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A novel synthetic method has been developed to prepare 2-N,N-areno[1,3]tellurazoles following a one step procedure from readily accessible precursors. Products were obtained in yields up to 78% by reacting bis(2-aminoaryl)ditellurides with dialkylformamides in the presence of phosphorous trichloride or phosphorous oxychloride. An analogous approach furnished 2-(N,N-dimethylamino)naphtho[1,2-d][1,3]tellurazole from 3-chloronaphtho[2,1-c]-1,2,5-oxatellurazole. This method was found to be specific to the synthesis of 2-dialkylaminotellurazoles and does not proceed with sulfur or selenium congeners. A characterization of two selected samples by X-ray crystallography found a supramolecular wire motif resulting from intermolecular Te⋯N interactions for one of them. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance spectroscopy (super 2)H MAS NMR was used in this study to evaluate the binding of TNT to a soil and soil components because it would demonstrate the different interactions for deuterated TNT with soil, clays and quartz. For the soil sample used in the research, TNT showed a binding that resembled that of a TNT/K10-montmorillonite sample.

The reductive cyclization of arenetellurols carrying α,β-unsaturated amide functionalities in the ortho position was investigated. Conceptually, such compounds can form 1,3-tellurazoles without the involvement of the unsaturation in the ring closure, they can form 1,4-tellurazinone derivatives, or they can undergo ring closure to 1,5-tellurazepinones. Amides derived from acrylic and methacrylic acid generated 1,5-tellurazepinones while 2-cinnamylamidobenzenetellurol cyclized to a 1,3-tellurazole derivative. In contrast, the reaction of acetylenedicarboxylic acid and its derivatives with 2-aminoarenetellurols generated 1,4-tellurazepinones, including a derivative of novel tricyclic naphtho [1, 4]tellurazinone. A comparison with analogous reactions of sulfur congeners indicates that their chemistry is a good predictor for the products obtained from 2-aminoarenetellurols. Selected compounds were characterized by X-ray crystallography. The present work offers access to previously unexplored organotellurium heterocycles. [ABSTRACT FROM AUTHOR]

The synthesis and use of the perdeuterio 2,2,2-trifluoro-1-(9-anthryl)ethanol as a chiral solvating agent are described. Results discuss 'chiral self-discrimination' with respect to the enantiomers of (R) and (S) perdeuterio 2,2,2-trifluoro-1-(1-pyrenyl)ethanol.

Condensation of 2,3-dichloropyrazine with 2-aminobenzenetellurole and 2-amino-5-methylbenzenetellurole, generated in situ by reduction of the corresponding ditellurides, resulted in the formation of novel 10H-pyrazino[2,3-b][1,4]benzotellurazine and its 7-methyl derivative. The products were purified via their well-crystallized 5,5-dibromo derivatives. X-ray crystallographic analysis of the title compound indicates that it has a pronounced V-shape and forms hydrogen-bonded dimers. Te, N-containing heterocycles have the potential of offering access to supramolecular assemblies. [ABSTRACT FROM AUTHOR]

Novel methods for the preparation of organotellurium heterocycles derived from bis(2-aminophenyl) ditelluride were developed. Thus, highly 2-aminobenzenetellurol generated by reduction in situ reacted smoothly with malonitrile to 2-cyanomethylbenzo-1,3-tellurazole, while its treatment with and subsequent generated 2-methylmercaptobenzo-1,3-tellurazole. to (2-haloacetamidophenyl) ditellurides, followed by reduction under carefully controlled conditions, furnished previously inaccessible 2 H-1,4-benzotellurazin-3(4 H)-ones in yields ranging from 47-62%. [ABSTRACT FROM AUTHOR]

A series of dinuclear metal(ii)-acetato complexes: [Ni2(μ-LClO)(μ2-OAc)2](PF6)·3H2O (1), [Ni2(μ-LClO)(μ2-OAc)2](ClO4)·CH3COCH3 (2), [Cu2(μ-LClO)(μ2-OAc)(ClO4)](ClO4) (3), [Cu2(μ-LClO)(OAc)2](PF6)·H2O (4), [Zn2(μ-LClO)(μ2-OAc)2](PF6) (5) and [Mn2(LCl-O)(μ2-OAc)2](ClO4)·H2O (6), where LClO− = 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-chlorophenolate, were synthesized. The complexes were structurally characterized by spectroscopic techniques and single crystal X-ray crystallography. Six-coordinate geometries with doubly bridged acetato ligands were found in Ni(ii), Zn(ii) and Mn(ii) complexes 1, 2, 5 and 6, whereas with Cu(ii) complexes a five-coordinate species was obtained with 4, and mixed five- and six-coordinate geometries with a doubly bridged dimetal core were observed in 3. The magnetic properties of complexes 1–4 and 6 were studied at variable temperatures and revealed weak to very weak antiferromagnetic interactions in 1, 2, 4 and 6 (J = −0.55 to −9.4 cm−1) and ferromagnetic coupling in 3 (J = 15.4 cm−1). These results are consistent with DFT calculations performed at the B3LYP/def2-TZVP(-f) level of theory. Under physiological conditions, the interaction of the dinculear complexes 1–5 with supercoiled plasmid ds-DNA did not show any pronounced nuclease activity, but Ni(ii) complexes 1 and 2 revealed a strong ability to unwind the supercoiled conformation of ds-DNA. The mechanistic studies performed on the interaction of the Ni(ii) complexes with DNA demonstrated the important impact of the nickel(ii) ion in the unwinding process. In combination with the DNA study, the phosphatase activity of complexes 1, 3, and 5 was examined by the phosphodiester hydrolysis of bis(2,4-dinitrophenol)phosphate (BDNPP) in the pH range of 5.5–10.5 at 25 °C. The Michaelis–Menten kinetics performed at pH 7 and 10.7 showed that catalytic efficiencies kcat/KM (kcat = catalytic rate constant, KM = substrate binding constant) decrease in the order: Ni(ii), 1 ＞ Zn(ii), 5 ＞ Cu(ii), 3. A similar trend was also observed with the turnover numbers at pH = 7. The results are discussed in relation to the coordination geometry and nature of the metal center as well as the steric environment imposed by the compartmental phenoxido ligand. [ABSTRACT FROM AUTHOR]

There is a paucity of data concerning the structures of six- and seven-membered tellurium- and nitrogen-containing (Te-N) heterocycles. The title compounds, C8H7NOTe, (I), and C9H9NOTe, (II), represent the first structurally characterized members of their respective classes. Both crystallize with two independent molecules in the asymmetric unit. When compared to their sulfur analogs, they exhibit slightly greater deviations from planarity to accommodate the larger chalcogenide atom, with (II) adopting a pronounced twist-boat conformation. The C-Te-C angles of 85.49 (15) and 85.89 (15)° for the two independent molecules of (I) were found to be somewhat smaller than those of 97.4 (2) and 97.77 (19)° for the two independent molecules of (II). The C-Te bond lengths [2.109 (4)-2.158 (5) Å] are in good agreement with those predicted by the covalent radii. Intermolecular N-H...O hydrogen bonding in (I) forms centrosymmetric R22(8) dimers, while that in (II) forms chains. In addition, intermolecular Te...O contacts [3.159 (3)-3.200 (3) Å] exist in (I). [ABSTRACT FROM AUTHOR]

We review the techniques and results of the searches for the Higgs boson performed by the two Tevatron collaborations, CDF and DØ. The Higgs boson predicted by the Standard Model was sought in the mass range 90 < mH < 200 in all main production modes at the Tevatron: gluon-gluon fusion, WH and ZH associated production, vector boson fusion, and production, and in five main decay modes: , H→τ+τ-, H→WW(*), H→ZZ(*) and H→γγ. An excess of events was seen in the searches consistent with a Standard Model Higgs boson with a mass in the range 115 < mH < 135 . Assuming a Higgs boson mass of mH = 125 , studies of Higgs boson properties were performed, including measurements of the product of the cross section times the branching ratio in various production and decay modes, constraints on Higgs boson couplings to fermions and vector bosons, and tests of spin and parity. We also summarize the results of searches for supersymmetric Higgs bosons, and Higgs bosons in other extensions of the Standard Model. [ABSTRACT FROM AUTHOR]

The reaction of a methanolic solution containing the bi-compartmental phenolic ligand 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-chlorophenol (LCl-OH) with MCl2·nH2O in the presence of NH4PF6 or NaClO4 afforded the dinuclear bridged-phenoxido dichlorido-metal(ii) complexes [Co2(μ-LClO)(H2O)2Cl2][Co2(μ-LClO)(MeOH)2Cl2](PF6)2 (1), [Ni2(μ-LClO)(MeOH)2Cl2]PF6 (2), [Ni2(μ-LClO)(MeOH)(H2O)Cl2]ClO4·1.25H2O (3), [Cu2(μ-LClO)Cl2]PF6·1/2MeOH (4) and [Zn2(μ-LClO)Cl2]PF6·MeOH (5). The complexes were characterized by elemental microanalyses, conductivity measurements, IR and UV-Vis spectroscopy, mass spectrometry and single crystal X-ray crystallography. Each M(ii) center within the dinuclear complex cations is octahedrally coordinated in complexes 1–3, and five-coordinated distorted square pyramidal in 4 and 5. Magnetic susceptibility measurements at variable temperature of the complexes 1–4 revealed weak to moderate antiferromagnetic coupling with ☋J☋ values = 8.38, 39.0, 30.2 and 0.79 cm−1, respectively. The results of DFT calculations correlate well with the experimentally determined antiferromagnetic coupling and show that the magnetic exchange coupling occurs mainly through the phenoxido bridge M–O–M. Implications of geometry around the central metal ion, M…M distance, M–O–M bond angle and overlapping of magnetic orbitals on the magnetic exchange coupling are discussed.UGRAPHIC ID="UGR1" SRC="UGR1"/ [ABSTRACT FROM AUTHOR]

Benzo-1,3-tellurazoles carrying alkyl or aryl substituents in position 2 were prepared in a facile two-step sequence, starting with readily available 2-haloanilines. This approach relies on the preparation of bis(2-aminophenyl) ditellurides by nucleophilic halide displacement from 2-haloanilines with sodium telluride in N-methylpyrrolidone. Subsequent reductive cyclization with carboxylic acid halides or carboxylic anhydrides furnished benzo-1,3-tellurazoles in good yields. [ABSTRACT FROM AUTHOR]

The field of experimental particle physics has become more sophisticated over time, as fewer, larger experimental collaborations search for small signals in samples with large components of background. The search for and the observation of electroweak single top quark production by the CDF and DØ Collaborations at Fermilab's Tevatron collider are an example of an elaborate effort to measure the rate of a very rare process in the presence of large backgrounds and to learn about the properties of the top quark's weak interaction. We present the techniques used to make this groundbreaking measurement and the interpretation of the results in the context of the Standard Model. [ABSTRACT FROM AUTHOR]

In the proton–antiproton collisions at Fermilab, individual top quarks are expected to be produced by an electroweak mechanism referred to as single-top-quark production. In this paper we review the CDF results of the search for single-top-quarks, along with the prospects for the current collider run. [ABSTRACT FROM AUTHOR]

Investigates the effects of hydrology on biogeochemical processes relevant to pollutant chemical transformation in wetland sediments. Design of microcosms; preservation of wetland integrity and tidal hydrology; Range of natural and anthropogenic organic chemicals.

Discusses the molecular structure of tribromo(3,5-dimethyl-2-nitro-phenyl-κ²C¹,O)tellurium(IV) , bromo(3,5-dimethyl-2-nitrophenyl-κ²C¹,O)tellurium(II) and bromo(3,5-dimethyl-2-nitroso-phenyl-κ²C¹,O)tellurium(II). Intramolecular tellurium-oxygen coordination; Tellerium-oxygen bond distances; Comparison between the three organotellurium compounds.

The reaction of Cu(II) salts with 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4- t -butylphenol (L t-Bu -OH) afforded two bridged-phenoxido/hydroxido complexes. The dinuclear bridged acetate species [Cu 2 (μ-L t-Bu -O)(μ-CH 3 COO)](PF 6 ) 2 ( 1 ) and the 1D polymeric doubly-bridged-chlorido {[Cu 2 (μ-L t-Bu -OH)(μ-Cl) 2 ](ClO 4 ) 2 ·4H 2 O} n ( 2 ). The two complexes were structurally characterized. Both complexes revealed ferromagnetic interactions; moderate in complex 1 ( J = + 30.8 cm − 1 ) and very weak ( J = + 2.25 cm −1 ) in 2 . [ABSTRACT FROM AUTHOR]

The two dinuclear complexes [Cu 2 (L Me O-tmpa)(OAc) 2 ]PF 6 ·H 2 O ( 1 ) and [Cu 2 (L Me O-tmpa)(N 3 ) 2 ]ClO 4 ( 2 ), where L Me -OH-tmpa = 2,6-bis[bis(pyridine-2-ylmethyl)aminomethyl]-4-methylphenol, were synthesized and structurally and magnetically characterized. The five-coordinate geometry around the Cu(II) centers is achieved through the monodentate-acetato or -azido groups, the three N-donors of the ligand and a bridged-phenoxdio group. The two complexes reveal weak antiferromagnetic interaction. [ABSTRACT FROM AUTHOR]

Methods for the preparation of deuterium-labeled analogs to six prominent biotransformation products of the explosive 2,4,6-trinitrotoluene were developed. These are useful as reference standards for stable isotope dilution techniques and for solid state 2H NMR spectroscopic studies. Although syntheses for most of the target compounds in protiated form had been reported in the past, most of those were found to be poorly suited for the preparation of the deuterated materials. Selective reduction of [2H5]trinitrotoluene furnished [2H5]-4,6-dinitro-2-hydroxylaminotoluene, [2H5]-2,6-dinitro-4-hydroxylaminotoluene, [2H5]-2-amino-4,6-dinitrotoluene, and [2H5]-4-amino-2,6-dinitrotoluene. The syntheses of [2H10]-2,2′-azo-4,4′,6,6′-tetranitrotoluene and [2H10]-4,4′-azo-2,2′,6,6′-tetranitrotoluene were accomplished by selective oxidation of [2H5]-2-amino-4,6-dinitrotoluene and [2H5]-4-amino-2,6-dinitrotoluene, respectively. [ABSTRACT FROM AUTHOR]

The title compound, C8H4ClNO2Te, represents the first reported example of a benzofuran-derived 2,1,3-benzoxatellurazole derivative. While it can be formally described as a nitrosoaryltellurium monochloride, its Te-O and Te-C bond lengths of 2.1421 (14) and 2.0374 (17) Å, respectively, characterize it as a planar tricyclic aromatic containing a Te=C double bond. Its formation suggests that derivatives of 2-cyclohexenone oxime in general react with tellurium dioxide to form aryl-2,1,3-benzoxatellurazoles. [ABSTRACT FROM AUTHOR]

The article discusses the evidence for the production of single top quarks in proton-antiproton collisions. The top quark, the heaviest known elementary particle, was first observed in experiments at the Tevatron collider at the Fermi National Accelerator Laboratory. Top quarks are commonly produced through the top-antitop process. A comparison between the top-antitop process and the process of producing single top quarks in proton-antiproton collisions is presented.

This work examines the use of ultrasound to mineralize 4-chlorophenol, 2,4-dichlorophenol, [aryl-2H3]2,4-dichlorophenol, 4-chloro-3,5-dimethylphenol, 4-fluorophenol, 2,4,6-trinitrotoluene, 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene in dilute aqueous solution. Mineralization rates were determined as a function of substrate structure and concentration, bulk phase temperature, pH and the presence of co-solutes such as detergents and humic acids. All substrates were found to degrade sonochemically, as evidenced by the release of Cl− and NO3−, respectively. Product analyses by GC–MS, HPLC, and micellar electrokinetic capillary chromatography (MECC) indicated mineralization with little formation of organic byproducts, a significant advantage over other remediation methods. Chloride release from chlorophenols was approximately proportional to substrate total chlorine content, irrespective of structural differences, and reached 80% of the theoretical limit. Fluoride release from 4-fluorophenol was ca. 10-fold lower than that of chloride from 4-chlorophenol. Changes in the bulk phase temperature from 9.5 to 34 °C, and 12.5 to 30 °C, respectively, were of little consequence to observed mineralization rates for nitroaromatics and chlorophenols. A significant mineralization rate increase resulted from sonication of 4-chlorophenol in acidified media. Additions of amphiphilic co-solutes resulted in modest, but statistically significant, sonolysis enhancements. [Copyright &y& Elsevier]

Arylboronic acids were treated with tellurium tetrachloride to generate substituted aryltellurium trichlorides, which were reduced to the corresponding diaryl ditellurides in good to excellent overall yields. Representative products include diphenyl ditelluride, bis(2-nitrophenyl) ditelluride, bis(3-nitrophenyl) ditelluride, bis(4-methylphenyl) ditelluride and bis(2-chlorphenyl) ditelluride. 3,5-Dimethylphenyl 2′-nitrophenyl telluride and 3,5-dimethylphenyl 3′-nitrophenyl telluride were prepared in analogous fashion, in modest yields, from 3,5-dimethylphenyltellurium tribromide and the corresponding nitrophenylboronic acids. [Copyright &y& Elsevier]