Synthesis,crystal structure,fluorescence, electrochemical property,and SOD-like activity of an unexpected nickel(II) complex with a quinazoline-type ligand

An unexpected mononuclear Ni(II) complex, [Ni(L²)₂]·CH₃OH (HL² = 1-(2-{[(E)-3,5-dichloro-2-hydroxybenzylidene]amino}phenyl)ethanone oxime), has been synthesized via complexation of Ni(II) acetate tetrahydrate with HL¹. HL¹ and its corresponding Ni(II) complex were characterized by IR, ¹H-NMR spectra, HRMS, as well as by elemental analysis, UV–vis, and emission spectroscopy. The crystal structure of the complex has been determined by single-crystal X-ray diffraction. Each complex links two other molecules into an infinite 1-D chain via intermolecular hydrogen bonds. Moreover, the electrochemical properties of the nickel complex were studied by cyclic voltammetry. Superoxide dismutase-like activities of HL¹ and Ni(II) complex were also investigated.     

Synthesis,crystal structures,antibacterial activities,and fluorescence properties of Schiff base ligand and its nickel(II) complex

A complex [Ni(L · CH₃OH)₂] · CH₃OH was synthesized, in which a Schiff base ligand HL · CH₃OH, was derived from condensation of 1-phenyl-3-methyl-4-(p-methylbenzoyl)-5-pyrazolone with L-Valine methyl ester. They were characterized by IR and single crystal X-ray diffraction. The ligand contains three independent molecules L · CH₃OH. The complex has a dissociative methanol and nickel six-coordinated compound. Every fragment is a distorted octahedron with four oxygen atoms and two nitrogen atoms. The HL · CH₃OH ligand and its complex have been tested in vitro to evaluate their antibacterial activity against bacteria Escherichia coli and Bacillus subtilis. It has been found that the complex has higher activity than the corresponding free ligand HL · CH₃OH against the same bacteria. The HL · CH₃OH ligand and its complex have been tested by liquid fluorescent. It has been found that the complex has higher fluorescence property than ligand.     

Synthesis,characterization and crystal structure of a novel thiazoline/thiazolidine azine ligand and its nickel,copper and zinc complexes

The new ligand N-(2-acetyl-2-thiazoline)-N′-(2-thiazolidin-2-one) azine (ATHTd) has been synthesized and characterized by X-ray diffraction, elemental analysis, ¹H and ¹³C NMR spectra, elemental analysis, IR and UV–Vis spectra. Also the complexes [NiCl(ATHTd)(H₂O)₂]Cl (1), [Ni(ATHTd)₂](NO₃)₂·H₂O (2), [CuCl₂(ATHTd)] (3) and [ZnCl₂(ATHTd)₂] (4) have been isolated and characterized in the solid state by X-ray diffraction, elemental analysis, IR spectroscopy, UV–Vis–NIR diffuse reflectance, magnetic susceptibility measurements and, in the case of copper(II) complex, EPR spectroscopy. X-ray data indicate that the environment around nickel atoms in 1 and 2 may be described as a distorted octahedral geometry. In 1 the metal ion is coordinated to one chloride ligand, one water molecule and one ATHTd molecule which acts as a tridentate ligand, while in 2 Ni(II) is coordinated to two tridentate ATHTd molecules. With regard to 3, the coordination geometry around copper(II) ion can be considered a distorted square pyramid with the cation coordinated to one tridentate ATHTd ligand and two chloride ligands. Finally, in the case of 4, the Zn(II) is bonded to two ATHTd molecules that acts as a monodentate ligand and two chloride atoms in a distorted tetrahedral geometry. The structure of ATHTd in the complexes presents an amino-2-thiazoline form instead of the iminothiazolidine one observed in free ATHTd. Another significant structural change in complexes, except in 4, is due to the different degree of rotation of the thiazoline rings around the C(1)–C(4) and C(6)–N(3) bonds, which permit the coordination through thiazolinic nitrogen atoms.     

An ion crystal based on MnII-Schiff-base and Keggin polyanions

A new polyoxometalate-templated manganese-Schiff-base compound 1, {[Mn(L)₂]₂[PMo₁₂O₄₀][Cl] · DMF · 2CH₃CN · CH₃OH} _n (where L is 1,4-bis(4-imidazolyl)-2,3-diaza-1,3-butadiene, DMF is N,N-dimethylformamide) has been synthesized by introducing the Metal-Schiff-base into polyoxometalates(POMs) at room temperature, and structurally characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. The result of the single crystal X-ray diffraction suggested that the compound has the packing of the Mn(II)-Schiff-base cation layer and Keggin anion layer.     

Synthesis, infrared spectra, thermal analyses and structural studies of half-sandwich Fe(III)/Fe(II) complex containing pyridine-2,6-dicarboxylate and 1,10-phenanthroline

A new pyridine-2,6-dicarboxylate iron(III)/iron(II) complex [Fe(phen)₃][Fe₂(PDC)₄]·3CH₃OH was synthesized and characterized (where PDC = pyridine-2,6-dicarboxylate, phen = 1,10-phenanthroline) by using elemental analysis, IR spectroscopy and thermal analyses (TGA and DTA). The molecular structure of the complex has been determined by single-crystal X-ray diffraction. The complex is mixed-ligands and the IR spectra display bands characteristic of coordinated mixed-ligand bases. All the IR results are in agreement with the X-ray crystal result. The bond lengths indicate that this complex has [Fe(phen)₃]²⁺ cation where Fe(II) ion is in typical low-spin state, and in counter ions, [Fe(PDC)₂]⁻ are both in high-spin state.     

Zinc(II) and cadmium(II) <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>'-Bis(2-<Emphasis Type="Italic">N</Emphasis>-Tosylaminobenzylidene) diaminodipropyliminates: Syntheses,structures, and photoluminescence properties

Chemical and electrochemical syntheses of the zinc(II) and cadmium(II) complexes with the tetradentate Schiff base (H₂L), the condensation product of 2-N-tosylaminobenzaldehyde with diaminodipropylamine, are carried out. The structures, compositions, and properties of the synthesized metal complexes are studied by elemental analyses, IR spectroscopy, ¹H NMR, UV spectroscopy, X-ray absorption spectroscopy, and quantum-chemical calculations. The structure of the cadmium(II) complex is determined by X-ray diffraction analysis (CIF file CCDC no. 1446393). The cadmium(II) and zinc(II) complexes exhibit luminescence in a CH₂Cl₂ solution in the blue spectral range (λ_PL = 425–428 nm) with the photoluminescence quantum yields ? = 0.20 and 0.75, respectively.     

Synthesis, crystal structure, and DNA interaction and cleavage studies of a novel dinuclear Cu(II) complex with 3-indolylacetic acid

A novel dinuclear Cu(II) complex [Cu₂(C₁₀H₈NO₂)₄(CH₃OH)₂] · 2CH₃OH (I), where C₁₀H₈NO₂ is anion of 3-indolylacetic acid, was synthesized and characterized by elemental analysis, IR spectroscopy, ¹H NMR and single crystal X-ray diffraction. X-ray crystallography shows that Cu²⁺ ion is six-coordinated, embedded in a distorted octahedral center. Each Cu²⁺ ion is coordinated with four carboxylic oxygen atoms from four ligands, one oxygen atom from methanol and the other Cu²⁺ ion. Each ligand links two Cu²⁺ ions through carboxylic oxygen atoms, forming a dinuclear Cu(II) complex. The complex forms a two-dimensional layer structure through N-H??Oⁱ intermolecular hydrogen bonds. The interaction of complex I with calf-thymus DNA (CT-DNA) has been explored by electronic absorption spectroscopy, EB (ethidium bromide) displacement experiments, salt effect, and viscosity measurements. All the results indicate that the complex binds to DNA in a partial intercalative mode. Moreover, agarose gel electrophoresis assay demonstrates that the complex possesses the ability to cleave pBR322 plasmid DNA.     

N,N,N′,N′-Tetrakis(2-hydroxyethyl)ethylenediamine palladium(II) complex as efficient catalyst for the Suzuki/Miyaura reaction in water

A new water soluble palladium(II) complex (2) derived from N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine (edteH₄) (1) was synthesized in high yield and characterized by ¹H, ¹³C, HMQC and COSY NMR spectroscopy. X-ray diffraction studies on a single crystal of 2 confirmed the cis square planar geometry; the edteH₄ ligand (1) is κ² (N,N)-coordinated with four pendant CH₂CH₂OH groups. This new complex [PdCl₂(edteH₄)] (2) and the previously synthesized triethanolamine complex [Pd(OCH₂CH₂N(CH₂CH₂OH)₂)₂] (3) were tested as catalysts for the Suzuki/Miyaura cross-coupling reaction of various aryl bromides with phenylboronic acid in water. Electronically activated aryl bromides, such as 4-bromoacetophenone and 4-bromobenzaldehyde undergo the cross-coupling with extremely high turnover numbers (TON) of up to 1,00,000 without organic solvent.     

Syntheses and characterizations of zinc(II) and copper(II) complexes with reduced Schiff base derived from salicylaldehyde and D,L-selenomethionine

New zinc(II) and copper(II) complexes with a reduced Schiff-base ligand derived from D,L-selenomethionine and salicylaldehyde have been synthesized and characterized by elemental analysis, magnetic susceptibility, IR, and NMR measurements. The single-crystal X-ray structure of the Cu(II) complex reveals that this complex is a carboxylate-bridged dimer of dinuclear copper(II) subunits and all metal centers are five-coordinate with O₄N donor sets in distorted square-pyramidal geometries. The Cu(II) complex consists of a 1-D coordination polymer.     

Synthesis of high surface area NiO nanoparticles through thermal decomposition of mixed ligand Ni(II) Complex, [Ni(binol)(bpy)]∙CH<Subscript>3</Subscript>OH

The present work focuses on the synthesis of high surface area NiO nanoparticles through thermal decomposition of [Ni(binol)(bpy)]?CH₃OH complex as a new precursor. [Ni(binol)(bpy)]?CH₃OH (where binol = racemic-1,1′-bi-2-naphtholate and bpy = 2,2′-bipyridine) was synthesized from reaction of NiCl₂(bpy) with rac-Na₂(binol). The complex was characterized by elemental analysis and spectroscopy techniques of IR, UV-Vis, mass, ¹H and ¹³C NMR. The results revealed that [Ni(binol)(bpy)]?CH₃OH was a paramagnetic tetrahedral complex. The physicochemical properties of the nanoparticles were characterized by various analysis techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and BET specific surface area. The used synthetic rout is facile and economic that makes it suitable for large scale production of pure nickel oxide nanoparticles.     

4-碘吡唑铜配合物的合成、结构及量子化学研究

分别采用水热反应法和溶液培养法, 合成了两个结构新颖的铜配合物[Cu₃(Ipz)₃] (Ipz=4-碘吡唑) (1), [Cu(SO₄)(Ipz)₄]·2H₂O·CH₃OH (2)。通过元素分析、红外光谱、紫外光谱和X-ray单晶衍射方法对其结构进行了表征。晶体结构表明, 配合物1属于正交晶系, Pnma空间群;配合物2属于三斜晶系, P1空间群。配合物1和2的中心金属铜原子的化合价分别是+1和+2价, 金属的配位环境以及配体的配位模式也完全不同。配合物1中金属铜为二配位, 与配体相互连接形成一个闭合的九元环结构;配合物2中金属铜为六配位, 通过配位的硫酸根分子连接形成一条无限的一维链状结构。此外, 对这2个配合物进行了量化计算, 同时还对配合物1进行了荧光光谱分析。     

双核Ni(II)配合物[C17H20N4Ni(H2O)Cl]2Cl2•(CH3OH)的晶体结构及其模板合成新配体

采用“一锅煮”方法, 在金属Ni(II)离子作用下, 以2-乙酰吡啶和1,2-丙二胺物质的量比为2∶1进行反应, 得到了一种新的闭环单Schiff碱N₄四齿配体的配合物[C₁₇H₂₀N₄Ni(H₂O)Cl]₂Cl₂•(CH₃OH). 配合物的晶体结构测定表明, 其配位单元为N桥连的双核配合物, 配位单元间再通过氢键连接成一维链状结构.     

Synthesis,characterization, antifungal,antibacterial and DNA cleavage studies of some heterocyclic Schiff base metal complexes

Co(II), Ni(II), Cu(II) and Zn(II) complexes of the Schiff base derived from indole-3-carboxaldehyde and m-aminobenzoic acid were synthesized and characterized by elemental analysis, molar conductance, IR, UV–Vis, magnetic moment, powder XRD and SEM. The IR results demonstrate the bidentate binding mode of the ligand involving azomethine nitrogen and carboxylato oxygen atoms. The electronic spectral and magnetic moment results indicate that Co(II) and Ni(II) complexes have tetrahedral geometry, while Cu(II) complex is square planar. Powder XRD and SEM indicate the crystalline state and surface morphology studies of the complexes. The antimicrobial activity of the synthesized ligand and its complexes were screened by disc diffusion method. The results show that the metal complexes were found to be more active than the ligand. The nuclease activity of the ligand and its complexes were assayed on CT DNA using gel electrophoresis in the presence of H₂O₂. The Cu(II) complex showed increased nuclease activity in the presence of an oxidant when compared to the ligand and other complexes.     

Synthesis, thermal analysis, and spectroscopic and structural characterizations of zinc(II) complexes with salicylaldehydes

In this study, three new zinc(II) complexes with 5-substituted salicylaldehyde ligands (X-saloH) (X = 5-chloro, 5-nitro and 5-methyl) with the general formula [Zn(X-salo)₂(CH₃OH)n], (n = 0 or 2) were synthesized. An octahedral geometry was found for both the complexes [Zn(5-NO₂-salo)₂(CH₃OH)₂] and [Zn(5-Cl-salo)₂(CH₃OH)₂] by single-crystal X-ray diffraction analysis. These complexes were characterized also by spectroscopy (IR and ¹H-NMR). Simultaneous TG/DTG–DTA techniques were used to analyze their thermal behavior under inert atmosphere, with particular attention to determine their thermal degradation pathways, which was found to be a multi-step decomposition accompanied by the release of the ligand molecules. Finally, the kinetic analysis of the decomposition processes was performed by applying both the isoconversional Ozawa–Flynn–Wall (OFW) and the Kissinger–Akahira–Sunose (KAS) methods.     

Crystal structure,electrochemical, and antibacterial activity of the sodium complex formed by o-vanillin salicylhydrazone

The mononuclear sodium(I) complex [NaL(HL)] (1) [where HL is (OH)C₆H₄–CO–HN–N=CC₆H₃(OMe)(OH) synthesized by condensation of o-vanillin and salicyloylhydrazine] has been prepared and characterized by IR, elemental analysis, single crystal X-ray diffraction, and cyclic voltammetry. Single crystal X-ray diffraction analysis reveals that NaL(HL) is a neutral complex. Each six-coordinate Na(I) in the unit is linked through O bridges forming a ladder-like arrangement of the 1-D Na(I) double chain. The oxidation–reduction processes have been determined in CH₃CN by cyclic voltammetry. The complex displayed two quasi-reversible reduction couples and one oxidation response between +1.0 and ?0.6 V. The trend in the half wave potentials reflects the electronic nature of the hydrazone ligand. The antibacterial activity results show that the complex possesses strong inhibition activity against Staphyloccus aureus and Bacillus subtilis.     

Synthesis,spectral, thermal,potentiometric and antimicrobial studies of transition metal complexes of tridentate ligand

A series of metal complexes of Cu(II), Ni(II), Co(II), Fe(III) and Mn(II) have been synthesized with newly synthesized biologically active tridentate ligand. The ligand was synthesized by condensation of dehydroacetic acid (3-acetyl-6-methyl-(2H) pyran-2,4(3H)-dione or DHA), o-phenylene diamine and fluoro benzaldehyde and characterized by elemental analysis, molar conductivity, magnetic susceptibility, thermal analysis, X-ray diffraction, IR, ¹H-NMR, UV–Vis spectroscopy and mass spectra. From the analytical data, the stoichiometry of the complexes was found to be 1:2 (metal:ligand) with octahedral geometry. The molar conductance values suggest the non-electrolyte nature of metal complexes. The IR spectral data suggest that the ligand behaves as a dibasic tridentate ligand with ONN donor atoms sequence towards central metal ion. Thermal behaviour (TG/DTA) and kinetic parameters calculated by the Coats–Redfern and Horowitz–Metzger method suggest more ordered activated state in complex formation. To investigate the relationship between stability constants of metal complexes and antimicrobial activity, the dissociation constants of Schiff bases and stability constants of their binary metal complexes have been determined potentiometrically in THF–water (60:40%) solution at 25 ± 1 °C and at 0.1 M NaClO₄ ionic strength. The potentiometric study suggests 1:1 and 1:2 complexation. Antibacterial and antifungal activities in vitro were performed against Staphylococcus aureus, Escherichia coli and Aspergillus niger, Trichoderma, respectively. The stability constants of the metal complexes were calculated by the Irving–Rosotti method. A relation between the stability constant and antimicrobial activity of complexes has been discussed. It is observed that the activity enhances upon complexation and the order of antifungal activity is in accordance with stability order of metal ions.     

Synthesis,characterization and antibacterial activity of some new complexes of Cu(II), Ni(II), VO(II), Mn(II) with Schiff base derived from 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one

Coordination compounds of Cu(II), VO(II), Ni(II), and Mn(II) with the Schiff base obtained through the condensation of 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one with 3-formyl-6-methyl-chromone were synthesized. The characterization of the newly formed compounds was done by ¹H NMR, UV–Vis, IR, ESR spectroscopy, elemental analysis and molar electric conductibility. The crystal structure of 1-phenyl-2,3-dimethyl-4-(N-3-formyl-6-methyl-chromone)-3-pyrazolin-5-one (HL) has been determined by X-ray diffraction studies, as well as the one of its copper(II) complex [CuL(OAc)]·CH₃OH which contains an anionic ligand and an acetate in the coordination sphere of the metal. The single crystal X-ray structure for (HL) was analyzed for its various weak H-bonding and dimeric association.     

Synthesis,characterization and antiprotozoal studies of some metal complexes of antimalarial drugs

Metal complexes of the antimalarials trimethoprim (TMP), chloroquine (CQ), and pyrimethamine (pyrm) formulated as [Mn(TMP)Cl₂(CH₃OH)], [Co(TMP)₂Cl₂(CH₃OH)], [Pt(CQ)₂Cl₂] and [Cu(pyrm)₂(CH₃COO)₂] have been synthesized and characterized by elemental analysis, magnetic susceptibility measurements, IR and UV-Vis spectroscopy. The IR and electronic spectra are consistent with the proposed geometry for the complexes. The Mn(II) and Pt(II) complexes are four coordinate while the Cu(II) and Co(II) have octahedral geometry. The complexes were tested for in vitro activity against cultures of Trypanosoma cruzi, L. donovani, T. b. rhodesiense and the resistant strains of Plasmodium falciparum to determine their antiprotozoal activities and for their cytotoxicity with L-6 cells. The Pt(II) complex of chloroquine showed enhanced activity against the resistant strain of Plasmodium falciparum.     

Synthesis and spectral studies on palladium and platinum complexes with mono- and bidentate N-donor organic ligands and their interaction with calf thymus DNA in solution

Palladium(II) and platinum(II) complexes of the types PdLX₂, PdL₂X₂, PtL₂X₂ and the Pt(IV) complexes PtLX₂Y₂, PtL₂X₂Y′₂ (where L = mono- or bidentate organic ligand containing nitrogen donor atoms; X = Cl or Br; Y = Br and Y′ = OH) have been synthesized and characterized by elemental analysis, IR and X-ray photoelectron spectral data. The Pd 3d_5/2 binding energies indicate that the 8-aminoquinoline ligand is a better electron donor to the metal than other ligands studied. The Cl 2p_3/2 binding energies in the square planar pd(II) complexes are observed in the range 198.0–199.56 eV. The ν(PdCl) vibrations (ca 340 and 320 cm^?1) corresponding to two cis-Cl ligands were observed in the IR spectra. Binding through probably N-7 of the guanine residue and the phosphate oxygen in a chelate form is implied from UV difference spectral data.     

Studies on Co(II) and Cu(II) complexes of a ligand derived from 1,3-phenylenediamine and 5-bromosalicylaldehyde synthesis, characterisation, thermal properties and use as new precursors for preparation cobalt and copper oxide nano-particles

A symmetric tetradentate Schiff base ligand, N,N′-bis(5-bromosalicylaldehyde)-1,3-phenylenediamine [(Brsal)₂-1,3-phen) and its Cu(II) and Co(II) complexes with general formula M₂((Brsal)₂-1,3-phen)₂, where M=Co (1) and Cu (2)], have been synthesized and characterized by elemental analyses and FTIR spectroscopy. In addition, Schiff base ligand has been characterized by ¹HNMR spectroscopy. Thermogravimetric analysis of the ligand and its metal complexes reveals their thermal stability and decomposition pattern.