an electrolytic nature, except Cd(II) complex. From elemental and spectral data, the formulae [M(L)(1,10‐phen)(H₂O)]Cl_x?nH₂O (where M = Cr(III) (x = n = 2), Mn(II) and Ni(II) (x = 1, n = 2), Fe(III) (x = n = 2), Co(II), Cu(II) and Zn(II) (x = 1, n = 2)) and [Cd(L)(1,10‐phen)Cl]?3H₂O for the metal complexes have been proposed. The geometric structures of complexes were found to be octahedral. Powder X‐ray diffraction reflected the crystalline nature of the complexes; however, the Schiff base is amorphous. HL and its mixed ligand complexes were screened against Gram‐positive bacteria (Streptococcus pneumoniae and Bacillus subtilis) and Gram‐negative bacteria (Pseudomonas aeruginosa and Escherichia coli). Antifungal activity was determined against Aspergillus fumigatus and Candida albicans, the data showing that most complexes had activity less than that of the Schiff base while Mn(II), Fe(III) and Ni(II) complexes showed no significant antifungal activity. The anticancer activity of HL and its metal complexes was also studied against breast and colon cell lines. The metal complexes showed IC₅₀ higher than that of HL, especially the Cu(II) complex which showed the highest IC₅₀ against breast cell line.     

Determination of metal ions by capillary electrophoresis using pre-column complexation with 1,10-phenanthroline

The capillary electrophoretic separation of Fe(II), Cu(II) and Zn(II) ions in an acidic buffer solution (pH 2.5) by complexation with 1,10-phenanthroline is investigated. As 1,10-phenanthroline is a neutral ligand, the positively charged metal complexes formed migrate in the same direction as the EOF, providing a rapid separation of metal ions in acidic buffers. The method was applied to the determination of metal ions in vitamin tablets. Received: 5 January 1998 / Revised: 27 March 1998 / Accepted: 15 May 1998     

Determination of metal ions by capillary electrophoresis using pre-column complexation with 1,10-phenanthroline

The capillary electrophoretic separation of Fe(II), Cu(II) and Zn(II) ions in an acidic buffer solution (pH 2.5) by complexation with 1,10-phenanthroline is investigated. As 1,10-phenanthroline is a neutral ligand, the positively charged metal complexes formed migrate in the same direction as the EOF, providing a rapid separation of metal ions in acidic buffers. The method was applied to the determination of metal ions in vitamin tablets. Received: 5 January 1998 / Revised: 27 March 1998 / Accepted: 15 May 1998     

Transition metal complexes of Schiff base ligand based on 4,6-diacetyl resorcinol

Novel Schiff base ligand based on the condensation of 4,6-diacetyl resorcinol with 2-amino-4-methylthiazole in addition to its metal complexes with Cr (III), Mn (II), Fe (III), Co (II), Ni (II), Cu (II), Zn (II) and Cd (II) ions have been synthesized. The structure, electronic properties, and thermal behaviour of Schiff base and its metal complexes have been studied by elemental analysis, mass, ¹H NMR, IR spectra, thermal analysis, and theoretically by density function theory. The ligand acted as mononegative bidentate (NO) ligand and all complexes showed octahedral geometry except Cu (II) showed tetrahedral geometry as indicated from the spectral and magnetic studies. The Cu (II), Zn (II) and Cd (II) complexes were non electrolytes while the rest of the complexes were electrolytes. The antibacterial plus anticancer activities of the parent Schiff base and its metal complexes were screened. In addition, the molecular docking study was performed to explore the possible ways for binding to Crystal Structure of Human Astrovirus capsid protein (5ibv) receptor.     

Synthesis,characterization and antimicrobial activity of homodinuclear complexes derived from 2,6- bis [3′-methyl- 2′-carboxamidyliminomethyl(6′,7′)benzindole]-4-methylphenol,an end-off compartmental ligand

End-off compartmental pentadentate Schiff base, 2,6-bis[3′-methyl-2′-carboxamidyliminomethyl(6′,7′)benzindole]-4-methylphenol is synthesized and characterized by 2D NMR experiments and mass spectral techniques. The homodinuclear phenalato bridged end-off compartmental Schiff-base complexes Cu(II), Co(II), Ni(II), Mn(II), Fe(III), VO(IV), Zn(II), Cd(II) and Hg(II) have been prepared by the template method using the precursors 2,6-diformyl-4-methylphenol, 3-methyl(6′,7′)-2-benzindolehydrazide and metal chlorides in 1?:?2?:?2 ratio. The complexes are characterized by IR, NMR, UV-vis, FAB-mass, ESR and TGA techniques. Ni(II), Mn(II) and Fe(III) complexes have octahedral geometry, whereas the Cu(II), Co(II), VO(IV), Zn(II), Cd(II) and Hg(II) complexes have square pyramidal geometry. Low magnetic moment values for Cu(II), Co(II), Ni(II), Mn(II), Fe(III) and VO(IV) complexes indicate antiferromagnetic spin-exchange interaction between two metal centers. The metal complexes have been screened for their antibacterial activity against Escherichia coli and Staphyloccocus aureus and antifungal activity against Aspergillus niger and Fusarium oxysporum.     

Phenoxo-bridged symmetrical homobinuclear complexes derived from an “end-off” compartmental ligand, 2,6- bis [5′-chloro-3′-phenyl- 1H -indole-2′-carboxamidyliminomethyl]-4-methylphenol

A compartment ligand 2,6-bis[5′-chloro-3′-phenyl-1H-indole-2′-carboxamidyliminomethyl]-4-methylphenol was prepared and homobinuclear phenol-bridged Cu(II), Ni(II), Co(II), Zn(II), Cd(II), Hg(II), Fe(III), and Mn(II) complexes have been prepared by the template method using the precursors 2,6-diformyl-4-methylphenol, 5-chloro-3-phenylindole-2-carbohydrazide and metal chlorides in 1 : 2 : 2 ratio, respectively. The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibility data, IR, NMR, FAB mass and ESR spectra, TGA, and powder XRD data. Cu(II), Co(II), Zn(II), Cd(II) and Hg(II) complexes exhibit square pyramidal geometry whereas Ni(II), Mn(II), and Fe(III) complexes are octahedral. Low magnetic moment values for Cu(II), Ni(II), Co(II), Fe(III), and Mn(II) complexes show antiferromagnetic spin-exchange interaction between two metal centers in binuclear complexes. The ligand and its complexes were tested for antibacterial activity against Escherichia coli and Staphyloccocus aureus, and antifungal activity against Aspergillus niger and Candida albicans.     

The separation of zinc(II) and cadmium(II) by liquid-liquid extraction

The extraction of Zn(II) and Cd(II) from thiocyanate solutions with bis-2-ethylhexyl sulphoxide (B₂EHSO) in benzene as an extractant has been studied by tracer techniques. For comparison, extraction has also been carried out with tributylphosphate (TBP). The extraction data have been analysed by both graphical and theoretical methods by taking into account complexation of the metal in the aqueous phase by inorganic ligands and plausible complexes extracted into the organic phase. The results demonstrate that Zn(II) is extracted as Zn(SCN)₂·2B2EHSO and Zn(SCN)₂·2TBP. In the case of Cd(II), the extracted species are Cd(SCN)₂·4B2EHSO/4TBP. The synergistic extraction of Zn(II) and Cd(II) with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP) and B2EHSO or TBP or trioctylphosphine oxide (TOPO) from acetate buffer solutions has also been investigated. Zn(II) is extracted as Zn(PMBP)₂·B2EHSO/TBP/TOPO. On the other hand, Cd(II) is found to be not extracted with these mixed-ligand systems under the experimental conditions. These results also demonstrate the mutual separation of Zn(II) and Cd(II) using the synergistic extraction with HPMBP in the presence of various neutral oxodonors.     

Synthesis,characterization and susceptibility of bacteria against Sulfamethoxydiazine complexes of copper(II), zinc(II), nickel(II), cadmium(II), chromium(III) and iron(III)

Complexes of sulfamethoxydiazine with Cu(II), Zn(II), Ni(II), Cd(II), Cr(III) and Fe(III) have been synthesized and characterized on the basis of conductivity measurements, elemental analyses, UV, IR, ¹H?NMR and thermal studies. It is shown that sulfamethoxydiazine behaves as a bidentate ligand, binding the metal ion through the sulfonyl oxygen and sulfonamide nitrogen. In vitro susceptibility tests of these complexes against Escherichia coli, Bacillus subtilis, Proteus vulgaris and Staphylococcus aureus were carried out. The results show that the antibacterial activities of the complexes of Zn(II), Cu(II), Cr(III) and Fe(III) are, in general, stronger than that of sulfamethoxydiazine, while the complexes of Cd(II) and Ni(II) are less active.     

Design of phenanthrimidazole-pendant cyclam and cyclen macrocyclic complex ligands as inorganic hosts: Photophysics,electrochemistry, and bimetallic complex formation

Novel ruthenium(II)bpy complexes of the phenanthrimidazole-pendant cyclen and cyclam macrocyclic ligands were synthesized as inorganic host molecules. Inorganic host design was planned as a “complex ligand” form because of its tetraaza macrocyclic unit, which has the ability to coordinate to the metals. Photophysical properties and metal selectivity of inorganic hosts RuL1A and RuL2 complex ligands were investigated by UV-vis and fluorescence spectroscopy in aqueous medium. Among Ag(I), Li(I), Na(I), K(I), Cd(II), Cr(II), Fe(II), Hg(II), Ni(II), Pb(II), Zn(II), Cu(II), Mn(III), and Co(III) metal ions, Fe(II) addition causes spectral changes for both RuL1A and RuL2 complex ligands. Electrochemical studies were performed for RuL1B and also for cis-[Ru(bpy) ₂ Cl ₂ ] . Bimetallic complexes [[Ru(bpy)₂([Ni(2-(4-((1,4,8,11-tetraazacyclotetradecan-1-yl)methyl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline])](ClO₄)₄, RuL1-NiA and [Ru(bpy)₂([Ni(2-(4-((1,4,8,11-tetraazacyclotetradecan-1-yl)methyl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline])]Cl₄, RuL1-NiB solid complexes were also obtained by the reaction of the RuL1B and Nickel(II).     

Synthesis and complexation of 1,4,7-oxadithiononane-5,6-dionedioxime

A new vic-dioxime 1,4,7-oxadithiononane-5,6-dionedioxime (H₂L) was prepared from reaction of 2,2-oxydiethanthiol with dichloroglyoxime. Mononuclear complexes of H₂L with Ni(II), Co(II), Cu(II), Zn(II), and Cd(II) were also prepared and their structures were determined by means of ¹H?NMR, ¹³C?NMR, IR, and mass spectroscopy. Ni(II), Co(II), and Cu(II) form square planar complexes of 1?:?2 molar ratio of metal to ligand through N,N-chelation, while Zn(II) and Cd(II) form 1?:?1 tetrahedral complexes with a N,O-chelation.     

Synthesis,Spectroscopic and Magnetic Studies on Metal Complexes of 5-Methyl-3-(2-Hydroxyphenyl)Pyrazole

A tridentate ONN donor ligand, 5-methyl-3-(2-hydroxyphenyl)pyrazole; H₂L, was synthesized by reaction of 2-(3-ketobutanoyl)phenol with hydrazine hydrate. The ligand was characterized by IR, ¹H NMR and mass spectra. ¹H NMR spectra indicated the presence of the phenolic OH group and the imine NH group of the heterocyclic moiety. Different types of mononuclear metal complexes of the following formulae [(HL)₂M][sdot]xH₂O (M=VO, Co, Ni, Cu, Zn and Cd), [(HL)₂M(H₂O)₂] (M=Mn and UO₂) and [(HL)LFe(H₂O)₂] were obtained. The Fe(III) complex, [(HL)LFe(H₂O)₂] undergoes solvatochromism. Elemental analyses, IR, electronic and ESR spectra as well as thermal, conductivity and magnetic susceptibility measurements were used to elucidate the structures of the newly prepared metal complexes. A square-pyramidal geometry is suggested for the VO(IV) complex, square-planar for the Cu(II), Co(II) and Ni(II) complexes, octahedral for the Fe(III) and Mn(II) complexes and tetrahedral for the Zn(II) and Cd(II) complexes, while the UO₂(VI) complex is eight-coordinate. Transmetallation of the UO₂(VI) ion in its mononuclear complex by Fe(III), Ni(II) or Cu(II) ions occurred and mononuclear Fe(III), Ni(II) and Cu(II) complexes were obtained. IR spectra of the products did not have the characteristic UO₂ absorption band and the electronic spectra showed absorption bands similar to those obtained for the corresponding mononuclear complexes. Also, transmetallation of the Ni(II) ion in its mononuclear complex by Fe(III) has occurred. The antifungal activity of the ligand and the mononuclear complexes were investigated.     

Ionic strength effect on the liquid–liquid extraction of zinc(II) and cadmium(II) from sulphate medium by 1-phenyl-3-methyl-4-benzoylpyrazol-5-one in chloroform

The liquid–liquid extraction of zinc(II) and cadmium(II) from sulphate medium by 1-phenyl-3-methyl-4-benzoylpyrazol-5-one (HPMBP) in chloroform is studied. The ionic strength effect of the aqueous phase shows that the extraction of the metal increases with decreasing concentration of sulphate. At initially of about 10^?4?M with three different sulphate concentrations 0.033, 0.16 and 0.33?M in the aqueous phase, Zn(II) and Cd(II) are extracted as the complexes Zn(PMBP)₂ and Cd(PMBP)₂. Sulphate complexes of Zn(II) and Cd(II) are formed in the aqueous phase. The metal–sulphate interaction has been made in evidence by using the Debye–Huckel extended limiting law of ionic activity coefficient.     

SYNTHESIS AND CHARACTERIZATION OF Fe(III), Co(III), Cu(II) AND Zn(II) COMPLEXES OF N-2,4-HYDROXYBENZAL-D-GLUCOSAMINE

Abstract

The Schiff base N-2,4-dihydroxybenzal-D-glucosamine (L), and its Fe(III), Co(III), Cu(II) and Zn(II) complexes have been synthesized and characterized. Magnetic moments suggest that all complexes are high-spin. The Cu(II) chelate in DMF solution has a distorted tetrahedral structure, as shown by ESR and electronic spectra. Detailed studies have been made concerning the solution equilibrium of L with transition metal ions. Stabilities of the complexes are in accord with the Irving-Williams series.     

BINDING ABILITY OF OXINE-LIKE LIGANDS. POTENTIOMETRIC AND POLAROGRAPHIC STUDY ON Ni(II), Co(II), Zn(II) AND Cd(II) COMPLEXES OF 9-HYDROXYPYRIDO(1,2,-α)PYRIMIDIN-4-ONE

Abstract

Potentiometric and polarographic studies of metal ion coordination with 9-hydroxypyrido[1,2-α]pyrimidin-4-one (HPP) with Ni(II), Zn(II), Co(II) and Cd(II) ions have been carried out. For comparison, stability constants with 8-hydroxy-imidazo[1,2-α]pyridine (HIP) were also measured. Due to the low solubility of the latter ligand complexes, measurements were made also in dioxan/water solutions. In the case of both ligands the coordination mode is the same. The oxine-like binding via {N, O^?} donor set leads to formation of stable ML and ML₂ complexes. Stability constants clearly indicate that both ligands are very effective and the HPP, having a more favourable position of the electron pair on nitrogen, forms stronger complexes with smaller metal ions i.e., Ni(II), Zn(II) and Co(II). Cd(II) is better fitted to the HIP donor set.