GENERAL APPROACH TO THE SYNTHESIS OF SYMMETRICAL 1,3,2-DIAZAPHOSPHOCANES

Abstract

Synthesis of eight-membered phosphorus-nitrogen heterocycles has been performed by phosphocyclization of the corresponding diamines using different derivatives of phos horous acid. The structures of diazaphosphocanes were supported by elemental analysis; ¹H, ¹³C, and ³¹PNMR spectroscopy; and x-ray diffraction analysis.     

Analysis of Cyanide in Blood by Headspace-Isotope-Dilution-GC-MS

Abstract

An uncomplicated, rapid, automated procedure for the analysis of low cyanide concentrations in whole blood is reported. The analysis was performed by headspace gas chromatography and mass spectrometry in the (¹H¹²C¹⁴N) and m/z 29 (¹H¹³C¹⁵N). Carryover from cyanide adsorption onto the surface of the needle was prevented by developing a new method that enabled automated flushing of the needle in between each cyanide analysis. Results were compared of ordinary calibrations and those of isotope dilutions. The total time of analysis was 18 min for a single cyanide analysis.     

Non-destructive gamma-spectrometry analysis of cosmogenic radionuclides in fragments of the Ko?ice meteorite

Results of analysis of cosmogenic radionuclides (^57,58,60Co, ⁵⁴Mn, ⁴⁶Sc, ²²Na, ⁴⁸V and ²⁶Al) in fragments of the Ko?ice meteorite are presented and discussed. Analyses were carried out using a low-level HPGe-spectrometer placed in a lead-iron-copper shield. Twelve meteorite fragments were available for the analysis with masses from 27 to 2,163?g. The lowest massic activities were observed for ⁴⁶Sc (down to 0.1?mBq/g), and the highest for ²²Na (up to 2?mBq/g). The measured radionuclide activities showed differences between fragments, as indicated mainly by the ⁶⁰Co data, which were caused by different positions of meteorite fragments from the center of the meteorite body.     

Label-free capacitive immunosensor based on quartz crystal Au electrode for rapid and sensitive detection of Escherichia coli O157:H7

The capability of ICP-MS equipped with the high matrix introduction system (HMI) for accurate analysis of lanthanoids in environmental samples was investigated. Compared to the conventional operation, the amounts of oxide and hydroxide molecular species formed in the plasma were reduced by up to 5 times. The relative yields of oxides did not exceed 0.02% for BaO⁺ species and were as low as 0.3% for lanthanoids with the highest oxide-formation rates (LaO⁺, CeO⁺, PrO⁺ and NdO⁺). Hydroxide formation was less than 0.02% when HMI system was used. In addition, two digestion procedures were evaluated by the analysis of standard reference materials (SRMs) of different matrices. The digestion efficiency and limits of detection (LOD) were improved when samples were digested with a mixture of HNO₃/H₂O₂/HCl/HF, and HF was removed by evaporation in presence of concentrated HCl. Using this procedure and HMI-ICP-MS analysis, LOD ranged from 0.1 μg kg⁻¹ to 6 μg kg⁻¹. Recoveries ranged from 85 to 115% for La to Ho and from 75 to 85% for the other lanthanoids. Relative standard deviations for replicate analysis of SRMs were less than 10%.     

Synthesis, Structure and H+/K+-ATPase Inhibitory Activity of Novel Triazolyl Substituted Tetrahydrobenzofuran Derivatives via One-pot Three-component Click Reaction

Eleven triazolyl substituted tetrahydrobenzofuran derivatives were synthesized in high yields as novel H⁺/K⁺‐ATPase inhibitor via one‐pot CuI‐catalyzed three‐component click reaction of azide, secondary amine and 3‐bromopropyne under mild conditions in water. Their structures were characterized by NMR, IR, ESI‐MS, elemental analysis and single‐crystal X‐ray diffraction analysis. Most of the target compounds exhibited better H⁺/K⁺‐ATPase inhibitory activity than commercial omeprazole with IC₅₀ values less than 15 µmol·L^?1. The initial structure‐activity analysis suggested that the triazole substituted by cycloalkyl, aromatic ring or O‐containing side‐chain seemed to be beneficial for enhancing the activity.     

Friedel-Crafts Polymers. 6. Friedel-Crafts Polycondensation of p-Xylylerte Dibromide with Salicylic Acid and β-Resorcyiic Acid

Polymers were prepared by condensing p-xylylene dibromide separately with salicylic acid and β-resorcylic acid in the presence of anhydrous ferric chloride in dioxane. The polymer samples_were characterized by elemental analysis, by IR spectral study, by M determined by vapor pressure osmometry, by nonaqueous conducto-metric titration in pyridine, by TGA in air, and by viscosity measurements of polymer solutions in DMF. Polymeric metal chelates of Cu²⁺, Co²⁺, Zn²⁺, Ni²⁺, and Fe³⁺ with polymer samples were prepared and characterized by elemental analysis, by IR spectral study, and by TGA in air. The chelation ion-exchange properties of the polymer samples were studied by employing the batch equilibration method.     

Analysis of 210Pb and 210Po in Brazilian foods and diets

Radiochemical procedures for the analysis of ²¹⁰ Pb and ²¹⁰ Po in foods and diets are presented. Because of the low beta energy of ²¹⁰ Pb, its analysis was based on a separation of the daughter radionuclide ²¹⁰ Bi by precipitation of lead sulphate, ²¹⁰ Bi ingrowing and beta counting of this nuclide. ²¹⁰ Po analysis was based on wet dissolution of the sample, deposition onto silver disc and counting by alpha-spectrometry. Levels of these radionuclides in individual items and diets of selected university students were determined in order to evaluate the intakes of ²¹⁰ Pb and ²¹⁰ Po as well as the dose due to ingestion of foods and diets in São Paulo city.     

Determination of actinide nuclides in water samples from the primary circuit of a research reactor

Primary coolant samples from a research have been analyzed for^239,240Pu,²³⁸Pu,²³⁸U,²³⁷Np and²³⁹Np. The determination of²³⁷Np and²³⁸U was carried out with the help of isotope dilution neutron activation analysis with²³⁹Np or²³⁸Np as tracer. For determination of^239,240Pu and²³⁸Pu alpha spectroscopic isotope dilution analysis with²³⁸Pu as tracer was used.²³⁹Np was determined with the help of isotope dilution analysis using²³⁸Np as tracer. Nuclides were isolated by chemical separation on anionite resin. Before measurement, Pu isotopes were electrolytically deposited on stainless steel plates. Activity ratios referred to²³⁸U were reported. They are helpful for identification of the sources of actinide activity in reactor effluents.     

Roof shape amines: synthesis and application as NMR chiral solvating agents for discrimination of α-functionalized acids

A series of new chiral roof shape amines have been prepared from anthracene involving simple chemical steps and enzymatic resolution of isomers. The amines were screened as chiral solvating agents for the discrimination of enantiomers of several α-functionalized acids by the ¹H NMR analysis. The system can also be used to accurately measure enantiomeric excess of mandelic acid by ¹H NMR analysis. The roof shape CSAs were capable of detecting the shift in the signals for the standard four nuclei of ¹H, ¹³C, ¹⁹F and ³¹P of various optically active acids.     

Cobalt（Ⅱ） Salen Complex with Two Aza-crown Pendants and Its Analogues as Synthetic Oxygen Carriers

Salen with two aza‐crown ether pendants H₂L¹ and its analogues H₂L^2‐H₂L⁴ were successfully synthesized starting from benzo‐10‐aza‐15crown‐5 (BN15C5) or morpholine. Their structures were characterized by IR, MS, ¹H NMR and elemental analysis, and were confirmed by X‐ray diffraction analysis of H₂L¹. Moreover, the saturated oxygen uptake of their cobalt(II) complexes CoL^1‐CoL⁴ in diethyleneglycol dimethyl ether was determined at different temperature. The oxygenation contants (K_O2 ) and thermodynamic parameters (ΔH° and ΔS°) were calculated. The modulation of O₂‐binding capabilities by pendant substituents were investigated as compared with the parent Schiff base complex CoL⁵ (CoSalen). The results indicate that the dioxygen affinities of CoL have been much more enhanced by aza‐crown pendants than that by morpholino pendants, and the O₂‐binding capabilities of CoL¹ and CoL² with aza‐crown pendants would also be enhanced by adding alkali metal cations.     

Synthesis,spectral, thermal,and flammability studies of phenolphthalein polyphosphate esters

Polyphosphate esters were synthesized from phenolphthalein and aryl phosphorodichloridates by interfacial polycondensation using a phase transfer catalyst. The polymers were characterized by IR, ¹H-, ¹³C-, and ³¹P-NMR spectroscopy. The molecular weights were calculated by end group analysis using ³¹P-NMR spectral data. The thermal stability of the polymers was studied by thermogravimetry and the flammability was investigated by measuring limiting oxygen index values.     

Zinc oxide nanostructured platform for electrochemical detection of heavy metals

ZnO nanoparticles (ZnO-NP) were prepared by a facile precipitation technique using di-isopropyl amine as precipitating agent. The morpho-structure and porosity of the as-prepared nano-powder were investigated by FT-IR analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and BET analysis. By drop-casting, a composite film was deposited to obtain ZnO-NP-Nafion/GCE modified electrode. The modified electrode was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and square wave anodic stripping voltammetry (SWASV) for the detection of Pb²⁺, Cd²⁺, Cu²⁺, and Fe³⁺, and it was successfully applied for the detection of Pb²⁺ and Cu²⁺ in real water samples.     

Geographical Discrimination of Honeysuckle (Lonicera japonica Thunb.) from China by Characterization of the Stable Isotope Ratio and Multielemental Analysis

A total of 117 honeysuckle (Lonicera japonica Thunb.) samples from four major regions of production in China, including Fengqiu in Henan, Pingyi in Shandong, Julu in Hebei, and Xiushan in Chongqing, were analyzed to determine their geographical origin. δ¹³C, δ¹⁵N, and δ¹⁸O values were determined by isotope ratio mass spectrometry (IRMS), and the contents of 18 elements (Fe, Mn, Cu, Zn, K, Ca, Mg, Pb, Cd, Cr, As, Hg, Se, Sr, Ni, Co, B, and Mo) were measured by inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). Multivariate statistical analysis by analysis of variance (ANOVA), principal component analysis (PCA), and linear discriminant analysis (LDA) were performed. The results showed that there were very significant differences in the stable isotope ratios and elemental concentrations in honeysuckle based on geographical origin, with plants from each region having a unique fingerprint. Discriminant functions were established to distinguish the origin of honeysuckle using suitable indicators including Cd, Cr, As, Hg, Se, Co, Ni, Sr, Fe, δ¹³C, δ¹⁵N, and δ¹⁸O. Cross-validated cases of 95.7% were correctly classified.     

Recovery of plutonium from aqueous waste solutions using porous zirconia spherical particles

Based on the Linssi database and UniSampo/Shaman software, an automated analysis platform has been setup for the analysis of large amounts of gamma-spectra from the primary coolant monitoring systems of a CANDU reactor. Thus, a database inventory of gaseous and volatile fission products in the primary coolant of a CANDU reactor has been established. This database is comprised of 15,000 spectra of radioisotope analysis records. Records from the database inventory were retrieved by a specifically designed data-mining module and subjected to further analysis. Results from the analysis were subsequently used to identify the reactor coolant half-life of ¹³⁵Xe and ¹³³Xe, as well as the correlations of ¹³⁵Xe and ⁸⁸Kr activities.     

Two Coordination Polymers based on a Flexible Tritopic Pyridyldicarboxylate Ligand: Structures and Magnetic Properties

The coordination polymers, [Ni(L)₂]_n ( 1 ) and [Mn₂(L)₂(DMF)₂(H₂O)]_n ( 2 ) were synthesized by using a tritopic ligand 5‐(4′‐carboxylphenoxy)nicotinic acid (H₂L). The structural analysis shows that compound 1 exhibits a ten‐connected three‐dimensional (3D) architecture with the point symbol 3¹².4²⁶.5⁷, 2 displays an eight‐connected topology network with a point symbol of 4²⁴.6⁴. The structures and formulas of 1 and 2 were determined by X‐ray diffraction, elemental analysis, and thermogravimetric analysis (TGA). In addition, the magnetic behaviors for 1 and 2 were investigated.     

Radiochemical determination of the yields of transuranium nuclides produced from natural uranium irradiated in a reactor

Transuranium nuclides were produced by irradiating a pellet of natural uranium sulfide in the Japan Material Testing Reactor (JMTR). After irradiation, a successive separation of uranium, plutonium, americium and curium was carried out. The fractional concentrations of the nuclides²³⁸Pu,²³⁹Pu,²⁴⁰Pu,²⁴¹Am,²⁴³Am,²⁴²Cm and²⁴⁴Cm were determined by α-ray spectrometry, and those of²⁴¹Pu and^242mAm were estimated from the build-up of α-emitting daughters,²⁴¹Am and²⁴²Cm, respectively. As the yield of²⁴²Pu was too slight to be detected by α-counting, the neutron activation analysis of the plutonium fraction based on the²⁴²Pu(n, γ)²⁴³Pu reaction was carried out by γ-ray spectrometry, and it was shown that a few pg of²⁴²Pu could be determined. A burn-up of²³⁵U was also estimated by neutron activation analysis. The experimental results are compared with the calculated ones.     

Organoborazines. III. Homo- and copolymerization of p-vinylphenylcyclotriborazines

The polymerization and copolymerization with styrene of a series of unsymmetrically B-p-vinylphenyl-N-methyl and N-phenyl borazines [R³(R²)₂B₃N₃(R¹)₃; R¹ = methyl, phenyl, R² = methyl phenyl, R³ = p-vinylphenyl] has been studied. The polymerization of these monomers yielded both tractable and crosslinked materials. The polymers obtained were characterized by ¹H- and ¹³C-NMR spectroscopy, elemental analysis, gel permeation chromatography, and thermogravimeteric analysis. The reactivity ratios for the copolymerization reaction were calculated by the Mortimer-Tidwell method.     

Thiophene and diethylaminophenol-based “turn-on” fluorescence chemosensor for detection of Al3+ and F− in a near-perfect aqueous solution

A new fluorescent sensor 1, based on thiophene and diethylaminophenol moieties, has been synthesized and its binding capabilities for metal-ion and anion recognition were investigated. The sensor 1 showed ‘turn-on’ fluorescence in the presence of Al³⁺ and F^?. The sensing behaviors of 1 with Al³⁺ and F^? were studied by using photophysical experiments, ¹H NMR titration, and ESI-mass spectrometry analysis. The detection limits for the analysis of Al³⁺ and F^? were found to be 0.41 μM and 14.36 μM, respectively, which are below the WHO guidelines for drinking water (7.41 μM for Al³⁺ and 79 μM for F^?). Moreover, turn-on fluorescence of 1 toward Al³⁺ and F^? caused by intramolecular charge transfer (ICT) was well explained by density functional theory (DFT) calculations. Importantly, 1 could be used to detect Al³⁺ in the living cells.     

Crystal structures,semiempirical PM3 calculations and NMR studies of trimesityllead bromide and dimesityllead dibromide

Trimesityllead bromide has been synthesized by the reaction of mesityllithium with lead(II) chloride in tetrahydrofuran (THF). As a side product, dimesityllead dibromide was formed. The structures of both compounds were determined by single-crystal X-ray diffraction analysis. Both Mes₃PbBr and Mes₂PbBr₂ were characterized by NMR (¹H, ¹³C and ²⁰⁷Pb) and other spectroscopic methods. ²⁰⁷Pb–¹H and ²⁰⁷Pb–¹³C coupling constants were determined. The experimentally obtained X-ray data were compared with those calculated at the semiempirical PM3 level.