Vol 86, No 4 (2016)
- Year: 2016
- Articles: 40
- URL: https://journals.rcsi.science/1070-3632/issue/view/13357
Article
Formation of binary salts in the system LiCl–CsCl–H2O
Abstract
In the ternary system LiCl–CsCl–H2O the binary salt LiCl·2CsCl·4H2O was formed. Its structure was proved by the X-ray structural analysis. The binary compound formed in the aqueous solution by the structurally-forced insertion mechanism.
Solubility of d-element salts in organic and aqueous–organic solvents: II. Effect of halocomplex formation on solubility of cobalt bromide and chloride and nickel chloride
Abstract
Solubility of salts in the systems MCl2–H2O–Solv (M = Co, Ni) and CoBr2–H2O–Solv (Solv = dimethyl sulfoxide, dimethyl formamide, and dimethyl acetamide) at 25°C was measured experimentally. Dominating species of cobalt and nickel halides existing in various concentration regions were identified by analysis of electron absorption spectra. It was shown that the major factor defining solubility is the interaction of halocomplexes of metal ions with solvent molecules.
Solid-state synthesis of nanocrystalline strontium zirconate assisted by mechanical activation
Abstract
Nanocrystalline SrZrO3 has been synthesized by a solid-state procedure using mechanical preactivation of a strontium carbonate–zirconia mixture in an AGO-2 centrifugal planetary mill. The effect of mechanical activation of the reactant mixture on the processes occurring during its subsequent heating has been studied by thermal analysis. The resulting strontium zirconate has been characterized by X-ray diffraction and by scanning and transmission electron microscopy.
Structure and photocatalytic properties of materials based on titanium dioxide and silver nanoparticles
Abstract
Phase composition and structure of mesostructured materials, titanium dioxide and titanium dioxide modified with silver nanoparticles, have been studied by X-ray diffraction analysis. Introduction of Ag(I) ions into the initial composition and variation of the annealing temperature over the 500–950°C range allows controlling the anatase to rutile crystal phase ratio in the samples. The photocatalytic activity of TiO2 and TiO2/Ag samples has been demonstrated using the methyl orange degradation reaction. The catalytic properties of the materials have been found to depend on the anatase to rutile phase ratio and on the presence of silver nanoparticles.
Colloid and nanosized catalysts in organic synthesis: XIV. Reductive amination and amidation of carbonitriles catalyzed by nickel nanoparticles
Abstract
Hydrogenation of carbonitriles catalyzed by nickel nanoparticles in the presence of primary amines led to the predominant formation of unsymmetrical secondary amines. In the presence of secondary amines hydrogenation of nitrites provided enamines as main products. Hydrogenation of nitriles in the presence of formamide or acetamide afforded formyl or acetyl derivatives of primary amines.
Structure of aminonitrones and electronic effect of substituents on their acid-base properties
Abstract
A series of para-substituted aromatic aminonitrones p-RC6H4C(NH2)=N+(Me)O– (R = NMe2, H, Br, Cl, CF3) have been prepared. Acidity constants of the conjugate acids RC6H4C(NH2)N+(Me)OH at 25°C in a EtOH–H2O mixture (5: 95) have been determined by potentiometric titration. A linear correlation between log (kR/kH) and σpara values has been revealed, and a ρ298(σpara) parameter has been determined as of 0.635.
Approach to preparative synthesis of ortho-(1-methylbut-2-en-1-yl)anilines, precursors of new cytotoxic heterocycles
Abstract
The reaction of aromatic Claisen rearrangement of N-(1-methylbut-2-en-1-yl)anilines in the presence of p-toluenesulfonic acid was investigated. N-Tosyl-2-(1-iodoethyl)-3-methylindoline derivatives were obtained; one of them exhibited a cytotoxic activity.
Study of acid-base properties of morin by tristimulus colorimetry
Abstract
Acid-base properties of morin in aqueous solutions have been studied by means of chemical tristimulus colorimetry, and the ionization constants have been determined. The pK values have been assigned to the corresponding functional groups, and their dissociation scheme has been suggested. Diagram of distribution of ionic and molecular forms of morin at pH 1–13 has been constructed. Spectral parameters of equilibrium acid-base forms of morin have been determined.
Synthesis and reactivity of maleopimaric acid N-aryl(aralkyl)imidoamides
Abstract
A method of synthesis of maleopimaric acid N-aryl(aralkyl)imidoamides by reaction of the corresponding aromatic amides of maleopimaric acid and amines in p-xylene at reflux was developed. Thermal stability of the synthesized compounds was evaluated by derivatography.
New method of preparation of carboxy-protected amino acid conjugates of glycyrrhizinic acid
Abstract
A method for preparation of carboxy-protected amino acid conjugates of glycyrrhizinic acid with the use of N-hydroxybenzotriazole, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and methyl esters of L-amino acids (phenylalanine, tyrosine, leucine, isoleucine, and methionine) in 85–90% yield was developed. The structure of the prepared compounds was confirmed by IR and 13C NMR spectra.
The effect of functional substitution on thermal stability of pyridinylporphyrins under argon atmosphere
Abstract
The data on thermal stability under argon atmosphere of a series of porphyrin ligands containing meso- and β-positioned electron-donor (Me, Et, or Ph) groups as well as electron-acceptor pyridinyl substituents differing in the heteroatom location are presented. Thermogravimetric analysis and electron absorption spectroscopy studies have shown that pyridinylporphyrins are thermally stable at heating to 360–500°С depending on the functional substitution in the molecule.
Synthesis, spectral luminescent properties, and photostability of monoiodo- and dibromo-substituted BF2-dipyrrinates
Abstract
4-Iodo-, 4,4′-, and 5,5′-dibromo-substituted BF2-dipyrrinates (BODIPY) have been prepared, and their spectral luminescent properties and photostability have been studied. It has been shown that the introduction of iodine and bromine atoms in the molecule structure results in build-up of the BODIPY phosphorescence and decrease in their fluorescence quantum yield. Basing on the obtained data, the prepared dipyrrinates can be recommended for development of fluorescent sensors for medical and technical applications.
Synthesis and association in dichloromethane solution of low-symmetry phenoxy(fluoro)-substituted nickel phthalocyaninates
Abstract
Cross-condensation of 4,5-diphenoxyphthalonitrile (component A) with tetrafluorophthalonitrile (component B) in the presence of nickel(II) acetate has yielded the low-symmetry nickel phthalocyaninates of the A3B, ABAB, and AABB types. Their spectral properties have been studied. It has been demonstrated that even at the concentration as low as (6.0–8.0) × 10–7 mol/L the examined complexes exist in the associated form in the dichloromethane solution.
Adducts of tetracoordinate cobalt(II) complexes and 1-(pyridin-2-yl)methanimine: Computational search for valence tautomeric systems
Abstract
A density functional theory method [B3LYP*/6-311++G(d,p)] was used to study mixed-ligand adducts of tetracoordinate cobalt(II) complexes and 1-(pyridin-2-yl)methanimines. Stability of the adducts with respect to dissociation into the initial components and the possibility of intramolecular electron transfer were explored. The calculated energy characteristics of the adduct of Co(II) bisacetylacetonate with a redox-active ligand functionalized by cyano groups suggest the possibility of valence tautomerism in this compound.
Synthesis of 2-(diphenylphosphoryl)phenyl ethers of ethylene glycols and structure of their sodium and potassium complexes
Abstract
Phase-transfer catalysis and template assembly on sodium and cesium cations were used to prepare 2-(diphenylphosphoryl)phenyl ethers of ethylene glycols Ln with varied number of polyether units (n = 3–8). Previously unknown dinitro and disulfo derivatives of 2-(diphenylphosphoryl)phenyl ethers of di- and triethylene glycols were synthesized. Complexes [NaL4]NCS·C6H6, [NaL4]ClO4, [KL5]NCS, and [KL5]ReO4 were synthesized, and their crystal structure was studied. Structure–stability constant correlations were found for alkali metal complexes with phosphoryl podands Ln and isodentate crown ethers.
Synthesis and structure of enaminoketones of pyrazole containing 2-thione(selenone)benzimidazolyl fragments and their zinc and cadmium complexes
Abstract
New ligand systems based on 4-formyl-5-hydroxypyrazole and 1-aminobenzimidazole derivatives are synthesized. The obtained enamines and their Zn2+ and Cd2+ metal complexes of composition ML2 were investigated using the IR, heteronuclear (1H, 13C, 15N, 77Se, 113Cd) and two-dimensional NMR spectroscopy (COSY, HSQC, HMBC). The data of physicochemical investigations and quantum-chemical calculations showed that the ligands exist in the ketoamine tautomeric form. Quantum-chemical simulation of Zn(II) and Cd(II) complexes showed that the zinc complexes adopt the pseudo-tetrahedral and the cadmium complexes pseudo-octahedral configuration.
New methacrylate-containing derivatives of hydroxyethyl starch
Abstract
Modification of hydroxyethyl starch with glycidyl methacrylate in dimethylsulfoxide medium has resulted in the formation of the derivatives containing double C=C bonds capable of producing biocompatible hydrogels via the free-radical cross-linking. Structure of the glycidyl methacrylate derivatives has been elucidated by means of IR, UV, and NMR spectroscopy. Branching of the hydroxyethyl starch chains in the course of the interaction with glycidyl methacrylate has been observed and interpreted; the branching density has been determined. The influence of the substitution degree of the glycidyl methacrylate derivatives of hydroxyethyl starch on its melting point has been demonstrated.
Nafion-based composite solid electrolytes containing carbon nanotubes
Abstract
Nafion-based composite solid electrolytes containing multiwalled carbon nanotubes have been studied by impedance spectroscopy. The effect of carbon nanotube morphology on the proton conductivity of the composites has been estimated at low relative humidity. Surface modification of carbon nanotubes with acidic groups increases the proton conductivity.
Nafion-based composite solid electrolytes containing water-soluble fullerene C60 derivatives
Abstract
Nafion-based composite solid polyelectrolytes containing fullerene C60 and its water-soluble derivatives fullerenol-C60 and tris-malonate-C60 were studied by the impedance spectroscopy method. It was found that introduction of these dopants in Nafion leads to a substantial increase in proton conductivity of the composites in the region of low relative humidity. The reasons for the influence of dopants on proton conductivity of composites were discussed.
Glycine adsorption on a mercury electrode modified by neodymium
Abstract
Ranges of neodymium reduction potentials in aqueous solutions of potassium chloride at pH = 2 and in solutions containing glycine were determined by differential pulse polarography. The glycine complex with neodymium is not formed in the range of the amino acid concentration 0.001–0.12 M. Glycine adsorption on a mercury electrode and on an electrode modified with neodymium was studied by the cyclic voltammetry method.
Transition metal chelates: Synthesis, physicochemical, thermal, and biological studies
Abstract
The transition metal complex of Mn(II), Co(II), Ni(II), Cu(II), Ti(III), Cr(III), Fe(III), Zr(IV), and UO2(VI) ion with a Schiff’s base ligand derived from 2-hydroxy-[2-oxo-1,2-dihydro-3H-indol-3-ylidene]-benzohydrazide have been prepared. The complexes have been characterized by elemental analysis data, IR and electronic absorption spectra, magnetic moments, and thermogravimetric analysis data. The complexes of the 1: 1 metal-to-ligand stoichiometry have been formed. The physico-chemical data have suggested the octahedral geometry for all the complexes except for Cu(II); the Cu(II) complex has been square planar. Thermal analysis data of the ligand and its complexes have been analyzed, and the kinetic parameters have been determined using the Horowitz–Metzger method. According to the solid-state electrical conductivity measurements, the ligand and its complexes are semiconducting in nature. The antimicrobial activity of the ligand and the complexes towards E. coli, S. typhi, P. aeruginosa, and S. aureus has been tested by the disc diffusion method.
Microwave-assisted synthesis of 1-{2-[(1-benzyl-1H-1,2,3-triazol-4-yl)methoxy]phenyl}-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones and their antimicrobial activity
Abstract
A series of new (E)-1-{2-[(1-benzyl-1H-1,2,3-triazol-4-yl)methoxy]phenyl}-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones (3a–3i) has been synthesized via copper-catalyzed 1,3-dipolar azide-alkyne cycloaddition reaction (CuAAC) of benzyl azide with substituted (E)-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)-1-[2-(prop-2-ynyloxy)phenyl]prop-2-en-1-ones (2a–2i). The synthesized compounds have been characterized by their IR, lH, 13C NMR spectra, and mass spectroscopy data. All the compounds have been screened for antimicrobial activity.
Preparation of graphene oxide and its application in Ni2+ removal
Abstract
Graphene oxide (GO) has been prepared by the modified Hummers method using graphite as starting material. The product was studied by the X-ray diffraction (XRD), Raman spectroscopic, transmission electron microscopic (TEM), and scanning electron microscopic (SEM) analyses. Adsorption capacity of GO for heavy metal ions was studied for the example of the Ni2+ ions and the adsorption kinetics and adsorption isotherm were determined. It was shown that the adsorption equilibrium curves are adequately described by the Langmuir equation.
Synthesis of some novel S-alkylated and S-glycosylated hydantoin derivatives containing pyrene moiety
Abstract
3-Aryl-5-[(Z)-pyrenylmethylene]-2-alkylthiohydantoins and 3-Aryl-5-[(Z)-pyrenylmethylene]-2-(D-glycosyl)-2-thiohydantoins functionalized with different aromatic and glycoside substituents have been synthesized by the reaction of (Z)-3-(4-methoxyphenyl)-5-[(pyren-8-yl)methylene]-2-thiohydantoin with alkyl halides, cyclic and acyclic nucleosides via various routes with moderate to good yields and characterized by 1H, 13C NMR and mass spectra and elemental analysis
Multiple hydrogen bonds-mediated formation of supramolecular polysiloxanes based on oligoamide duplexes
Abstract
Formation of supramolecular polysiloxane polymers was studied by using oligoamide strands 1a, 2a, and 3a bearing multiple hydrogen bonds as association units. According to SEM and TEM studies one polymeric strand associated into supramolecular spherical assemblies via duplex formation. The results demonstrated the effect of such complementary oligoamides upon constructing main-chain supramolecular polymers.
Microwave assisted selective synthesis of (E)-1-(4-Chloro-7-hydroxy-2-aryl-2H-chromen-6-yl)-3-arylprop-2-en-1-ones and their antimicrobial activity
Abstract
A series of new (E)-1-(4-chloro-7-hydroxy-2-aryl-2H-chromen-6-yl)-3-arylprop-2-en-1-ones (2a–2f) have been synthesized by selective mono cyclization of 4,6-dicinnamoyl resorcinols (1a–1f) using Vilsmeier–Haack reagent under conventional heating and microwave irradiation. The structures of the synthesized compounds have been elucidated by elemental analysis, IR, 1H NMR, 13C NMR and Mass spectral data. The synthesized compounds were tested in vitro for antimicrobial activity.
One-pot synthesis of xanthene derivatives catalyzed by Fe(III) tetranitrophthalocyanine immobilized on activated carbon
Abstract
Xanthene derivatives were synthesized by a multicomponent one-pot reaction of aromatic aldehydes, β-naphthol, and 5,5-dimethylcyclohexane-1,3-dione or 1,3-cyclohexanedione upon efficient and eco-friendly catalysis of Fe(III) tetranitrophthalocyanine immobilized on activated carbon in ethanol. The method tolerated a variety of functional groups and the process was carried out under mild conditions to give high yield of products (85–91%) in 30 min. The catalyst can be recycled without any loss in catalytic activity.
Synthesis of novel heptaplatin derivatives and evaluation of their ability to inhibit proliferation of cancer cell lines
Abstract
A series of novel heptaplatin derivatives were synthesized and evaluated for their ability to inhibit growth of two cancer cell lines: human colon carcinoma cell line HCT-8 and human hepatocarcinoma cell line Bel-7402. Majority of the synthesized compounds demonstrated superior activity against cancer cell lines compared to heptaplatin. Specifically, compounds 5a and 5b (5 µg/mL) had more pronounced efficacy against the HCT-8 cell line while 6b and 6c (0.5 µg/mL) had higher efficacy against Bel-7402 cell line.
Synthesis of pyridinecarboxaldimine grafted to magnetic nanoparticles (Fe3O4@SiO2) and its application in the aerobic oxidation of primary alcohols catalyzed by CuBr2/TEMPO
Abstract
A pyridinecarboxaldimine grafted to silica-coated magnetic nanoparticles was prepared. The structure and magnetic properties of the functionalized magnetic silica nanoparticles were identified by TEM, FT-IR, XRD, elemental analysis, and vibrating sample magnetometer (VSM). The supported pyridinecarboxaldimine as chelating ligand in combination with CuBr2 and 2,2,6,6-tetramethyl-1-piperadoxyl (TEMPO) exhibited efficient catalytic performance in the aerobic oxidation of primary alcohols to aldehydes. The functionalized magnetic silica nanoparticles could be easily recovered using an external magnetic field and reused for at least 6 times with low reduction in its performance in the aerobic oxidation of benzyl alcohol.
Synthesis, crystal structure, and magnetic characteristics of chiral cyanide-bridged Fe–Cu complex
Abstract
Based on the building blocks, trans-dicyanide Fe(III) precursor and chiral amine Cu(II) compound, the chiral cyanide-bridged heterometallic Fe(III)–Cu(II) complex with the formula {[Cu(R/R-Chxn)2Fe(bpmb)·(CN)2][Fe(bpmb)(CN)2]}·CH3OH·H2O (1) [bpmb2– = 1,2-bis(pyridine-2-carboxamido)-4-methylbenzenate, R,R-Chxn = R,R-1,2-diaminocyclohexane] has been synthesized and characterized by elemental analysis, IR spectra and X-ray analysis. The latter revealed that the complex contained the cyanide-bridged cationic binuclear entity and free anionic cyanide building block. The complex demonstrated weak ferromagnetic coupling between neighboring Fe(III) and Cu(II) ions via the bridging cyanide group.
Green synthesis of new Ge(IV) complexes with bio-potent ligands and their antimicrobial, DNA cleavage, and antioxidant activities
Abstract
Green microwave supported synthesis, spectral, antimicrobial, DNA cleavage, and antioxidant studies of Ge(IV) complexes with bio-potent ligands, 1-acetylferrocenehydrazinecarboxamide (L1H) and 1-acetylferrocenehydrazinecarbothioamide (L2H) have been carried out. The ligands and their respective complexes have been characterized on the basis of elemental analysis, IR, 1H and 13C NMR spectra, and X-ray powder diffraction studies. The ligands are coordinated to the Ge(IV) via azomethine nitrogen and thiolic sulfur atom/ enolic oxygen atom. Both ligands and their complexes demonstrated appreciable fungicidal and bactericidal properties. The metal complexes demonstrated stronger antimicrobial than the respective free ligands. DNA cleavage activity of the complexes study revealed higher activity of the complexes than the ligands. Antioxidant activity of the complexes was tested for their hydrogen peroxide scavenging.
Charge-transfer complexes of two highly efficient drugs with σ- and π-acceptors: Spectroscopic, thermal, and surface morphology characteristics
Abstract
Considerable attention has recently been devoted to the formation of stable charge-transfer (CT) complexes that result from the reaction of drugs with acceptors. Intermolecular CT interactions of two drugs, barbituratic acid (Bar) and ephedrine hydrochloride (Eph), with different σ- and π-acceptors have been studied stoichiometrically, structurally (IR, Raman, 1H NMR, and UV-Vis spectroscopy), thermally, and morphologically (SEM).
Ag(I), Cu(II), and Cd(II) sulfacetamide complexes: Synthesis, spectral, thermal study, and antimicrobial activity assessment
Abstract
Sulfacetamide complexes of Ag(I), Cu(II), and Cd(II) were synthesized and characterized by the elemental analyses and IR and 1H NMR spectra. Structural assessment revealed two modes of coordination in the sulfacetamide complexes, showing that sulfacetamide reacts as a bidentate ligand and coordinates to Ag(I) and Cd(II) through the amido and sulfonyl oxygens and to Cu(II) through the NH2 nitrogen. Molar conductance measurements in DMSO showed that both the complexes are nonelectrolytes in nature, which allowed they to be assigned the formulas [Ag(SAM-Na)(NO3)H2O)]·3H2O, [Cu(SAM-Na)2(Cl)2], and [Cd(SAM-Na)(Cl)2]·10H2O. The kinetic and thermodynamic parameters of the thermal decomposition reactions of the complexes were estimated from the TG/DTG curves by the Coats–Redfern and Horowitz–Metzeger methods. The surface morphology of sulfacetamide complexes was scanned using X-ray powder diffraction (XRD) and scanning electron microscope (SEM) analyses.