Vol 68, No 2 (2019)
- Year: 2019
- Articles: 29
- URL: https://journals.rcsi.science/1066-5285/issue/view/15043
Reviews
Mercury derivatives of polyhedral boranes, carboranes, and metallacarboranes
Abstract
The review concerns the synthesis, structure, and chemical transformations of mercury derivatives of various polyhedral boron hydrides (carboranes, metallacarboranes, and boranes) and covers a period of time since the pioneering studies of Prof. V. I. Bregadze on chemistry of C- and B-substituted derivatives of icosahedral carboranes C2B10H12 up to date. The emphasis is placed on recent results obtained in this field, in particular, Hg-promoted substitution in nido-carboranes as well as the synthesis and properties of mercury derivatives of monocarbon carborane anion [CB11H12]–.
Full Articles
Application of density functional theory and optical spectroscopy for the prediction of the photophysical properties of Р-pyridylphospholanes
Abstract
The spatial and electronic structure of a series of pyridyl-containing phospholanes, which are potential ligands for the synthesis of luminescent transition metal complexes, was studied using Raman, IR and UV spectroscopy in combination with quantum chemical calculations. A series of model 1-(pyridin-2-yl)phospholane derivatives with various substituents in the pyridyl fragment was considered. Correlations between electronic structure, spectral characteristics, as well as position and nature of substituents were revealed. The obtained results can be used for rational design of complexes with specified optical properties.
Mixed systems based on aminated and sulfonated silica nanoparticles: synthesis, self-assembly, and selective adsorption of certain biopolymers
Abstract
Hybrid aminated and sulfonated nanoparticles were synthesized by surface modification of silica nanopowder with 3-aminopropyltriethoxysilane and 1,3-propanesultone, respectively. The developed protocols for the synthesis of three types of "buffer" mixed submicron particles with corresponding ζ-potentials (–21.4±1.3, 4.7±0.4, 12.4±0.8) were based on various methods of nanoprecipitation of synthesized silica nanoparticles modified by amino- and sulfonate groups, and on various conditions of these precepitation (solvent, temperature). Hybrid SiO2 particles, as well as self-assembling associates based on sulfonated and aminated particles, were examined in extraction of biologically important macromolecules. It was established that the efficiency of adsorption of calf thymus DNA increased with increasing zeta potentials of the modified silica particles studied. The interaction of the studied model proteins (bovine serum albumin and lysozyme) with the synthesized silica nanoparticles modified by sulfonate groups increased as the pH of the medium decreased.
Mechanochemical method of producing triethoxysilane
Abstract
A mechanochemical method for synthesis of triethoxysilane from silicon-copper contact mass and ethyl alcohol in the developed vibration reactor is presented. It is shown that the process of a direct alkoxysilane synthesis in the vibro-boiling layer is affected by a series of control parameters such as the ratio between the contact mass and the mass of grinding bodies, the grinding body sizes and their ratios in a polydisperse mixture, power density. Optimization of these parameters allowed us to obtain HSi(OEt)3 with a selectivity of 50% at a silicon conversion of 90% without the use of promoters.
Mononuclear gallium complexes with the redox-active dmp-bian ligand (dmp-bian is 1,2-bis[(2,6-dimethylphenyl)imino]acenaphthene): synthesis and reactions with alkynes
Abstract
The direct reduction of 1,2-bis[(2,6-dimethylphenyl)imino]acenaphthene (dmp-bian (1)) with gallium metal in toluene affords the solvent-free bis-ligand complex [(dmp-bian)2Ga] (2), in which two diimine ligands are in different oxidation states (radical-anionic and dianionic). The addition of phenylacethylene to the Ga–N–C moiety of the dianionic ligand of compound 2 gives the complex [(dmp-bian)Ga(HC=CPh)(dmp-bian)] (3), in which new Ga–C and C–C bonds are formed. The reaction of 2 with hex-1-yne produces the gallium dialkynyl complex [(dmp-bian)Ga(C≡C–Bu)2] (4), with the metal atom bonded to the dmp-bian radical anion. Paramagnetic compounds 2–4 were characterized by ESR spectroscopy and X-ray diffraction. The known compound dmp-bian was structurally characterized for the first time.
Mixed iodonium-, phosphonium-, arsonium-, sulfoniumdiazonium ylides in reactions with nucleophiles
Abstract
The reactions of mixed ylides containing a diazonium fragment and an "onium" group of different nature with nucleophiles were studied. In the iodonium-diazonium and sulfoniumdiazonium ylide, the nucleophile first of all substitutes the iodonium and sulfonium group. A series of hetaryl-substituted phosphazines was obtained by a one-pot process of nucleophilic substitution in a diazonium-iodonium ylide with subsequent nucleophilic addition of triarylphosphine at the diazo group.
Influence of the composition on the electrochemical properties of cathode materials xLi2MnO3•(1–x)LiMn1/3Ni1/3Co1/3O2 for lithium-ion batteries
Abstract
Lithium-rich transition metal complex oxides of the general composition xLi2MnO3• •(1–x)LiMO2 (M = MnaNibCoc, a + b + c = 1) were synthesized by coprecipitation and modified Pechini method. The influence of the oxide phase composition on their electrochemical performance as cathode materials was studied in lithium half-cells. Effects of the synthetic approach and synthesis conditions on the morphology and electrochemical characteristics of the materials obtained were considered. The composition 0.35Li2MnO3• •0.65LiMn1/3Ni1/3Co1/3O2 demonstrates the highest discharge capacity retention during cycling. The samples with discharge capacity of 290 mA h g–1 were obtained.
Synthesis, microstructure, and electrochemical performance of Li-rich layered oxide cathode materials for Li-ion batteries
Abstract
Li-rich layered oxides Li1.2Mn0.54Ni0.13Co0.13O2 were synthesized by modified Pechini method using various compositions of the reaction mixture. Difference in the electrochemical performance of cathodes on their basis is explained by different morphology and microstructure of the materials. The porous hierarchical structure favors a better electrochemical performance. The presence of defects, including crystal twins, in the samples is considered to be a major reason that leads to their poor cyclability and rate capability.
Mechanism of electrochemical reduction of 5-thio derivatives of 2(5H)-furanone
Abstract
The anionoid elimination of the substituent from position 5 of the lactone ring is the predominant pathway of electrochemical reduction of 5-arylsulfanyl- and 5-arylsulfonyl-3,4-dichloro-2(5H)-furanones in acetonitrile. The contribution of the competing elimination of the chloride ion increases on going to 3,4-dichloro-5-ethylsulfanyl-2(5H)-furanone. An experimental criterion based on the morphology of cyclic voltammograms was proposed for identification of a particular pathway of electroreduction of 2(5H)-furanone derivatives.
Aggregation behavior and solubilization properties of 3-hydroxypiperidinium surfactants
Abstract
Systematic data on the aggregation behavior of novel 3-hydroxypiperidinium surfactants in aqueous solutions were obtained. The ability of the surfactants to solubilize hydrophobic compounds, including the Orange OT dye and biologically active flavonoid quercetin, was characterized. The maximally achieved limiting content of these substances in micellar solutions of 3-hydroxypiperidinium surfactants is by two to three times higher than that in solutions of their non-functionalized analogs. The solubility of quercetin depends on the pH of the medium, and the highest effect observed on going from water to micellar solutions of the studied surfactants reaches two orders of magnitude.
Features of self-organization and biological properties of solutions of citric and succinic acids in low concentrations
Abstract
A relationship between the nonmonotonic concentration dependences of the size of the dispersed phase (nanoassociates), physicochemical properties (electric conductivity, pH, redox potential), and fertility of hydrobionts under the action of solutions of citric (CA) and succinic (SA) acids in low concentrations was established. Solutions of CA stimulate the fertility of Paramecium caudatum infusoria and Chlorella vulgaris algae in a wide range of formation of domains and nanoassociates (1•10–13–1•10–5 mol L–1), whereas solutions of SA exert almost no effect on the fertility and slightly inhibit it only in a range of nanoassociate formation at the calculated concentrations from 1•10–17 to 1•10–14 mol L–1.
Aggregation behavior of the surfactant bearing pyrrolidinium head group in the presence of polyacrylic acid
Abstract
The aggregation characteristics of binary systems based on a novel pyrrolidinium surfactant with the hexadecyl hydrocarbon tail and hydroxyethyl fragment at the nitrogen atom were studied in the presence of polyacrylic acid by a complex of physicochemical methods (tensiometry, conductometry, dynamic light scattering, fluorescence spectroscopy, and spectrophotometry). The formation of surfactant–polyelectrolyte complexes leads to a decrease in the concentration thresholds of aggregation by an order of magnitude to form aggregates ~70 nm in size was established by tensiometry and fluorimetry. The solubilization capacity of the formed mixed aggregates was tested using the Orange OT hydrophobic dye.
The reaction of amidoximes with carboxylic acids or their esters under high-pressure conditions
Abstract
3,5-Disubstituted 1,2,4-oxadiazoles were synthesized by the reaction of amidoximes with carboxylic acids or their esters under high-pressure conditions (10 kbar). The reaction proceeds without the use of other reagents or catalysts. Both aliphatic and aromatic carboxylic acids undergo this reaction. The obtained 1,2,4-oxadiazoles possess high fungicidal activity.
Pressure, temperature, and solvent effects on the rates of reactions of 3,4-dihydro-2H-pyran with tetracyanoethylene and 4-phenyl-1,2,4-triazoline-3,5-dione
Abstract
The effects of high hydrostatic pressure, temperature, and solvent on the rates of reactions of tetracyanoethylene (1) and 4-phenyl-1,2,4-triazoline-3,5-dione (2) with 3,4-dihydro-2Hpyran ( 3) were studied. The X-ray diffraction analysis showed that the reaction of compounds 1 and 3 occurs with the formation of the cyclobutane adduct. The reaction is characterized by enhanced entropy and activation volume, as well as a high influence of the solvent polarity (ET) on the rate (R = 0.975). The course of the reaction 2 + 3 differs sharply from the reaction 1 + 3 by the values of entropy and activation volume, the absence of the effect of the solvent polarity on the rate, and the presence of mono-, di-, and trimeric reaction products. Possible routes of these reactions are considered.
Utilization of potassium carbonate for the synthesis of 2-(organylsulfonyl)thieno[2,3-b]pyridine derivatives
Abstract
A novel preparative method for the synthesis of 2-(organylsulfonyl)thieno[2,3-b]pyridine derivatives has been developed, which allows one to obtain the desired products in a good yield and to shorten the reaction duration. The reaction of 3-cyanopyridine-2(1H)-thiones with chloromethyl organyl sulfones in the presence of potassium carbonate as the base gave 2-(organylsulfonyl) thieno[2,3-b]pyridine-3-amines. The same reaction of methyl 4,6-dimethylpyridine- 2(1H)-thione-3-carboxylate with chloromethyl organyl sulfones resulted in tautomeric mixtures of 4,6-dimethyl-2-(organylsulfonyl)thieno[2,3-b]pyridine-3-oles and 4,6-dimethyl-2-(organylsulfonyl) thieno[2,3-b]pyridine-3(2H)-ones.
Synthesis of new trichloromethyl- and alkoxy-substituted pyrido[2,3-d]pyrimidine derivatives
Abstract
A series of new trichloromethyl- and alkoxy-substituted pyrido[2,3-d]pyrimidine derivatives were obtained from trichloromethyl-substituted pyrimidines with vicinal amino and acyl groups synthesized based on the reaction of trichloroacetonitrile with β-diketone diaminomethylidene derivatives.
Sterically hindered tetrylenes based on new 1,10-phenanthroline-containing diols: initiators for ε-caprolactone polymerization
Abstract
Previously unknown tetradentate ONNO-type ligands 1–5 (4,7-di(4-R´-phenoxy)-2,9- di(HOCR2CH)-1,10-phenanthrolines (R´ = Me, R–R = –(CH2)5– (1), R = Me (2), R–R = 2,2-adamantylene (3); R´ = But, R–R = –(CH2)5– (4), R = Me (5)) were synthesized by sequential treatment of 2,9-dimethyl-4,7-di(4-R´-phenoxy)-1,10-phenanthrolines 6 (R´ = Me) and 7 (R´ = But) with excess LDA and appropriate dialkyl ketone. The structure of compound 4 was determined by single-crystal X-ray diffraction. Previously uncharacterized phenanthroline 6 was synthesized by the treatment of 4,7-dichloro-2,9-dimethyl-1,10-phenanthroline with excess p-cresol in the presence of KOH. The reaction of compounds 1–5 with one equivalent of Lappert´s germylene or stannylene, M[N(SiMe3)2]2 (M = Ge, Sn), gave the corresponding germylenes 8–12 (M = Ge, R´ = Me, R–R = –(CH2)5– (8), R = Me (9), R–R = 2,2-adamantylene (10), R´ = But, R2 = –(CH2)5– (11), R = Me (12)) and stannylenes 13–17 (M = Sn, R´ = Me, R–R = –(CH2)5– (13), R = Me (14), R–R = 2,2-adamantylene (15), R´ = But, R–R = –(CH2)5– (16), R2 = Me (17)) in satisfactory yields. According to 1H, 13C, and 119Sn NMR data, the synthesized stannylenes are monomeric in solution, and the tin atom has a coordination number of 4. In the series of the compounds under consideration, stannylene 16 proved to be the most active initiator for e-caprolactone polymerization, whereas the germylenes were shown to be inactive in this process.
New tetrylenes based on substituted diethylenetriamines: synthesis and use as initiators for ε-caprolactone polymerization
Abstract
The reactions of 3-benzyl-1,5-ditosyl-1,3,5-triazapentane (1) and 3-benzyl-1,5-dimesityl- 1,3,5-triazapentane (2) with one equivalent of Lappert´s germylene or stannylene (M[N(SiMe3)2]2, where M = Ge, Sn) produced germylenes and stannylenes of the general formula PhCH2N(CH2CH2NR)2M, where M = Ge, R = 4-MeC6H4SO2– (3); 2,4,6-Me3C6H2– (5); M = Sn, R = 4-MeC6H4SO2– (4); 2,4,6-Me3C6H2– (6), in satisfactory yields. According to NMR data (1H, 13C, 119Sn), stannylenes 4 and 6 are monomeric in solution, and the coordination number of tin is four. The synthesized stannylenes exhibited very high (compound 4) and moderate (compound 6) activity as initiators for bulk polymerization of ε-caprolactone, resulting in the synthesis of high-molecular-weight polymers with relatively narrow molecular-weight distribution. Previously unknown triamine 2 was synthesized by benzylation of HN(CH2CH2NHMes)2 with benzyl chloride in the presence of K2CO3.
Substrate-induced luminescence response of terbium-containing polymeric vesicles doped with the tetra- and bis-1,3-diketone derivatives of calix[4]arenes bearing nonyl substituents at the lower rims
Abstract
Polymeric aggregates (~100 nm) based on polydiacetylenic acid doped with the luminescent TbIII complexes with the tetra- and bis-1,3-diketonate derivatives of calix[4]arenes with nonyl substituents at the lower rims are considered as potential nanosensors. The obtained colloidally stable mixed aggregates can generate a substrate-induced luminescent response in aqueous solutions of 2,2´,6´,2´´-terpyridine in the micromolar concentration range due to the coordination of the latter by TbIII ions on the aggregate surface.
Lipase enzymatic microreactor in polysaccharide hydrogel: structure and properties
Abstract
An enzymatic microreactor was designed on the basis of sodium alginate hydrogel containing a lipolytic enzyme (Candida rugosa lipase) in the polymer matrix pores. The functional properties of lipase were characterized in polysaccharide hydrogel of different concentrations. The polysaccharide hydrogel matrix was shown to act as a microreactor, where the enzyme retains activity during numerous catalytic cycles and allows designing long-acting drug systems of enzymatic nature.
Synthesis and physicochemical properties of the pectin complexes with Xymedon
Abstract
The formation of stable complexes of pectin polysaccharides with 1-(2-hydroxyethyl)-4,6- dimethyl-1,2-dihydropyrimidin-2-one (Xymedon drug) was shown by UV and IR spectro scopy, dynamic light scattering, and polarimetry. The stoichiometry of the complexes was determined, and their synthesis conditions were optimized. Specific features of the thermal decomposition of pectin and synthesized complexes with Xymedon were studied by the TG/DSC method. The results obtained allow one to substantially extend ranges of using Xymedon in medicine.
Synthesis of N-glycyl-β-glycopyranosylamines, derivatives of main human secreted oligosaccharide core structures
Abstract
β-Glycopyranosylamines were synthesized by the reaction of ammonium carbamate with di-, tetra-, and hexasaccharides, corresponding to the human milk and urine oligosaccharide core structures, in aqueous methanolic solution in the presence of NH3. The N-acylation of these β-glycopyranosylamines with N-Boc-glycine N-hydroxysuccinimide ester followed by removal of the Boc group afforded N-glycyl-β-glycopyranosylamines of the corresponding oligosaccharides in yields of up to 60%.
Synthesis of 4-(2-chloroethoxy)phenyl glycosides and their modification
Abstract
4-(2-Chloroethoxy)phenyl (CEP) aglycon belongs to the class of Janus aglycons and has already been used as a pre-spacer in the synthesis of neoglycoconjugates and as a temporary protective group in the synthesis of oligosaccharides. In the present work, a set of glycosides of various monosaccharides containing CEP aglycon was synthesized. The possibility of modification of CEP aglycon was demonstrated using the corresponding lactoside as an example.
Mixed micellar systems of metal complexes of alkylated N-methyl-d-glucamines with hexadecyltrimethylammonium bromide
Abstract
The spectral, aggregation, and adsorption properties of amphiphilic metal complexes of alkylated N-methyl-D-glucamines and lanthanum nitrate and their mixture with hexadecyltrimethylammonium bromide were studied using IR, UV, and 1H NMR spectroscopy, tensiometry, potentiometry, and dynamic and electrophoretic light scattering. The parameters of aggregation and adsorption at the interface were determined and compared with the parameters of the ligands, ligand–inorganic salt mixtures, and traditional cationic surfactants.
Electrochemical DNA sensors on the basis of electropolymerized thionine and Azure B with addition of pillar[5]arene as an electron transfer mediator
Abstract
A DNA sensor was developed on the basis of glassy carbon electrode coated with polymeric forms of thionine and Azure B. Introduction of carbon black and pillar[5]arene into the electrode composition increases the efficiency of polymerization and the oxidation peak currents of dyes due to the mediating effect of the macrocycle. The addition of DNA onto the sensor surface and into the reaction mixture differently influences the electrochemical activity of poly(Azure B) and polythionine. The control of changes in current-voltage characteristics allowed us to identify the heat denaturation of DNA and its oxidation by reactive oxygen species generated upon the reaction of hydrogen peroxide and copper(II) salt. The DNA sensors can find application in the diagnosis of DNA damage on exposure to carcinogens and in screening of cytotoxic anticancer drugs.
Acyl derivatives of ivermectin 5-oxime with antifungal activity
Abstract
Acylation of ivermectin 5-oxime was first studied. Procedures for selective acylation of ivermectin 5-oxime either selectively at 5-oxime group or at both 5-oxime group and 4″-hydroxy group to give, respectively, mono- and diacyl derivatives were developed. The synthesized compounds exhibit antifungal activity.
Brief Communications
Synthesis and photophysical properties of 2,3,4,5-tetraphenyl-1-n-octyl-1-monophosphole
Abstract
A new method for the preparation of 2,3,4,5-tetraphenyl-1-octyl-1-monophosphole was developed. It was shown that the reaction of n-octyl chloride with a mixture of sodium 1,2,3-tri-and 1-monophospholides obtained by refluxing sodium polyphosphides with diphenylacetylene resulted in the formation of exclusively 1-n-octyl-1-monophosphole. The photophysical properties of 1-n-octyl-1-monophosphole were studied by electron absorption and emission spectroscopy. According to the Raman spectroscopy data, the phenyl moieties of this molecule are efficiently conjugated with the diene system of the heterocycle leading to the appearance of the corresponding absorption and emission bands in the visible spectral range.
Preparation and thermal behavior of the formulation of Ftorsam-39 with SKF-26(ONM) fluorine rubber
Abstract
A synthetic procedure was designed to prepare formulations from Ftorsam-39 monomer (perfluoro-2,5-dimethyl-3,6-dioxanonoic acid triethoxysilylpropylamide) with SKF-26(ONM) fluorine rubber (poly(vinylidene fluoride-co-hexafluoropropylene)) in a presence of AGM-9 (γ-aminopropyltriethoxysilane) as a catalyst and co-reagent. The content of fluorine rubber in the compositions was varied from 10 to 54 wt.%. Thermal properties of the formulations obtained with the ratio Ftorsam-39: SKF-26(ONM): AGM-9 = 40: 54: 6 (wt.%) were assessed using thermomechanical and thermogravimetric analysis and differential scanning calorimetry.