Salts of o,o′-diphenylenephenyloxonium ion

Summary o,o-Diphenylenephenyloxonium sulfate was prepared by us for the first time by heating an aqueous solution of o-phenoxy-o-biphenyldiazonium sulfate; a series of salts of this cation was prepared from this substance by double exchange reactions and the properties of these salts were studied.     

New pentacyclic ring systems: intramolecular cyclization of o,o′-disubstituted bibenzothiazoles

Efficient methods for the preparation of isomeric o,o′-diaminobibenzothiazoles (8a and 11a) and o,o′-diamino-2,2′-dimethylbibenzothiazoles (8b and 11b), potentially valuable building blocks for construction of hitherto unknown dithiazolo annulated pentacyclic heterocycles, have been developed. The dithiazolo annulated benzo[c]cinnolines 9a, 9b, and 12a were prepared from the corresponding diamines by oxidation with PhI(OAc)₂ in good yield. The dithiazolo annulated carbazoles 13 and 14 were efficiently prepared from the corresponding diamines by thermal cyclization in H₃PO₄. The unusual course of reduction and product formation of o,o′-dinitrosubstituted bibenzothiazoles 6a and 6b with SnCl₂ under acidic conditions was rationalized by DFT quantum-mechanical calculations. It was suggested that cyclic products are formed from dinitroso derivatives and open-shell species immediately following on a reduction path.     

Molecular structure and conformations of a sterically hindered aryl derivative of 1,3,4-oxadiazole containing an o,o′-biphenyl ring system

The structure of sterically hindered molecules of 2,2-bis(5-phenyl-1-,3,4-oxadiazol-2-yl)biphenyl has been studied. Crystals that are suitable for x-ray diffraction analysis can be obtained for the different conformers of this compound. It has been found that during synthesis the molecule of this compound is obtained in an energetically less favorable conformation. On the basis of model calculations using the AMI method with geometry optimization it has been proposed that during synthesis there are no changes in conformation of either the intermediates or the final product and the conformation of the resulting oxadiazole system is governed by the conformation of the initial 2,2-diphenic acid dichloride.Khar'kov State University, Khar'kov 310077. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 984–991, July 1996. Original article submitted April 23, 1996.     

Construction of the Skeleton of Phthalascidin,Mechanism of the Formation o the Key Tricyclic Lactam Intermediate

The mechanism of the formation of a key tricyclic lactam intermediate 3 was studied. It was found that the E-form compound 3 was transformed from the Z-form compound 4. The formation of 4 was a kinetically controlled process while the formation of 3 was a thermodynamically favorable one. A possible mechanism was given in this paper.     

Metal Exchange Reactions of o,o′-Dihalosubstituted Cd(II) Tetraphenylporphyrinates with d-Metal Salts in DMF

Russian Journal of General Chemistry - The metal exchange reactions of Cd(II)-5,10,15,20-tetra(2,6-dichlorophenyl) porphyrin and Cd(II)5,10,15,20-tetra(2,6-difluorophenyl) porphyrin with Zn(II) and...     

A General Chemical Method for the Stereochemical Analysis of Nucleoside-5′ [16o,18o] Phosphorothioates

Abstract

A simple chemical method of configurational analysis is presented which will facilitate stereochemical investigation of any restriction endonuclease enzyme reaction.     

Chromaticity characteristics of binary and ternary molybdenum(vi) complexes with o,o’-Dihydroxyazo and heterocyclic azo compounds

The chromaticity characteristics of molybdenum(VI) complexes with o.o’-dihydroxyazo compounds (Lyumogallion IREA and Magnezon IREA) and heterocyclic azo compounds [4-(2-pyridylazo)resorcinol and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol] were studied in the presence and in the absence of the third component, hydroxylamine. It was demonstrated that chromaticity characteristics can be used for analyzing samples with low molybdenum concentrations. The calibration graph equations for the color characteristics of complexes both in solution and in the immobilized exhibit sensitivity coefficients more than an order of magnitude higher than for absorbance and the Kubelka-Munk function     

Synthesis,Structures, and Properties of Novel N‐Aryl‐phenanthren‐o‐iminoquinones

The interaction of 9,10‐phenanthrenquinone with primary amines has been studied. Use of sterically hindered anilines gave the phenanthren‐o‐iminoquinones in good yields. These compounds are structural analogues of o‐benzoquinones. Using single‐electron reduction, o‐iminoquinones may synthesize metal's free‐radical complexes.     

Major and trace element assessment of Tietê river sediments, São Paulo, Brazil

The objective of this study was to quantify major and trace elements present in sediments collected from the one of Brazil’s most important rivers, Tietê River. Sediments from 5 different sampling points (P₀–P₄), in 3 campaigns (2008/2009), from the headwaters to Suzano County upstream from São Paulo city were collected. X-ray fluorescence was applied for measuring total concentration of major elements and instrumental neutron activation analysis (INAA) for trace elements. The elements Cd, Hg and Pb were determined by atomic absorption spectrometry after digestion using the US EPA 3,051 procedure. These metal concentrations were compared to the PEL and TEL oriented values from CCME. The sampling sites P₃ and P₄, near industrialized areas, showed the highest concentrations for potentially bioavailable metals, mainly Pb and Hg. The results obtained by INAA were compared to upper continental crust values. A strong enrichment was found for the elements As, Br, Sb, Th, U and Zn. These results evidenced contamination by industrial effluents and sewage even relatively close to the Tietê River headwaters. The worst biological effects (acute toxicity) on benthonic organism Hyalella azteca were also observed at P₃ and P₄.     

Metals and semi-metals in street soils of São Paulo city,Brazil

São Paulo is the largest city in Brazil and South America with about 20 million inhabitants in the metropolitan area, more than nine million motor vehicles and intense industrial activity, which are responsible for increasing pollution in the region. Nevertheless, little is known concerning metal and semi-metal content in the soils of this metropolitan region. This type of information could be extremely useful as a fingerprint of environmental pollution. The present study determined the elements As, Ba, Co, Cr, Sb, and Zn concentrations in soils adjacent to avenues of highly dense traffic in São Paulo city to assess their levels and possible sources. The analytical technique employed was Instrumental neutron activation analysis. The results showed, except for Co, concentration levels higher than the reference values for soils of São Paulo, according to the Environmental Protection Agency of the State of São Paulo guidelines. When compared to similar studies in other cities around the world, São Paulo soils presented higher levels, probably due to its high density traffic and industrial activity. The concentrations obtained for As and Cr indicate anthropogenic origin. The high levels of the traffic-related elements Ba, Sb, and Zn in soils nearby high density traffic avenues indicate they may originate from vehicular exhausts.     

Synthesis of Cyanobenzaldehydes （m—,o—,p—）by Molecular oxygen Oxidation Methods

Cyanobenzaldehydes (m-,o-,p-) were synthesized by oxidation of corresponding tolunitriles with molecular oxygen,catalyzed by cobalt acetate and sodium bromide.     

Biomonitoring of the atmospheric pollution using lichens in the metropolitan area of São Paulo city,Brazil

The atmospheric pollution of São Paulo city is a serious problem due to the expansion of industrial area, increasing number of vehicles and population density. This work presents results obtained in the analysis of lichens collected in different sites of São Paulo city and in non-polluted areas of Atlantic Forest. Concentrations of twenty elements were determined in Canoparmelia texana species and comparisons were made between the results obtained in lichens from different sites. High concentrations of the elements As, Ba, Cd, Co, Cr, Fe, La, Mn, Sb and Zn were found for samples collected in sites located near industries and petrochemical plant. Br and Sb concentrations were also high in lichens from sites affected by vehicular emissions.     

Influence of some sugars on the thermal,rheological and morphological properties of “pinhão” starch

When starch is incorporated into puddings, desserts, and other foods containing sugar as the main ingredient, it will have an effect on the gelatinisation temperature and pasting properties. Many studies have been undertaken to investigate the effect of several sugars in foods and starches, as well as their physicochemical and functional properties. These studies have verified the significant influence on these properties, which are dependent on the nature of sugar and of starch. In this study, pinhão starch was extracted in the laboratory and was added, stirring for 60 min, to solutions at 1 % of each of the following sugars: fructose, glucose, sucrose, and 0.5 % fructose and 0.5 % glucose. After this time, the slurry was filtered, washed, dried at 40 °C and kept in a desiccator over anhydrous calcium chloride until constant mass. The effects of each sugar on the surface of the pinhão starch granules were observed using the non-contact method of atomic force microscopy, whereby it was possible to verify a decrease in the average diameter and an increase in the average roughness. X-ray diffractometry made it possible to evaluate the degree of relative crystallinity, which was proportional to the roughness and inversely proportional to the gelatinisation enthalpy (ΔH), which was studied by differential scanning calorimetry.     

SOLUBLE POLY-(o, m)-TOLUIDINE

The soluble poly-o-toluidine (POT) and poly-m-toluidine (PMT) have been success-fully prepared under controlled conditions of polymerization and post-treatment, andcharacterized by IR, VPO and elemental analysis. It is found that the soluble and insol-uble polymers obtained with two different methods (Ⅰ and Ⅱ) have the similar conduc-tivity and molecular chain structure. VPO measurement shows that the number averagemolecular weight (Mn) of soluble polymers is about 3000. The mole ratio of benzoidto quinoid is about 3:1 according to ~1H-NMR and elemental analysis. Free-standingfilms of intrinsic POT and PMT have been obtained by casting their CHCl_3, THF orDMF solutions onto a glass surface.     

Effect of aqueous and ethanolic extracts from pinhão coats on the properties of corn and pinhão starches

Journal of Thermal Analysis and Calorimetry - The Araucaria angustifolia seed, named pinhão, has a high content of carbohydrates, and it is considered an unconventional starch source. Its...     

Crystal structure of diaquatetrakis (μ-2,6-dichlorobenzoato-o,o′)dicopper(II)

Summary A new copper(II) complex of the formula [Cu(C₇H₃O₂Cl₂)₂·H₂O]₂ crystallizes in the triclinic system (space group P ). The cell parameters area=7.267(3),b=10.687(3),c= 10.934(3) Å, =99.88(3), =96.25(3), =94.78(3)°,V=827.1(5)ų,Z=1,D _c=1.853(1), andD _m=1.85 Mg/m³. The two copper atoms in the molecule are held together by the four carboxylate groups of the organic ligands, and each copper atom is further bonded to a water molecule, resulting in a square pyramidal geometry. The Cu-O(carboxylate) distances are in the range of 1.955(2)-1.975(2)Å, and Cu-O(water) and Cu-Cu distances are 2.166(2) and 2.605(1)Å, respectively.

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Kristallstruktur von Diaquatetrakis(-2,6-dichlorobenzoato-o,o)dikupfer(II)

Zusammenfassung Ein neuer Kupfer(II)-Komplex mit der Formel [Cu(C₇H₃O₂Cl₂)₂·H₂O]₂ kristallisiert im triklinen System (Raumgruppe P ) mit den Zellparameterna=7.267(3),b=10.678(3),c=10.934(3)Å, =99.88(3), =96.25(3), =94.78(3)°,V=827.1(5)ų,Z=1,D _c=1.853(1) undD _m=1.85 Mg/m³. Die beiden Kupferatome im Molekül werden von den vier Carboxylatgruppen der organischen Liganden zusammengehalten. Jedes Kupferatom ist zusätzlich an ein Wassermolekül gebunden, woraus eine quadratisch pyramidale Geometrie resultiert. Die Cu-O(Carboxylat)-Abstände liegen in einem Bereich von 1.955(2)–1.975(2)Å; die Cu-O(Wasser)- und Cu-Cu-Abstände betragen jeweils 2.166(2) und 2.605(1)Å.

     

Geochronology of sediments in the Cananeia-Iguape estuary and in southern continental shelf of Săo Paulo State, Brazil

Instrumental analysis methods for ²¹⁰Pb, ²²⁶Raand ¹³⁷Cs by gamma-spectrometry in sediments, as well as the sedimentationrates in cores collected from Brazilian coastal region are presented. Samplinglocations have covered the Cananeia-Iguape estuary and the continental shelfof southern Sao Paulo State. Values for ²¹⁰Pb ranged from 122.5to 14.3 Bq . kg ^—1 for estuarine sediments and from 195.5to 23.6 Bq . kg –1 at the continental shelf. For ²²⁶Ra thevalues obtained in sediments varied from 15.2 to 2.3 Bq . kg ^—1 in the estuary and from 30.1 to 16.1 Bq . kg ^—1 atthe continental shelf. Sedimentation rates are variable, ranging from 0.53to 0.98 cm . y ^—1 in estuary sediments and from 0.18 to 0.40cm . y ^—1 at the continental shelf.     

Arsenic in terrestrial invertebrates from riparian areas of the Piracicaba River Basin,São Paulo State,Brazil

There is no information on arsenic distribution in terrestrial invertebrates from riparian forests of urban and rural areas in Brazil. The objective of this study was to evaluate the As levels in invertebrates from riverine forests of the Piracicaba River Basin, São Paulo, Brazil, using the instrumental neutron activation analysis, k ₀-comparator method. After correction of mass fractions, values higher than 0.10 mg kg⁻¹ were quantified in invertebrates from both urban and agricultural areas. An unexpected As mass fraction of 13 mg kg⁻¹ obtained in the Coleopteran pest Macrodactylus pumilio indicated resistance to As-containing-pesticides.

     

Implementation of the k 0-standardization method for analysis of geological samples at the Neutron Activation Analysis Laboratory, São Paulo, Brazil

The Neutron Activation Analysis Laboratory (LAN-IPEN) has been analysing geological samples for many years with the INAA comparative method, for geochemical and environmental research. This study presents the results obtained in the implementation of the k ₀-standardization method at LAN-IPEN, for geological samples analysis, by using the program k ₀-IAEA, provided by the International Atomic Energy Agency (IAEA). The thermal to epithermal flux ratio f and the shape factor α of the epithermal flux distribution of the IEA-R1 nuclear reactor of IPEN were determined for the pneumatic irradiation facility and one selected irradiation position, for short and long irradiations, respectively. To obtain these factors, the “bare triple-monitor” method with ¹⁹⁷Au–⁹⁶Zr–⁹⁴Zr was used. In order to validate the methodology, the geological reference materials basalts JB-1 (GSJ) and BE-N (IWG-GIT), andesite AGV-1 (USGS), granite GS-N (ANRT), SOIL-7 (IAEA) and sediment Buffalo River Sediment (NIST–BRS-8704), which represent different geological matrices, were analysed. The concentration results obtained agreed with assigned, with bias <10 % except for Zn in AGV-1. The U-score test showed that all results, except Mg in JB-1, are within 95 % confidence interval. These results indicate excellent possibilities of using this parametric method at the LAN-IPEN for geochemical and environmental studies.