Recoil chlorine reactions with ethylene

The reactions of recoil³⁸Cl atoms produced through the³⁷Cl(n,)³⁸Cl process in the CF₃Cl–C₂H₄ gas phase are described in this work. The CF₃Cl is a chlorine source as well as moderator. Scavengers, such as O₂ and H₂S, were added to the system to discriminate the reactions induced by energetic and/or thermal chlorine atoms. The radioactive³⁸Cl-labeled products were separated using gas-chromatogarphic technique followed by an external proportional counter for quantitative determination of the product yeids. The mechanisms of the chemical reactions are predicted to account for the formation of these organic compounds.     

Theoretical study of the C3Cl radical and its cation

A theoretical study of C₃Cl and C₃Cl⁺ isomers has been carried out. The global minimum for C₃Cl is a cyclic C_2V species (a three-membered ring with an exocyclic chlorine atom). However, a quasi-linear CCCCl structure is predicted to lie only 3-5 kcal mol⁻¹ higher. This quasi-linear structure is floppy, since the linear arrangement lies only 2-3 kcal mol⁻¹ higher in energy. The cyclic and open-chain isomers have dipole moments of 1.986 and 3.363 D, respectively. In C₃Cl⁺ the global minimum is a linear singlet species, the singlet cyclic isomer lying about 19 kcal mol⁻¹ higher. The ionization potentials of cyclic and open-chain C₃Cl are estimated to be 9.17 and 8.21 eV, respectively, suggesting that these species should be easily ionized if present in the interstellar medium.     

Phase-Transfer Catalysis in Alkaline Hydrolysis of N-Benzyloxycarbonylglycine 4-Nitrophenyl Ester in the Two-Phase System Chloroform-Borate Buffer

Alkaline hydrolysis of N-benzyloxycarbonylglycine 4-nitrophenyl ester in the two-phase system chloroform-borate buffer (pH 10 and 11) in the presence of C₁₆H₃₃NMe₃Br and Ph₄PZ (Z = Cl, Br, I) at 25°C follows the extraction mechanism where the rate-determining stage is the chemical reaction in the organic phase. The different kinetic profiles of the reaction depending on the nature of Z^- were explained in terms of concurrent extraction of three kinds of anions: nucleophile OH^-, nucleofuge 4-NO₂C₆H₄O^-, and foreign ion Z^-.     

<Superscript>35</Superscript>Cl NQR for the SbCl<Subscript>3</Subscript> complex with aniline,SbCl<Subscript>3</Subscript>·NH<Subscript>2</Subscript>C<Subscript>6</Subscript>H<Subscript>5</Subscript>

The temperature dependence of the ³⁵Cl NQR frequencies and spin-lattice relaxation times has been investigated for a trigonal-bipyramidal vn complex SbCl₃·NH₂C₆H₅. Thermally activated motion of chlorine atoms (pseudorotation) was not revealed in the complex, in contrast to the vπ complexes of SbCl₃ with related molecular structures. The high potential barrier of pseudorotation in the aniline complex is likely to be due to the unusually high nonequivalence of Sb-Cl chemical bonds.     

Icosidodecahedral Coordination-Saturated Cuprofullerene

The first coordination-saturated buckyball with a C₆₀ molecule totally encased in an icosidodecahedral Cu₃₀ in a (μ₃₀-(η²)₃₀)-fashion, namely C₆₀@Cu₃₀@Cl₃₆N₁₂, has been successfully realized by a C₆₀-templated assembly. The 48 outmost coordinating atoms (36Cl+12N) comprise a new simple polyhedron that is described by a ccf topology. Charge transfer from (Cu^I, Cl) to C₆₀ explains the expansion of the light absorption up to 700 nm, and accounts for an ultrafast photophysical process that underpins its high photothermal conversion efficiency. This work makes a giant step forward in exohedral metallofullerene (ExMF) chemistry.     

Measurement of <Superscript>36</Superscript>Cl in nuclear wastes and effluents: Validation of a radiochemical protocol with an in-house reference sample

Summary ³⁶Cl is a beta-emitter with a very low specific activity. It is produced during the irradiation of nuclear fuel, in the reactor core of power plants, from neutron capture by stable ³⁵Cl that may be present at trace level in any part of the irradiated material. Due to its long half-life (T_1/2 = 3.01 ^. 10⁵ y), ³⁶Cl may be significant in impact assessment studies of disposal sites of nuclear wastes. Considering these different elements, the National Radioactive Waste Management Agency (Andra-France) requests information on the ³⁶Cl content of the waste packages destined to be stored at Andra sites. As for other halogens, the measurement of ³⁶Cl is a difficult analytical task in view of its potential losses during the different chemical steps and also because of the lack of international certified reference material needed to validate the chemical and measurement procedures. This paper describes the methodology processed to constitute an in-house solid reference sample with a known content of stable and radioactive chlorine. The original radiochemistry developed to extract ³⁶Cl from solid samples and purify it before a liquid scintillation counting is explained. The comparison of the results given by this radiochemical protocol and other methods allow its validation. The replication of the measurements on the constituted reference materials gives a repeatability around 8% at a confidence level of 95% that is very close to the calculated combined uncertainty value.     

Extent of exchange of36Cl with CAB in strong acid medium

Aqueous chloramine-B /C₆H₅SO₂NCl Na/ solution is known to contain species like RNCl^–, RNHCl, RNCl₂, RN⁺H₂Cl, HOCl and H²⁺OCl where R=C₆H₅SO₂. The exchange studies between³⁶Cl and CAB carried out in various media by ion-exchange method indicated that there is no exchange in solution at pH7. As the pH is decreased below 7, the extent of exchange increases reaching a maximum at pH 3. 3. The exchange decreases as the acidity is increased between pH 3.3 and 1N and again the exchange increases beyong 1N. The observed increase in exchange in strong acid medium is due to the evolution of chlorine.     

水热条件下金红石纳米晶在离子液体[C12mim]Cl中的制备

在室温离子液体1-十二烷基-3-甲基氯化咪唑([C12mim]Cl)中,通过水热法制备了具有单晶结构的金红石纳米材料。采用X射线衍射、扫描电镜和透射电镜对样品进行了表征,结果显示所得样品为纯金红石相,形貌呈棒状。扫描电镜和透射电镜图样显示金红石纳米棒的直径约为15 nm,长度在10～100 nm之间。高分辨投射电镜图样显示金红石纳米棒为单晶结构,并沿c轴方向生长。实验结果表明离子液体[C12mim]Cl中的Cl-有利于金红石相生成,[C12mim]+起到了模板剂的作用并提高了金红石纳米棒的结晶度。     

Displacement of dienes from planar complexes Reaction of (1,2-bisdiphenylphosphinoethane)(3a,4,7,7a-tetrahydro-exo-6-methoxy-endo-4,7-methanoindene-endo-5τ,2π)-palladium(II) and -platinum(II) cations with acids

A kinetic study of the reaction of [M(C₁₀H₁₂ · OCH₃)(P)]⁺ complexes (M = Pd, Pt; PP = 1,2-bisdiphenylphosphinoethane; C₁₀H₁₂ = endo-dicyclopentadiene) with hydrogen halides, HX (X = Cl, Br) in aqueous methanol at 35° C is described. The proposed mechanism involves slow formation of the solvato species [M(C₁₀H₁₂)(solv.)(P)]²⁺ followed by fast reaction with X^- to give M(PP)X₂.     

Theoretical study of the thermochemistry and the kinetics of the SFxCl (x = 0-5) series

A systematic thermodynamic and kinetic study of the entire SF_xCl (x = 0-5) series has been carried out. High-level quantum chemical composite methods have been employed to derive enthalpy of formation values from calculated atomization and isodesmic energies. The resulting values for the SCl, SFCl, SF₂Cl(C₁), SF₃Cl(C_s), SF₄Cl(C_s) and SF₅Cl molecules are 28.0, −36.0, −64.2, −134.3, −158.2 and −237.1 kcal mol⁻¹. A comparison with previous experimental and theoretical values is presented. Statistical adiabatic channel model/classical trajectory, SACM/CT, calculations of selected complex-forming and recombination reactions of F and Cl atoms with radicals of the series have been performed between 200 and 500 K. The reported rate coefficients span over the normal range of about 6 × 10⁻¹² and 5 × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ expected for this type of barrierless reactions.     

Mechanistic Aspects of the Gas‐Phase Reactions of Halobenzenes with Bare Lanthanide Cations: A Combined Experimental/Theoretical Investigation

The gas‐phase reactions of chlorobenzene with all atomic lanthanide cations Ln⁺ (except Pm⁺) have been investigated by using Fourier transform ion cyclotron resonance mass spectrometry in conjunction with density functional theory calculations. According to the latter, a direct chlorine transfer to the lanthanide cation, which has been observed previously for fluorine abstraction from fluorobenzene, is not operative for the C₆H₅Cl/Ln⁺ couples; rather, chlorine transfer proceeds through an initial coordination of the lanthanide cation to the aromatic ring of the substrate. Both, the product distribution and the chlorine abstraction efficiencies are affected by the bond dissociation energy (BDE(Ln⁺?Cl)) as well as the promotion energies of Ln⁺ to attain a 4fⁿ 5d¹ 6s¹ configuration. In addition, mechanistic aspects of some C?H and C?C bond activations are presented. Where appropriate, comparison with the previously studied C₆H₅F/Ln⁺ systems is made.     

Potential of lichens for monitoring iodine-129 and chlorine-36

Chlorine-36 (half life 3.01 × 10⁵ year), a beta emitter, is produced naturally but its presence has been enhanced by atmospheric weapons testing and other nuclear activities. Iodine-129 has a half life of 1.57 × 10⁷ years and is also produced by nuclear activities, in particular fuel reprocessing. Many elements have a long biological half-life in lichens, which were thus investigated so as to assess their suitability for ³⁶Cl and ¹²⁹I monitoring. Lichens sampled between 1998 and 2008 were analysed for total chlorine, and selected samples were processed for ³⁶Cl measurement using Accelerator Mass Spectrometry (AMS); ¹²⁹I was analyzed by gamma spectrometry. Different aspects are discussed: long-term storage in lichens versus environmental mobility, levels in samples collected near a reprocessing facility, and potential for spatial and temporal monitoring.     

242Pu as tracer for simultaneous determination of 237Np and 239,240Pu in environmental samples

A procedure has been developed using ²⁴²Pu as tracer for simultaneous determination of ²³⁷Np and ^239,240Pu in environmental samples. The validity of the method has been demonstrated by ICPMS and a-spectroscopy for up to 10 gram soil and sediment, seawater up to 200 litres. The paper describes a suitable chemical procedure for Np and Pu including a quantitative pre-concentration of neptunium and plutonium, preparation of Np⁴⁺ and Pu⁴⁺, Np(NO₃)₆ ^2- and Pu(NO₃)₆ ^2-. The ratio of ²³⁷Np/²⁴²Pu (or ²³⁷Np/²³⁹Pu) before and after the procedure has been determined using 10 g soil (free from Np and Pu) R _before/R _after = 1.004±3.3% (S.D n = 20) and 1 litre seawater R _before/R _after = 1.019±1.9% (S.D., n = 12). Results from the intercomparison samples IAEA-135, IAEA-381 and from environmental samples are presented.     

Measurements of the apparent rate constant for the reaction of iodine monoxide with chlorine monoxide to form iodine atoms

An apparatus for measuring the resonance fluorescence signals of iodine and chlorine atoms is constructed to study iodine monoxide reaction with chlorine monoxide. A technique using the reaction of chlorine atoms with C₂H₆ is developed to calibrate the sensitivity of the apparatus to chlorine atoms. The apparent rate constants for the reaction between 10^• and CIO^• radicals producing iodine atoms was measured at 295 K k_app = (2.62 ± 0.57) x 10-^-11 cm³ molecule^-1 s^-1.     

The microwave spectrum,structure and centrifugal distortion constants of 2-chloroacrylonitrile

The microwave spectrum of 2-chloroacrylonitrile has been studied in the 26.5–40 GHz region. A total of 99 a- and b-type rotational transitions have been measured and assigned for CH₂ =C³⁵Cl(CN),yielding values for the rotational constants (in MHz): A = 6973.27, B = 3148.16, C = 2165.95. For CH₂=C³⁷Cl(CN) a total of 53 transitions have been measured and assigned and the rotational constants obtained are (in MHz): A = 6909.35, B = 3081.17, C = 2127.98. The distortion effects have also been studied and the quartic distortion constants have been evaluated. From the observed hyperfine structure, the chlorine nuclear quadrupole coupling constants have been obtained. The structure of vinyl cyanide and vinyl chloride can be transferred to account remarkably well for the observed rotational constants.     

Oxidation of coordinated olefins: the reactions of Cl2 with trichloro(ehtylene)platinate(II)

The oxidation of [PtCl₃(C₂H₄)]- by Cl₂ in aqueous solution, to yield CH₂ClCH₂OH and [PtCl₄]^2-, has been shown to proceed through the following sequence of steps: [PtCl₃(C₂H₄)] Cl₂Cl [PtCl₅(CH₂CH₂Cl)]^2-$\text{H}{}_2\text{O}\text{(HCl)}$ [PtCl₅(CH₂CH₂OH)]^2- → [PtCl₄^2- + CH₂ClCH₂OHEach of the steps and intermediates in this mechanistic sequence has been identified and characterized.     

Characterization of an extraction chromatographic resin for the separation and determination of 36Cl and 129I

The monitoring of long-lived radionuclides is of great importance in the context of the surveillance of nuclear facilities, during their operation as well as during their decommissioning. This is especially true for radionuclides of rather volatile elements, such as chlorine and iodine, the main interest being in ³⁶Cl and ¹²⁹I. Liquid Scintillation Counting (LSC) is a widely used measurement technique especially for the determination of ³⁶Cl that requires a thorough and selective sample preparation in order to give accurate results. Sample preparation methods frequently employed such as volatilization and/or repeated precipitation steps can be rather elaborate and time consuming. Therefore, an attempt has been made to develop an ‘easy to use’ extraction chromatographic resin that allows extraction, and subsequent separation, of chloride and iodide from pretreated environmental and decommissioning samples for their determination via LSC. First results of the characterization of the resin including D _w values of Cl^?, I^? and potential interferents, and of the method development are presented as well as the result of the analysis of a simulated real sample.     

High-field solid-state <Superscript>35</Superscript>Cl NMR in selenium(IV) and tellurium(IV) hexachlorides

We report solid-state ³⁵Cl NMR spectra in three hexachlorides, (NH₄)₂SeCl₆, (NH₄)₂TeCl₆ and Rb₂TeCl₆. The C_Q(³⁵Cl) quadrupole coupling constants in the three compounds were found to be 41.4±0.1 MHz, 30.3±0.1 MHz and 30.3±0.1 MHz, respectively, some of the largest C_Q(³⁵Cl) quadrupole coupling constants ever measured in polycrystalline powdered solids directly via ³⁵Cl NMR spectroscopy. The ³⁵Cl EFG tensors are axial in all three cases reflecting the C_4v point group symmetry of the chlorine sites. ³⁵Cl NMR experiments in these compounds were only made possible by employing the WURST-QCPMG pulse sequence in the ultrahigh magnetic field of 21.1 T. ³⁵Cl NMR results agree with the earlier reported ³⁵Cl NQR values and with the complementary plane-wave DFT calculations. The origin of the very large C_Q(³⁵Cl) quadrupole coupling constants in these and other main-group chlorides lies in the covalent-type chlorine bonding. The ionic bonding in the ionic chlorides results in significantly reduced C_Q(³⁵Cl) values as illustrated with triphenyltellurium chloride Ph₃TeCl. The high sensitivity of ³⁵Cl NMR to the chlorine coordination environment is demonstrated using tetrachlorohydroxotellurate hydrate K[TeCl₄(OH)]?0.5H₂O as an example. ¹²⁵Te MAS NMR experiments were performed for tellurium compounds to support ³⁵Cl NMR findings.     

Trace analysis of chlorine in high-purity refractory metals with isotope dilution mass spectrometry

Summary A method for the determination of chlorine in high-purity molybdenum and tungsten with isotope dilution mass spectrometry (IDMS) has been developed using a ³⁷Cl enriched spike solution. After dissolution of the sample in H₂O₂, chlorine is separated by AgCl precipitation. Negative Cl^- thermal ions are produced in a double-filament ion source using an easy-to-handle and cost-efficient quadrupole thermal ionization mass spectrometer. The detection limit, which is mainly influenced by contaminations from the laboratory air, lies between 0.006 and 0.1 g/g depending on the variation of the blank values. Chlorine concentrations between 0.07 and 10.5 g/g are analysed in different tungsten and molybdenum samples. A comparison with other sensitive analytical methods shows the urgent necessity of developing alternative methods for the determination of chlorine traces in refractory metals.Dedicated to Professor Dr. V. Krivan on the occasion of his 60th birthday     

Kinetics of the liquid-phase chlorination of allyl chloride in a nonpolar solvent

The kinetics and mechanism of the chlorination of C₃H₅Cl were studied in a broad interval of temperatures and reactant concentrations. Competition was found between homolytic and nonradical chlorination of C₃H₅Cl in liquid phase in a nonpolar solvent. It was shown that for [C₃H₅Cl] < 0.1 M and T < 270 K the main reaction is the nonradical reaction, which has a negative temperature coefficient. The kinetics of the nonradical chlorination of C₃H₅Cl is dependent on the concentration of chlorine and is described by the sum of kinetic reactions of overall second and third orders. If [Cl₂] > 1.5 M the main reaction is the reaction involving two molecules of chlorine and one molecule of olefin.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 2, pp. 155–158, March–April, 1992.