Synthesis,characterization, and biological studies of lanthanide complexes with 2,6-pyridine dicarboxylic acid and α-picolinic acid

Four new solid ternary complexes of lanthanide with 2,6-pyridine dicarboxylic acid and α-picolinic acid [Ln(DPA)(L^α)(H₂O)] · 2H₂O (Ln = La³⁺, Ce³⁺, Eu³⁺, or Gd³⁺; DPA = 2,6-pyridine dicarboxylic acid; HL^α = α-picolinic acid) have been synthesized and characterized by elemental analysis, molar conductance, FT-IR, UV–Vis, and TG–DTA. The antibacterial activities indicate that all the complexes exhibit antibacterial ability against Escherichia coli and Staphylococcus aureus with broad antimicrobial spectra. The anticancer activity of the La complex against K562 tumor cell in vitro is measured using methyl thiazolyl tetrazolium (MTT) colorimetry and flow cytometry. The La complex can induce K562 tumor cell apoptosis, presenting the best apoptosis effect by acting on the S period after inducing K562 tumor cell for 72 h.     

Synthesis,characterization, catalytic and biological activity of some bimetallic selenocyanate Lewis acid derivatives of N,N ′- bis (2-chlorobenzylidene)ethylenediamine

Complexes of MM′(SeCN)₄, (M = Co²⁺, Ni²⁺; M′ = Cd²⁺, Zn²⁺) with the Schiff base, N,N′-bis(2-chlorobenzylidene)ethylenediamine have been synthesized and characterized by elemental analysis, molar conductance, magnetic moment, FTIR, ¹H-NMR, ¹³C{¹H}-NMR and electronic spectroscopy. The catalytic activity of these complexes for hydrolysis of benzonitrile has been investigated. The complexes have also been investigated for antibacterial activity against Escherichia Coli and found to exhibit good growth inhibiton.     

Synthesis and characterization of a novel Mn(III)-(γ-diketone) complex with catalytic and antifungal activity

Abstract

A novel Mn(III) complex with γ-diketone having general formula [Mn(hdo)₃], where hdo?=?hexane-2,5-dione ligand, has been synthesized and characterized using UV–vis, FT-IR, ESI-mass and EPR spectra, elemental analysis, powder X-ray diffraction, SEM, and magnetic susceptibility measurements. The X-ray diffraction studies reveal that it has monoclinic lattice system with C₂/C space group and the unit cell dimensions are a?=?9.92245 Å, b?=?10.50696 Å, and c?=?9.80835 Å. The particle size of this complex has been found to be 32.1?nm. The complex was evaluated for its antifungal activity against Aspergillus flavus, Aspergillus niger, and Aspergillus terreus fungal species. The results indicate that the minimum inhibitory concentration of the synthesized complex was 8?ppm for A. niger while for A. flavus and A. terreus it was 6?ppm. β-Diketone Mn(III) complexes inhibit the fungal growth only partially. This communication is the first report of transformation of a keto-group to an ester group catalyzed by a metal complex.     

Synthesis,characterization and antibacterial activity of a curcumin–silver(I) complex

The current study reports the synthesis of a curcumin–silver(I) complex and its preliminary tests against four bacterial strains viz. Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Bacillus cereus using agar well diffusion method. The results were compared with curcumin by testing it in parallel with the sample. Curcumin showed zones of inhibition against all tested strains of bacteria. Among all bacterial strains, S. aureus was the most sensitive to curcumin with zone of inhibition of 12.2 mm. However, the curcumin–Ag(I) complex did not show the expected enhanced activity against all bacteria. This is perhaps due to the replacement of curcumin phenolic protons by silver ions which might have suppressed the antibacterial property of curcumin. The current research findings suggest that while synthesizing curcumin–metal complexes, the phenolic heads may either be left unaltered or need to be replaced by better substituents than hydroxy groups. Based on the current findings, biologically enhanced models have been provided as future recommendations.     

Synthesis,physicochemical characterization,and biological activity of nanocomplexes of iron(III) of 3(2′-hydroxyphenyl)-5-(4-substituted phenyl) pyrazolines and dithiophosphoric acid

Complexes of iron(III) with dithiophosphoric acid and 3(2′-hydroxy phenyl)-5-(4-substituted phenyl) pyrazolines, [Fe(C₆O₁₄O₂PS₂)₂(C₁₅H₁₂N₂OX)], and [Fe(C₆O₁₄O₂PS₂)(C₁₅H₁₂N₂OX)₂], where (C₆O₁₄O₂PS₂H) = dithiophosphoric acid, (C₁₅H₁₃N₂OX) = deprotonated 3(2′-hydroxy phenyl)-5-(4-substituted phenyl)pyrazolines (X?=?H, CH₃, OCH₃, Cl), have been synthesized. These complexes have been physicochemically characterized by elemental analysis (C, H, N, S, Cl, and Fe), magnetic moment data, thermogravimetric analysis, molar conductance, cyclic voltammetry, and spectral analysis (UV–visible, IR, and Fast atom bombardment mass spectrometry). Scanning electron microscopy, TEM, and PXRD have been carried out for powdered samples, which show nanometric particles of these derivatives. Antibacterial and antifungal potential of free pyrazoline and iron(III) complexes have been evaluated.     

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 characterization of organotitanium substituted heteropolytungstosilicates and their biological activity

Tris-, di-(organotitanium) substituted tungstosilicates α、β-[(CpTi)3(SiW9O37)]7- and γ-[(Cp-Ti)2(SiW10O38)]6- were prepared by the reaction of Cp2TiCl2 (Cp = η5-C5H5) with α、β-SiW9O349- (noted α、β-SiW9), γ-SiWO368- (noted γ-SiW10) . The products were characterized by means of elemental analysis, IR, 1H NMR, 183W NMR and polarography. 183W NMR spectra of the complexes support the stoichiometry of the new heteropolyanions and the probable retention of the A-XWg or γ-SiW10 units. And the organotitanium substituted compounds showed promising in vitro antitumor activity in two of human tumor cell lines.     

Synthesis, characterization, antitumor activity of nickel(Ⅱ) and cobalt (Ⅱ) complexes of 2,2''''-diamino-4,4''''-bithiazole and their interaction with dGMP

New complexes,of bis(2,2'-diamino-4,4'-bithiazole)sulfate nickel(Ⅱ) and bis(2,2'-diami-no-4,4'-bithiazole)sulfate cobalt(Ⅱ),have been prepared.The complexes were characterized by infrared and UV-Vis spectroscopy,1H NMR,elemental analyses and molar conductivity.The effect of these complexes on the DNA synthesis of sarcoma 180 cells has been studied by the technique of isotopic liquid scintillation.The results indicated that complexes show ability to inhibit DNA synthesis of the tumor cells.In order to provide a molecular basis for understanding the biological effects,the probe,[trana-en2Os(η2-H2)](CF3SO3)2 (en,ethylenediamine) as a monitor was first used to explore interaction of the complexes with 2'-deoxyguanosine-5'-monophosphate (dGMP).     

Synthesis, characterization, and electron transfer reaction of some surfactant–cobalt(III) complex ions

Abstract  

The surfactant complex ion cis-[Co(tmd)₂(C₁₂H₂₅NH₂)₂]³⁺ (tmd = 1,3-propanediamine, C₁₂H₂₅NH₂ = dodecylamine) has been synthesized and characterized by elemental analysis and spectral data. In addition we have determined the critical micelle concentration of the surfactant–cobalt(III) complex and studied the kinetics and mechanism of the complex with ferrocyanide anion. The reaction is found to be second order, and the second-order rate constant increases with increasing initial concentration of the surfactant–cobalt(III) complex due to the presence of self-micelles formed by the complex itself. The thermodynamic parameters were determined. The results have been analyzed.     

Synthesis,characterization, molecular and supramolecular structures of nickel(II) complexes derived from α-diketone and α-ketoaldehyde bisaroylhydrazones

A new series of nickel(II) complexes derived from symmetrical diacetyl bisaroylhydrazones [Ni(L¹-R)] and unsymmetric phenylglyoxal bisaroylhydrazones [Ni(L²-R)] have been prepared and characterized. X-ray crystal and molecular structures of [Ni(L¹-H)], [Ni(L¹-pCH₃O)] and [Ni(L¹-pNO₂)] have been determined. In these complexes, the Ni(II) is in a distorted square planar environment and the aroylhydrazone acts as dinegative tetradentate ligand forming a 5,5,5-tricyclic chelate ring. Reaction of [Ni(L¹-R)] with aqueous ammonia afforded the paramagnetic five coordinate [Ni(L¹-R)(NH₃)] while [Ni(L²-R)] gave the diamagnetic square planar [Ni(L²-R)(NH₃)] complexes. Reaction of [Ni(L¹-R)] complexes with imidazole gave the corresponding paramagnetic octahedral bis(imidazole) adducts. X-ray structures of both [Ni(L¹-H)(HIm)₂] and [Ni(L¹-pNO₂)(HIm)₂] suggest a distorted octahedral structure where the bisaroylhydrazone occupies the basal plane while the two imidazoles occupy the axial sites. The molecular units are associated together forming triple stranded helical chains. With imidazole the [Ni(L²-R)] series gave the corresponding diamagnetic mono(imidazole) [Ni(L²-R)(HIm)] complexes, The X-ray structure of {Ni(L²-pCH₃)(HIm)] suggest square planar arrangement around the Ni(II) where the bisaroylhydrazone acts as dinegative NNO tridentate ligand forming with the Ni(II) a 5,6-bicyclic chelate ring the fourth coordination site is occupied by imidazole nitrogen.     

Synthesis and biological activity of some 8α-analogs of steroidal estrogens

8α-Analogs of steroidal estrogens containing a methyl group on C¹ or an oxo group on C⁶ were synthesized with a view to obtain compounds exhibiting selective biological activity, and their steric structure was studied. As shown with 1,3-O-dimethyl-8α-estrone as an example, such compounds in solution can exist as two conformers, whereas the oxo group on C⁶ almost does not affect conformation of the modified derivative as compared to the parent structure. Some newly synthesized compounds exhibited hypocholesterolemic activity in combination with reduced uterotropic effect, which is important for the design of drugs for the treatment of atherosclerosis. 6-Oxo-8α-analogs showed osteoprotective activity, so that introduction of an oxo group into the 6-position is promising from the viewpoint of hormone replacement therapy.     

Synthesis and biological activity of α-alkylacrolein dimers and their derivatives

Dimers of methacrolein and α-ethylacrolein have been obtained and undergo a Cannizzaro reaction to the corresponding pyran alcohols and sodium salts of pyran acids. Their bacteriostatic, bactericidal, and fungicidal properties have been studied. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1639–1644, November, 2008.     

Synthesis and crystal structure of dinuclear nickel (Ⅱ) complex

The crystal structure of Ni(Ⅱ) complex with 3-hydroxyl-1, 5-diazacycloheptane-N, N'-diacetate was determined by X-ray diffraction method. Crystal data for Ni2 (C9H14N2O5)2·2H2O: monoclinic, space group P21/n, a = 1.1717(5), b = 0.9794(3), c = 1.2971(2) nm, β= 96.62(3), V= 1.4786(7) nm3, Dc = 1.377 g/cm3, Z = 2,μ=13.321 cm-1 (Mo-Kα), F(000)=640. The final R and Rw are 0.075 and 0.089 respectively. The Ni(Ⅱ) ion forms 2:2 complex with ligand. Two ligands are bridged by two Ni(Ⅱ) atoms which are bridged by two O atoms. Every Ni(Ⅱ) is coordinated by two N atoms and four 0 atoms. The coordination polyhedron of the Ni(Ⅱ) ion is a distorted octahedron.     

Synthesis and characterization of α-, β- and γ-cyclodextrin-nicotinamide

Abstract

α-, β- and γ-cyclodextrin-nicotinamide (α-, β- and γ-CDNA) were synthesized as NADH coenzyme models, and the binding abilities were investigated. CDNA binds a negatively charged guest stronger than unmodified cyclodextrin because of the electrostatic interaction between the nicotinamide residue and the guest molecule. Different binding abilities were measured and were dependent on cavity size.     

Synthesis,X-ray crystal structure,electrochemical and antibacterial activity of a silver(I) complex with α-bromo-cinnamaldehyde salicylhydrazone

The mononuclear silver(I) complex [AgL(HL)·DMF] (I) (HL = C₆H₁₃O₂N₂Br) has been prepared and characterized by physicochemical and spectroscopic methods, single crystal X-ray diffraction, cyclic voltammetry, and antibacterial activity tests. The complex crystallized in the triclinic system, and each Ag(I) is six-coordinate with a distorted octahedral geometry. The ligands chelate the metal center with N, O, and Br atoms from two different Schiff base ligands. O–H···O intermolecular hydrogen bonds connect adjacent complex molecules to form zigzag one-dimensional linear chains along the b axis. Cyclic voltammetry showed that the complex displays an irreversible reduction process at −0.41 V. The data from antibacterial activity tests indicate that the complex inhibits the growth of Staphyloccus aureus and Bacillus subtilis Cohn.     

Synthesis,crystal structures and magnetic properties of two new nickel(II) complexes with α-amino acid Schiff base

Two nickel(II) complexes [Ni(napgly)(MeOH)] _n (1) and [Ni(napphe)(H₂O)₂(MeOH)] · H₂O (2), where the tridentate Schiff-base ligands H₂napgly and H₂napphe are condensed from 2-hydroxyl-1-naphthaldehyde with glycine and L-phenylalanine, respectively, were prepared and structurally characterized. In 1, two inversion-related Ni(II) ions were bridged by two O atoms from the phenolate groups of two napgly anions, forming a centrosymmetric dimeric unit which was further linked by carboxylate groups to give a two-dimensional network. Magnetic susceptibility studies performed on the complex revealed anti-ferromagnetic coupling between the metal centers. In 2, the crystal structures of the complex displayed a distorted octahedral coordination geometry in which the ONO-donor Schiff base was bonded to the metal. Intermolecular H-bonds linked the compound into a 2-D layer structure.     

Synthesis and characterization of α,ω-dichloro-polymethylphenylsilane

The synthesis of a functional polysilane, α,ω-dichloro-polymethylphenylsilane (α,ω-dichloro-PMPS), based on the Wurtz-type reductive coupling, has been considered. A study of some reaction parameters shows that both yield and molecular weight distribution of α,ω-dichloro-PMPS can be greatly influenced by the work-up conditions, reaction time, monomer concentration and temperature during the initiation of the polymerization. By varying the synthesis conditions, different ratios of high and low molecular weight fractions were obtained. Samples of different molecular weight were isolated by fractional precipitation of the crude polymers. The chlorine-end functionalization was confirmed by ²⁹Si NMR spectroscopy and the concentration of end-groups was quantitatively determined by elemental analysis of chlorine.     

Synthesis,characterization, and crystal structure of one zinc(II) complex with 4-Hydroxypyridine-2,6-Dicarboxylic acid and 4,4′-bipyridine

A new zinc(II) coordination polymer, {[Zn(HCAM)(4,4′-Bipy)_0.5] · H₂O} _n (I) (H₃CAM = 4-hydroxypyridine-2,6-dicarboxylic acid; 4,4′-Bipy = 4,4′-bipyridine), has been synthesized by hydrothermal reaction of Zn(OAc)₂, H₃CAM and 4,4′-Bipy. It has been structurally characterized by element analysis, IR-spectra. X-ray single-crystal analysis was carried out for I (CIF file CCDC no. 974199), which crystallizes in the orthorhombic system, space group Pbca. The single X-ray diffraction studies reveal that I shows a new 2D wave-like plane with 3-connected net. Furthermore, the thermal stability of compound I was studied.