Synthesis,characterization and antimalarial activity of new iridium–chloroquine complexes

Chloroquine base (CQ) reacts with [Ir(COD)Cl]₂ and IrCl₃ · 3H₂O to yield of Ir(CQ)Cl(COD) (1) and Ir₂Cl₆(CQ) · 3H₂O (2), respectively. Reaction of [Ir(COD)Cl]₂ with CQ in the presence of NH₄PF₆ leaded to [Ir(CQ)(Solv)₂]PF₆ (3). The three new iridium–CQ complexes were characterized by a combination of elemental analysis, IR and NMR spectroscopies and evaluated in vitro against Plasmodium beghei. Comparison of the IC₅₀ values obtained with the experimental compounds with that determined for chloroquine diphosphate indicated a higher activity for complex 2, while complexes 1 and 3 showed a similar and lower activity, respectively.     

Ni(II), Co(II), and Cu(II) complexes incorporating 2-pyrazinecarboxylic acid：Synthesis,characterization, electrochemical evaluation,and catalytic activity for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones

Three complexes containing 2-pyrazinecarboxylate (pzca–), including [Ni(pzca)2(H2O)2], [Co(pzca)2(H2O)2], and [Cu(pzca)2(H2O)2], have been synthesized and characterized using physico-chemical and spectroscopic methods. Furthermore, the structure of each complex was determined by single-crystal X-ray diffraction. All three complexes have an octahedral geometry, where the metal ion chelated by two carboxylate oxygens, two nitrogen atoms belonging to pyrazinic acid molecules, and two oxygen atoms of two water molecules. The catalytic activities of these complex-es were also investigated in the green synthesis of 2H-indazolo[2,1-b]phthalazine-triones by the reaction of hydrazine hydrate with an arylaldehyde, phthalic anhydride, and dimedone in acetic acid.     

Microwave assisted synthesis and characterization of N,N′-bis(salicylaldehydo)ethylenediimine complexes of Mn(II), Co(II), Ni(II), and Zn(II)

Microwave chemistry is a green chemical method that improves reaction conditions and product yields while reducing solvent amounts and reaction times. The main aim of this article is to synthesize the tetradentate N₂O₂ ligand [HO(Ar)CH=N–(CH₂)₂–N=CH(Ar)OH] and manganese(II), cobalt(II), nickel(II), and zinc(II) complexes of the type ML by classical and microwave techniques. The resulting Schiff base and its complexes are characterized by ¹H NMR, infrared, elemental analysis, and electronic spectral data. The ligand and its Co(II) and Mn(II) complexes were further identified by X-ray diffraction and mass spectra to confirm the structure. The results suggest that the metal is bonded to the ligand through the phenolic oxygen and the imino nitrogen.     

Synthesis,characterization, spectral studies and antifungal activity of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 3,3′-bis[N,N,di(carboxymethyl)-aminomethyl]- o -cresol sulphonphthalein

Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of the type Na₄[ML(H₂O)₂] of the ligand, 3,3′-bis[N,N-di(carboxymethyl)-aminomethyl]-o-cresol sulphonphthalein (Xylenol Orange, Na₄H₂L), have been synthesized and characterized by different physico-chemical (elemental analyses, solubility, electrolytic conductances, magnetic susceptibility measurements) and spectral (u.v.-vis, i.r., e.s.r., and powder X-ray diffraction) techniques for their structure determination. The data suggest 1?:?1 (M?:?L) compositions and octahedral geometries around M(II) except for Cu(II). Antifungal activity of the complexes measured against ten fungi show significant activity against Alternaria brassicicola, Alternaria solanai, Cercospora species and Helminthosporium oryzae and moderate antifungal activity against Curvularia species, Curvularia lunata, Curvularia penniseti, Colletotrichum capsici, Aspergillus niger, Aspergillus flavus Erysiphae pisi and Fusarium udum fungi.     

Antimicrobial studies of N - N ′-dicarboxydiethyloxamide and its Co(II), Ni(II), Cu(II) and Zn(II) complexes

Neutral complexes of Cu(II), Ni(II), Co(II), and Zn(II) have been synthesized from the oxamide-based ligand derived from leucine and diethyloxalate. The structural features have been deduced from their microanalytical, IR, UV/Vis, mass, ¹H and ¹³C NMR spectral data. The Co(II) and Ni(II) chelates have octahedral geometries and the Cu(II) chelate is a square-pyramidal geometry. The non-electrolytic and monomeric nature of the complexes is shown by their magnetic susceptibility and low conductance data. The biological activities of the ligand and its metal chelates against gram-positive and negative bacteria and fungi are also reported. All the compounds are antimicrobially active and show higher activity than the free ligand.     

Synthesis,characterization, and crystal structure of Ni(II) and Cu(II) complexes with N-furoyl-N′,N′-diethylthiourea: antifungal activity

The complexes cis-bis(N-furoyl-N′,N′-diethylthioureato-k ²O,S)nickel(II) and cis-bis(N-furoyl-N′,N′-diethylthioureato-k ²O,S)copper(II) were prepared by the reaction of metal acetate with the corresponding acylthiourea derivative. The complexes were characterized by IR, ¹H-NMR, ¹³C-NMR, and single-crystal X-ray diffraction. Both complexes show two furoylthiourea ligands bonded to metal to form a four-coordinate complex with square-planar geometry. The antifungal activity of the prepared complexes was studied against the phytopathogenic fungi Botrytis cinerea and Colletotrichum gloeosporioides, responsible for important plant diseases.     

Synthesis and characterization of new D-π-D type Schiff base ligands and its complexes with Cobalt(II), Ruthenium(II)

A Schiff base ligands, N-{(1E,2E)-3-[4-(dimethylamino)phenyl]prop-2-en-1-ylidene}-1,10-phenanthrolin-5-amine(mpa) and (1E,2E)-3-[4-(dimethylamino)phenyl]acrylaldehyde9H-fluoren-9-ylidenehydrazone(mfh), have been synthesized from the reaction of 4,5-diazafluorenone-9-hydrazone and 5-amino-1,10-phenanthroline with 4-(dimethylamino)cinnamaldehyde. The Co(II) and Ru(II) complexes of the ligands were prepared and characterized. The metal-to-ligand ratio of the Co(II) complex was found to be 2: 1 and that of the Ru(II) complex was found to be 1: 1. The ligands and complexes have been characterized by FTIR, UV-visible, ¹H NMR and fluorescence spectra, as well as, elemental analyses, TGA-DSC-DTG and mass spectra.     

Interaction of Co(II), Ni(II), Cu(II), and Zn(II) with N,N′-(aldose)2-thiocarbohydrazide: synthesis,electrochemistry, and spectral characterization

Complexes of Co(II), Ni(II), Cu(II), and Zn(II) with N,N′-(aldose)₂–thiocarbohydrazide (LH₂) were synthesized, isolated as solid products and characterized by analytical means as well as by spectral techniques, FTIR, ¹H NMR, EPR, UV spectroscopy, and CD. All the metal ions formed M[LH]X complexes. Molar conductance values in DMF indicate non-electrolytic complexes. In DMSO with tetramethylammonium chloride supporting electrolyte, the copper complex displays irreversible cyclic voltammetric responses with E _p near ?0.621 and 0.461 V versus Ag/AgCl at scan rate of 0.1 V s^?1. Probable structures for the complexes are proposed.     

The vibrational spectra of complexes with planar monothio-oxamides—I. The Ni(II), Pd(II), Pt(II), Cu(II) and Zn(II) complexes of N,N′-dimethylmonothio-oxamide

The new complexes M(LH)₂ (M = Pd,Pt), ML(M = Pd,Cu) and ML · H₂O (M = Ni,Zn), where LH₂ = N,N′-dimethylmonothio-oxamide, have been prepared. The complexes were characterized by metal analyses, thermal methods and spectral (i.r., Raman, u.v.—vis.) studies. The vibrational analyses of the complexes are given using NH/ND, CH₃/CD₃ and metal isotopic substitutions. The Ni(II), Pd(II), Pt(II) and Cu(II) compounds are square planar. The monoanion LH⁻ shows a chelated bidentate S,O-coordination, while the doubly deprotonated L²⁻ acts as a bridging S,N/N,O-tetradentate ligand giving polymeric structures.     

Synthesis,characterization, and investigation of catalytic activity of copper(II) porphyrin graphene oxide for azide–alkyne cycloaddition

Research on Chemical Intermediates - A covalently cross-linked graphene oxide (GO) catalyst was prepared by a cross-linking process using nucleophilic reaction of copper(II)‐coordinated...     

Synthesis,characterization and biological activity of copper(II) complexes with ligands derived from β-amino acids

Transition Metal Chemistry - Two copper(II) complexes with ligands derived from β-amino acids, 2-(1-aminocyclohexyl)acetic acid L1 and 2-(1-amino-4-(tert-butyl)cyclohexyl)acetic acid L2, were...     

Synthesis and spectroscopic studies of new Cu(II), Ni(II), VO(IV) and Zn(II) complexes with N,N′-bis(2-hydroxynaphthalin-1-carbaldehydene)-1,2-bis-(o-aminophenoxy)ethane

A novel tetradentate, N₂O₂-type Schiff base, synthesized from 1,2-bis-(o-aminophenoxy)ethane and 2-hydroxynaphthalin-1-carbaldehyde, forms stable complexes with transition metal ions such as Cu(II), Ni(II), VO(IV) and Zn(II) in DMF. Microanalytical data, elemental analyses, magnetic measurements, ¹H NMR, UV, visible and IR-spectra as well as conductance measurements were used to confirm the structures.     

Synthesis,crystal structure,thermal decomposition,and XPS studies of homo and heterotrinuclear Cu(II)–Cu(II)–Cu(II) and Cu(II)–Ni(II)–Cu(II) complexes obtained from salpn type ligands

In this study, a mononuclear CuL complex was prepared by the use of bis-N,N′-(salicylidene)-1, 3-propanediamine (LH₂) and Cu²⁺ ion. NiCl₂ and NiBr₂ salt were treated with this complex in dioxanewater medium and two new complexes [(CuL)₂NiCl₂(H₂O)₂] and [(CuL)₂NiBr₂(H₂O)₂)] with Cu(II)–Ni(II)–Cu(II) nucleus structure were obtained. In addition to this bis-N,N′-(2-hydroxybenzyl)-1,3-diaminopropane (L^HH₂) was prepared by the reduction of LH₂ with NaBH₄ in MeOH medium. The treatment of this reduced complex with Cu²⁺ ion resulted a complex [(CuL^H)₂CuCl₂] with a structure of Cu(II)–Cu(II)–Cu(II). The complexes prepared were characterized by the use of elemental analysis, IR spectroscopy, thermogravimetric and X-ray diffraction methods. The crystal structures of [(CuL)₂NiBr₂(H₂O)₂] (СIF file CCDC 1448402) and [(CuL^H)₂CuCl₂] (СIF file CCDC 1448401) complexes were elucidated. It was found that halogen ions are coordinated to terminal Cu²⁺ ions which are in a distorted square pyramid coordination sphere. It was determined that the central Cu(II), which joins terminal square pyramidal Cu(II), was coordinated only by the phenolic oxygens of the ligand while the central Ni(II) was coordinated by two phenolic oxygens of the organic ligand and two water molecules. These complexes were investigated by XPS and it was found that the terminal and central Cu²⁺ ions were different in Cu(II)–Cu(II)–Cu(II) complex. Also, the thermal degradation of the CuLH complex unit was observed to exothermic in contrast to the expectations.

     

Synthesis and characterisation of Co(II), Ni(II), Zn(II) and Cd(II) complexes with 5-bromo-N,N′-bis-(salicylidene)-o-tolidine

New complexes of type [M(HL)(CH₃COO)(OH₂)_m]·nH₂O (where M:Co, m = 2, n = 2; M:Ni, m = 2, n = 1.5; M:Zn, m = 0, n = 2.5 and M:Cd, m = 0, n = 0; H₂L:5-bromo-N,N′-bis-(salicylidene)-o-tolidine) have been synthesized and characterized by microanalytical, IR, UV–Vis-NIR and magnetic data. Electronic spectra of Co(II) and Ni(II) complexes are characteristic for an octahedral stereochemistry. The IR spectra indicate a chelate coordination mode for mono-deprotonated Schiff base and a bidentate one for acetate ion. The thermal transformations are complex according to TG and DTA curves including dehydration, acetate decomposition and oxidative degradation of the Schiff base. The final product of decomposition is the most stable metallic oxide.     

Preparation, spectral and thermal properties of Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) complexes with iodosubstituted 2,2′-dipyrrolylmethene

Complexes [ML₂] of cobalt(II), nickel(II), copper(II), zinc(II), and cadmium(II) with asymmetrically substituted (E)-3-ethyl-5-[(4-iodo-3,5-dimethyl-2H-pyrrol-2-ylidene)methyl]-2,4-dimethyl-1H-pyrrole (HL) have been prepared and characterized for the first time. The spectral properties, stability in solutions and in the solid phase at elevated temperature of the complexes have been studied. The effects of complexing metal ion and the reaction medium on the spectral luminescent properties (absorptivity, quantum yield, fluorescence lifetime, and the radiation constant) and on thermal destruction of the [ML₂] complexes have been discussed.     

Metal-based antibacterial agents: synthesis,characterization, and in vitro biological evaluation of cefixime-derived Schiff bases and their complexes with Zn(II), Cu(II), Ni(II), and Co(II)

The zinc(II), copper(II), nickel(II), and cobalt(II) complexes of Schiff bases, obtained by the condensation of cefixime with furyl-2-carboxaldehyde, thiophene-2-carboxaldehyde, salicylaldehyde, pyrrol-2-carboxaldehyde, and 3-hydroxynaphthalene-2-carboxaldehyde, were synthesized and characterized by their elemental analyses, molar conductances, magnetic moments, IR, and electronic spectral measurements. Analytical data and electrical conductivity measurements indicated the formation of M?:?L (1?:?2) complexes, [M(L)₂(H₂O)₂] or [M(L)₂(H₂O)₂]Cl₂ [where M?=?Zn(II), Cu(II), Ni(II), and Co(II)] in which ligands are bidentate via azomethine-N and deprotonated-O of salicyl and naphthyl, furanyl-O, thienyl-S, and deprotonated pyrrolyl-N. The magnetic moments and electronic spectral data suggest octahedral complexes. The synthesized ligands, along with their metal complexes, were screened for their antibacterial activity against different bacterial strains. The studies show the metal complexes to be more active against one or more species as compared to the uncomplexed ligands.     

Template synthesis and spectroscopic characterization of 16-membered [N4] Schiff-base macrocyclic complexes of Co(II), Ni(II), Cu(II), and Zn(II): in vitro DNA-binding studies

Template condensation between o-phthalaldehyde and 3,4-diaminotoluene resulted in mononuclear 16-membered tetraimine macrocyclic complexes, [MLCl₂] [M?=?Co(II), Ni(II), Cu(II), and Zn(II)]. The proposed stoichiometry and the nature of the complexes have been deduced from elemental analyses, mass spectra, and molar conductance data. The macrocyclic framework has been inferred from ν(C=N) and ν(M–N) bands in the IR spectra and the resonances observed in ¹H and ¹³C-NMR spectra. Octahedral geometry has been assigned for all these complexes on the basis of position of the bands in electronic spectra and magnetic moment data; distorted octahedral geometry has been assigned for the Cu(II) complex on the basis of EPR data. The low-conductivity data of all the complexes suggest their non-ionic nature. Interaction of these complexes with calf-thymus DNA (CT DNA) has been examined with fluorescence quenching experiments, which show that the complexes are avid binders of CT DNA.     

Synthesis,characterization and antimicrobial activity studies of N - N ′-tetracarboxydiethyloxamide ligand and its metal(II) complexes

N-N′-tetracarboxydiethyloxamide (hereafter abbreviated as H₆L) was prepared by using L-aspartic acid and diethyl oxalate (DEO). A series of binuclear complexes of divalent metal chlorides viz. Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) with H₆L have been prepared. Spectral studies (IR, UV and NMR) magnetic susceptibility, elemental analysis and molar conductance measurements confirm the formation of binuclear complexes, [M₂H₂L]/[M₂H₂L?·?4H₂O]. Electronic absorption spectra and magnetic susceptibilities suggest square-planar stereochemistry for Cu(II) and tetrahedral for Zn(II) complexes. Mn(II), Co(II), and Ni(II) coordinate two molecules of water and consequently show octahedral geometry. The in vitro antimicrobial activity of the synthesized compounds is discussed against bacterial strains such as S. aureus, S. epididermis, K. pneumonia, S. typhi, P. aerugenosa, and B. subtilis A. brasilense. The metal complexes show higher activity against all the microorganisms than the ligand.     

Redox reactions of peroxo terpyridine complexes of Cu(II), Zn(II), and Cu(II)?Zn(II): A pulse radiolysis study

The reactions of e_aq⁻, CH₂OH·, (CH₃)₂COH·, CO, OH· and N₃· radicals with peroxo terpyridine complexes of Cu(II), Zn(II), and Cu(II) Zn(II) in aqueous solution were investigated by pulse radiolysis. The primary products from the reduction and oxidation of the macrocyclic complexes were assigned a radical nature by comparing their optical spectra with those of Cu(I), Zn(I), and Cu(III) species. Such metal–ligand radical products undergo disproportionation that does not lead to the formation of Cu(0) or colloidal copper. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 92–98, 2000     

Synthesis, characterization and anticancer activity of new chiral Pd(II)-complexes derived from unsymmetrical α-diimine ligands

A set of new diastereopure unsymmetrical α-diimine ligands 2a-d derived from methylglyoxal and optically pure primary amines 1a-d afforded the new chiral Pd(II)-complexes (S,S)-3a, (S,S)-3b, (S,S)-3c, and (1S, 2S, 3S, 5R)-3d. All compounds have been characterized by IR, ¹H, and ¹³C NMR spectroscopies along with MS-FAB⁺ spectrometry. The crystal and molecular structure for the complexes 3a, 3b and 3d have been fully confirmed by single-crystal X-ray studies. Likewise, complexes 3a-d have also been screened for their in vitro cytotoxicity against different classes of cancer: leukemia (K-562 CML), colon cancer (HCT-15), human breast adenocarcinoma (MCF-7), central nervous system (U-251 Glio) and prostate cancer (PC-3) cell lines.