- New topology in azide-bridged cobalt(11) complexes: The weak ferromagnet [Co2(N3)4(HexamethylenetetramineKH 2O)]n
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A new polynuclear azido-bridged Co(11) compound with formula [Co 2(N3)4(HMTA)(H2O)]n (1) (HMTA = hexamethyl-enetetramine) has been structurally and magnetically characterized. The compound 1 crystalli
- Mautner, Franz A.,Oehrstroem, Lars,Sodin, Beate,Vicente, Ramon
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- The rates of the elementary reactions of NH(a1 Δ) with NH3(X) and HN3(X). The temperature dependences
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The reactions NH(a) + HN3(X) → prod. (1) and NH(a) + NH3(X) → prod. (2) were studied in a quasi-static reaction cell in the temperature range 293 ≤ T/K ≤ 501 at a pressure of 10 mbar and 20 mbar, respectively, with He as the main carrier gas. The electronically excited reactant NH(a) was generated by laser-flash photolysis of HN 3, at λ = 308 nm and detected by laser-induced fluorescence (LIF). Also the ground state species NH(X) was detected by LIF. From the measured concentration-time profiles of NH(a) under pseudo-first order conditions, the rate coefficients k1(T) and k2(T) were obtained. For the rate coefficient k1 a positive temperature dependence was observed: k1(T) = (8.1 ± 0.5) × 10 13 exp[(-0.76 ± 0.05)/RT] cm3/mol s with a small activation energy of EA = 0.76 kJ/mol. For reaction (2) the rate coefficient k2(T) = (8.6 ± 0.6) × 1013 (T/298)-(0.6±0.1) cm3/mol s with a negative temperature dependence was measured indicating that the intermediate N 2H4, which decomposes to 2NH2, is formed without a barrier. The rate of the quenching channel NH(a) + NH3 → NH(X) + NH3 (2q) has the same temperature dependence as the rate of the overall reaction (2). The contribution k2q/k2 = 0.008 over the temperature range 293 ≤ T/K ≤ 501.
- Adam,Hack,Olzmann
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- Mechanism of the Reaction of NH(1Δ) with NO in Argon Matrix
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Matrix-isolated hydrazoic acid HN3 admixed with NO was photolyzed by a low-pressure mercury discharge lamp.Product analysis based on the FTIR spectroscopy has revealed the formations of NH, N2O, OH, HNO, and HONO as photoproducts.From the comparisons of the amount of HN3 consumed with that of N2O produced, we conclude that the reaction of NH(1Δ) with NO proceeds mainly through the process NH(1Δ)+NON2O+H.The quantum yield of N2O is found to be Φ1=0.7+/-0.1.The conclusion is in line with our previous results of the gas phase experiments at room temperature.
- Yokoyama, Keiichi,Kitaike, Hiroshi,Fueno, Takayuki
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- Collision-Induced Intersystem Crossing of NH(a1Δ, v''= 0.1) by N2 and Xe: Temperature Dependence (N2) and Product States (N2, Xe)
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The elementary reactions of NM(a1Δ,v''=0) with N2 and Xe have been studied in the gas phase.NH(a,v'') was produced by laser photolysis of HN3 at λl = 248 nm and λL = 308 nm and detected directly by laser-induced fluorescence (LIF) via the c1Π-a1Δ) transition.Time resolution is based on the delay between the photolysis and the probe laser.The reaction rates were determined under pseudo-first-order conditions ( >>a,v'')>0), at different temperatures in the range 290 a,v''=0) + N2 -> products (1), k1 = (3.9 +/- 1.2) * 1011 exp(-(5.4 +/- 1.2) kJ mol-1/RT)cm3/(mol s); NH(a,v''=1) + N2 -> products (2), k2 = (8.6 +/- 2.7) * 1011 exp(-(4.4+/- 2.3) kJ mol-1/RT) cm3/(mol s); ND(a,v''=0) + N2 -> products (3), k3 = (4.7 +/- 1.7) * 1011 exp(-(5.2 +/- 1.1) kJ mol-1/RT) cm3/(mol s).The NH(X,v), which appeared as the product of physical quenching, was detected by LIF with the transition (A3Π-X3Σ-).In the reaction 1, 2, and 3 NH(X) and ND(X), respectively, were formed only in the vibrational ground state.The rate constant for the process NH(a,v''=1) + Xe -> products (5) was determined to be k5 = (7.7 +/- 0.9) * 1012 cm3/(mol s).In the physical quenching of NH(a,v'') (produced at λL = 248 nm) by Xe vibrationally vibrationally excited NH in the electronic ground sate NH(X,v=0,1,2) was detected NH(a,v''=0) (produced at λL = 308 nm) was quenched to NH(X,v=0).The different quenching dynamics of NH(a,v'') by N2 and Xe are discussed.
- Hack, W.,Rathmann, K.
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- Phenylborylene: Direct spectroscopic characterization in inert gas matrices
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The photolysis of bisazidophenylborane isolated in cryogenic matrices results in phenylborylene, a subvalent boron(I) species with a singlet ground state. Broad band irradiation of phenylborylene causes formation of benzoborirene by insertion into an ortho-CH bond. Copyright
- Bettinger, Holger F.
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- Epitaxial growth of inn films by molecular-beam epitaxy using hydrazoic acid (HN3) as an efficient nitrogen source
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Epitaxial InN films have been successfully grown on c-plane GaN template by gas-source molecular-beam epitaxy with hydrazoic acid (HN3) as an efficient nitrogen source. Results in residual-gas analyzer show that the HN3 is highly dissociated to produce nitrogen radicals and can be controlled in the amounts of active nitrogen species by tuning HN3 pressure. A flat and high-purity InN epifilm has been realized at the temperature near 550 °C, and a growth rate of 200 nm/hr is also achieved. Moreover, the epitaxial relationship of the InN(002) on the GaN(002) is reflected in the X-ray diffraction, and the full-width at half-maximum of the InN(002) peak as narrow as 0.05° is related to a high-quality crystallinity. An infrared photoluminescence (PL) emission peak at 0.705 eV and the integrated intensity increasing linearly with excitation power suggest that the observed PL can be attributed to a free-to-bound recombination.
- Chen,Hsiao,Hsu,Wu,Yen,Wei,Chen,Chen
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- 3D azido-bridged cobalt(II) complexes with diazines as coligands
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Two new three-dimensional azido-bridged Co(II) compounds with formula [Co(N3)2(2,5-Me2pyz)]n (1) and [Co(N3)2(2-ampym)]n (2) have been structurally and magnetically characterized
- Mautner, Franz A.,Sodin, Beate,Vicente, Ramon
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- A new energy transfer chemical laser at 1.315 μm
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CW laser action has been demonstrated on the electronic I*(2P1/2)→I(2P 3/2) transition of atomic iodine at 1.315 μm from the NCl (a1Δ)+I(2P 3/2) energy transfer reaction. The stimulated emission was generated in a transverse subsonic flow device when hydrogen azide, HN3, was injected into a flow of iodine and chlorine atoms. The measured laser output power was 180 mW.
- Henshaw, Thomas L.,Manke Ii, Gerald C.,Madden, Timothy J.,Berman, Michael R.,Hager, Gordon D.
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- Temperature dependence of the UPS and HREELS of HN3 and DN3 on Si(110)
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HN3 was used for the first time as a nitrogen source for nitridation of Si surfaces. Its interaction with Si(110) was studied with HREELS and UPS at temperatures between 120 and 1350 K. HN3 was found to adsorb molecularly on the Si surface at 120 K, as all molecular vibrational peaks, such as HN-NN stretching at 150 meV, HNN=N stretching at 265 meV and H-NNN stretching at 414 meV, were clearly observed in HREEL spectra. A similar HREELS study of DN3 was carried out to confirm some of the EELS assignments. Upon warming up to 220 K, HN3 started to dissociate into N2 and NH, which further dissociated to give N and H as the surface was annealed from 580 to 800 K, H adatoms were observed to desorb at T > 800 K, while N remained on the surface, forming Si3N4 at T ? 1350 K.
- Bu,Chu,Lin
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p. L151 - L156,L151-L156
(1992)
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- Binary Zinc Azides
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Pure, solvent-free Zn(N3)2 was prepared by reaction of diethyl zinc and hydrazoic acid in aprotic solvents. The single-crystal structure determination, along with the comprehensive characterization of α-Zn(N3)2 and two metastable polymorphs, could be achieved for the first time. Since these data disagree in large parts with the known, previously reported values, all previous syntheses of Zn(N3)2, and for comparison Zn(N3)2×2.5 H2O and Zn(OH)N3 were reinvestigated, indicating that some of the earlier work has to be revised.
- Schulz, Axel,Villinger, Alexander
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- Synthesis of Al(N3)3 and the deposition of AlN thin films
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Al(N3)3 is produced by the stoichiometric reaction between Al(CH3)3 and excess HN3 at room temperature. The reaction is thought to proceed by the addition of HN3 to Al(CH3)3 followed by elimination of CH4, repeated three times to produce the fully azidified Al(N3)3. The product Al(N3)3 is nonvolatile and condenses as a film on the walls of the reaction vessel. The reaction products were observed in the gas phase and in low-temperature argon matrices by FTIR spectroscopy. Ab initio methods were used to compute the geometry and frequencies of Al(N3)3, and the results are in good agreement with experimental data. The films produced upon condensation of Al(N3)3 contain the Al-N2 complex and AlN as well as the azide. Heating the films to 400 K removes the azide and the Al-N2, leaving AlN. This method may be useful as a low-temperature route to the synthesis of AlN thin films.
- Linnen,Macks,Coombe
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- Mechanism of the photochemically induced reaction between Ga(CH3)3 and HN3 and the deposition of GaN films
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Gaseous HN3 reacts with surface-bound Ga(CH3)x species slowly at 300 K to produce thin films containing azide-substituted gallium compounds. When mixtures of HN3 and Ga(CH3)3 over the surfa
- Linnen,Coombe
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- Identification of a surface azide from the reaction of HN3 with C(100)
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The reaction of hydrogen azide, HN3, with bare and hydrogenated diamond (100) was studied using high resolution electron energy loss spectroscopy (HREELS). Hydrogen azide adsorbs molecularly on the hydrogenated diamond surface at 100 K and desorbs without reacting at 3 reacts with C(100) at 100 K by breaking the N-H bond to form C-N3 and C-H surface species. The breaking of the N-H bond is in contrast to the reaction mechanism of HN3 on Si and Ge surfaces in which breaking of the HN-NN bond is observed. We suggest that the stronger bonding of hydrogen to the diamond surface is responsible.
- Thoms,Russell Jr.
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p. L807 - L811,L807-L811
(1995)
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- Ladders, rings and cubes as structural motifs in three new zinc(II) azide complexes: Synthesis, spectral and structural characterization
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Three new zinc(II) azide complexes, namely {[Zn2(N3)4(py-tetrazole)2](py-tetrazole)}n (1), {[Zn2(N3)4(3-OHpy)] · 2H2O}n (2) and [Zn(N3)2(pym)]n (3), where py-tetrazole = tetrazolo[1,5-a]pyridine, 3-OHpy = 3-hydroxypyridine and pym = pyrimidine, have been synthesized by the hydrothermal methods and structurally characterized. The ligand py-tetrazole was obtained through the interaction of 2-chloropyridine with the azide ion under hydrothermal condition. The structure of 1 consists of a ladder-like arrangement of 1D double chain zinc(II) azide. In the coordination chain, each zinc atom binds di-EO azide bridges connecting another zinc atom in opposite chain, and two EO bridges, one on each side, and the fifth position is occupied by a N atom of py-tetrazole ligand. The structure of 2 features 2D sheets composed of tetranuclear zinc(II) ring and octanuclear zinc(II) ring interconnected by EO azide bridges. The 2D carrying into 3D supramolecular network by the help of several hydrogen bonding interactions. The 3-OHpy molecule acts in the tautomeric keto-form as O,O-bidentate bridging ligand. Complex 3 features distorted octahedral geometry around each zinc center, N,N′-bidentate pyrimidine ligand and EE azido bridges leading to 3D network structure. The IR spectra are measured and discussed. Complex 2 only exhibits photoluminescence properties whereas the other two complexes do not luminesce at room temperature.
- Goher, Mohamed A.S.,Sodin, Beate,Bitschnau, Brigitte,Fuchs, Elmar C.,Mautner, Franz A.
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- Photodissociation dynamics of HN3 and DN3 at 157 nm
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Photodissociation dynamics of HN3 at 157.6 nm have been studied using the H-atom Rydberg tagging timeof-flight technique. Product translational energy distributions and angular distributions have been measured. From these distributions, three H-atom channels are observed. The vibrational structure in the fast-H channel could be assigned to a progression in the N3 symmetric stretching mode (v100), together with a progression of the symmetric stretching mode with one quantum of bending motion (V110). The broad translational energy distribution of the slow-H channel is energetically consistent with the cyclic-N3 formation process or a triple product dissociation channel. Photodissociation of DN3 was also investigated using the same technique. Isotope effect on the product translational energy distribution has been observed, in which the slow H-atom is clearly more pronounced.
- Yuan, Kaijun,Cheng, Yuan,Wang, Fengyan,Yang, Xueming
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- Photodecomposition and photooxidation of hydrogen sulfite in aqueous solution
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A zinc arc lamp and a mercury lamp, respectively, were used to study the photodecomposition of HSO3- and SO32- in aqueous solutions saturated with either argon or nitrous oxide. The main products in both cases were sulfate and dithionate, which are attributed to arise from the self-reaction of SO3- radicals. Quantum yields for the formation of SO3- in argon-saturated solution based on hydrazoic acid and/or ferric oxalate actinometry were 0.19 ± 0.03 for HSO3- and 0.39 ± 0.03 for SO32-, essentially independent of S(IV) concentration. In both systems, the rate of sulfate formation rose with time at the expense of that of dithionate. This is explained by reactions of hydrogen atoms and hydrated electrons with dithionate (rate coefficient k5 ≈ 2 × 105 dm3 mol-1 s-1). N2O as a scavenger for these radicals removed the effect and raised the quantum yields to 0.25 ± 0.03 and 0.75 ± 0.04, respectively. The product ratios under these conditions were [S2O62-]/ [SO42-] = 0.43 ± 0.04 for HSO3- and 0.61 ± 0.03 for SO32-. In oxygen-saturated solutions, the photolysis of HSO3- led to a short chain reaction with sulfate and peroxodisulfate as products. The latter product was assigned to arise from the recombination of SO5- radicals. Steady state analysis of the product evolution with time gave rate coefficients for two of the reactions involved: k16(SO5- + HSO3-) = (1.2 ± 0.4) × 104 dm3 mol-1 s-1 for the main propagation reaction and k19a(HO2 + SO5-) = (1.8 ± 1.0) × 109 dm3 mol-1 s-1 for the principal termination reaction. These values agree well with recent data from radiolysis experiments.
- Fischer, Michael,Warneck, Peter
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- Synthesis and structural characterization of three new 1D and 2D zinc(II) azide polymers with some pyridine and pyrazine derivative ligands
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Three new polymeric zinc(II) azido complexes, namely [Zn(N3)2(3-Brpy)]n (1), [Zn(N3)2(4-Etpy)]n (2) and [Zn2(N3)4(2,5-dmpyz)]n (3), where Brpy = bromopyridine, Etpy = ethylpyridine and dmpyz = dimethylpyrazine have been prepared and structurally characterized. The IR spectra of these complexes are measured and discussed. The structures of 1 and 2 are similar and feature one-dimensional zigzag chain of [Zn(N3)2]n in which each zinc atom is surrounded by double di-end on (EO) bridging azido ligands forming cyclic Zn2N2 units. Furthermore, each zinc atom links a N hetero atom of the pyridine moiety leading to ZnN5 chromophore. The geometry around the zinc center is best described as distorted trigonal bipyramid. Although complex 3 consists of the 1D chain of [Zn(N3)2]n with double di-EO azido bridges around each zinc center with almost planar Zn2N2 cyclic units, the pyrazinic moiety behaves as a bidentate bridging N,N′-ligand that binds the zinc centers across the [Zn2(N3)2]n chains extending the structure to be two-dimensional sheets. The Zn ... Zn distances within the Zn2N2 units are similar, fall within the range of 3.20-3.26 ?, and the azido ligands are asymmetric and linear within experimental error in all of these three complexes.
- Goher, Mohamed A.S.,Bitschnau, Brigitte,Sodin, Beate,Gspan, Christian,Mautner, Franz A.
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- Complex-forming bimolecular reactions of metastable NH(a1Δ) with H2O(X?1a1) and H2O2(X?1A)
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The elementary reactions: NH(a1Δ) + H2O(X?) → products NH (a1Δ, v) + H2O2 (X?) → products were studied in a quasistatic laser photolysis cell at a pressure of 20 mbar in the temperature range 295 ≤ T/K ≤ 523 and at room temperature respectively. NH(a1Δ,v) was produced by excimer laser photolysis of HN3(X?) and detected by laser-induced fluorescence (LIF). A variable delay time between photolysis and detection pulse brought about the time resolution. The NH(a) depletion yielded the following rate constants: k1(T) = (3.5±0.8)1013(T/295 K)-(1.5±0.2) cm3/mol s k2(v = 0) = (7.5 ± 1.4) 1013 cm3/mol s k2(v= 1) = (7.1 ± 0.9)1013cm3/mol s The reaction products of reaction (1) are NH2(X?) + OH(X). For reaction (2) NH2(X?) radicals were detected (24%); the quenching channel was found to be unimportant kq11 cm3/mols. The reaction mechanism is discussed. The reaction NH(a) + H2O(X?) is compared to the reaction NH(X) + H2O(X?). VCH Verlagsgesellschaft mbH, 1997.
- Hack,Jordan
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- Highly energetic tetraazidoborate anion and boron triazide adducts
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The first crystal structures of the highly energetic tetraazidoborate anion and boron triazide adducts with quinoline and pyrazine as well as of tetramethylpiperidinium azide have been determined. Synthesis procedures and thorough characterization by spectroscopic methods of these hazardous materials are given. Quantum chemical calculations were carried out for B(N3)4-, B(N3)3, C5H5N·B(N3)3, (N3)3B·NC4H4N· B(N3)3, and the hypothetical C3H3N3· [B(N3)3]3 at HF, MP2, and B3-LYP levels of theory. The structure of tetraazidoborate was optimized to S4 symmetry and confirmed the results obtained from the X-ray diffraction analysis. The dissociation enthalpies for the pyridine (model for quinoline) as well as for the pyrazine adduct were calculated. For pyridine-boron triazide a value of 10.0 kcal mol-1 (for pyrazine-bis(boron triazide) an average of 2.35 kcal mol-1 per BN unit) was obtained.
- Fraenk,Habereder,Hammerl,Klapoetke,Krumm,Mayer,Noeth,Warchhold
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- The aminodiazonium cation, H2N3+
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The H2N3+ salts of SbF6-, AsF6-, and BF4- have been prepared and, for the first time, been isolated from HF solutions of HN3 and the corresponding Lewis acids. They are hygroscopic white solids which are stable at room temperature. The crystal structure of H2N3+SbF6- was determined at 20 K. This compound crystallizes in the orthorhombic system, space group Pmc21, with two molecules in a unit cell of dimensions a = 5.794 (3) ?, b = 5.113 (2) ?, and c = 9.919 (5) ? with R = 0.015, Rw = 0.022, for 587 observed [I > 3σ(I)] reflections. In addition to two almost perfectly octahedral SbF6- anions, the unit cell contains two asymmetric H2N3+ cations with N(1)-N(2) = 1.295 (5) ?, N(2)-N(3) = 1.101 (6) ?, and N(1)-N(2)-N(3) = 175.3 (5)° and both hydrogens bonded to the same nitrogen atom, N(1). The infrared and Raman spectra of these salts were also recorded. Local density functional calculations were carried out for H2N3+ and isoelectronic H2NCN and used for the assignment of the observed vibrational spectra and the determination of their force fields. The general agreement between the calculated and observed geometries and frequencies is very good. The results from the LDF calculations indicate that the H2N? group in H2N3+ is less pyramidal than that in H2NCN and, therefore, possesses a lower inversion energy barrier.
- Christe, Karl O.,Wilson, William W.,Dixon, David A.,Khan, Saeed I.,Bau, Robert,Metzenthin, Tobias,Lu, Roy
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- Preparation of a nanoscale homogeneous energetic lead azides?porous carbon hybrid with high ignition ability by: In situ synthesis
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The ever-increasing demand for miniaturized explosive systems urgently calls for better performance studies through the synthesis of novel nanoscale materials. In this work, lead azide?porous carbon hybrids (LA?PC) are synthesized by in situ carbonization and azidation of a lead-containing cross-linked gel, in which the nanoscale LA is uniformly distributed on the porous carbon skeleton. The detailed characterization has shown that such outstanding performance stems from the LA nanoscale effect and the excellent conductivity and thermal conductivity of carbon cages. Because of the favorable unique structure, the prepared composite material exhibits excellent ignition performance, and its flame sensitivity can reach 42 cm, which solves the problem of poor ignition capacity of LA on all occasions. In addition, the composite has very low electrostatic sensitivity, further improving the safety of practical application. This work makes it possible for LA to be detonated without using lead styphnate, paving a new way for improving the flame sensitivity of primary explosives.
- Han, Ji-Min,Liu, Jianchao,Song, Naimeng,Yan, Zhenzhan,Yang, Li
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- Engineered Regulon to Enable Autonomous Azide Ion Biosensing, Recombinant Protein Production, and in Vivo Glycoengineering
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Detection of azide-tagged biomolecules (e.g., azido sugars) inside living cells using "click"chemistry has been revolutionary to the field of chemical biology. However, we currently still lack suitable synthetic biology tools to autonomously and rapidly d
- Bandi, Chandra Kanth,Skalenko, Kyle S.,Agrawal, Ayushi,Sivaneri, Neelan,Thiry, Margaux,Chundawat, Shishir P. S.
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p. 682 - 689
(2021/05/07)
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- Design, synthesis and evaluation of carbamate-linked uridyl-based inhibitors of human ST6Gal I
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Sialic acid at the terminus of cell surface glycoconjugates is a critical element in cell-cell recognition, receptor binding and immune responses. Sialyltransferases (ST), the enzymes responsible for the biosynthesis of sialylated glycans are highly upregulated in cancer and the resulting hypersialylation of the tumour cell surface correlates strongly with tumour growth, metastasis and drug resistance. Inhibitors of human STs, in particular human ST6Gal I, are thus expected to be valuable chemical tools for the discovery of novel anticancer drugs. Herein, we report on the computationally-guided design and development of uridine-based inhibitors that replace the charged phosphodiester linker of known ST inhibitors with a neutral carbamate to improve pharmacokinetic properties and synthetic accessibility. A series of 24 carbamate-linked uridyl-based compounds were synthesised by coupling aryl and hetaryl α-hydroxyphosphonates with a 5′-amino-5′-deoxyuridine fragment. The inhibitory activities of the newly synthesised compounds against recombinant human ST6Gal I were determined using a luminescent microplate assay, and five promising inhibitors with Ki’s ranging from 1 to 20 μM were identified. These results show that carbamate-linked uridyl-based compounds are a potential new class of readily accessible, non-cytotoxic ST inhibitors to be further explored.
- Dobie, Christopher,Hallam, Laura,Montgomery, Andrew P.,Ranson, Marie,Skropeta, Danielle,Szabo, Rémi,Yu, Haibo
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- HIP to be Square: Simplifying Nitridophosphate Synthesis in a Hot Isostatic Press
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(Oxo)Nitridophosphates have recently been identified as a promising compound class for application in the field of solid-state lighting. Especially, the latest medium-pressure syntheses under ammonothermal conditions draw attention of the semiconductor and lighting industry on nitridophosphates. In this contribution, we introduce hot isostatic presses as a new type of medium-pressure synthetic tool, further simplifying nitridophosphate synthesis. In a second step, phosphorus nitride was replaced as starting material by red phosphorus, enabling the synthesis of Ca2PN3 as model compound, starting only from readily available compounds. Moreover, first luminescence investigations on Eu2+-doped samples reveal Ca2PN3:Eu2+ as a promising broad-band red-emitter (λem=650 nm; fwhm=1972 cm?1). Besides simple handling, the presented synthetic method offers access to large sample volumes, and the underlying reaction conditions facilitate single-crystal growth, required for excellent optical properties.
- Mardazad, Sara,Schmidt, Peter J.,Schnick, Wolfgang,Strobel, Philipp,Wendl, Sebastian
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supporting information
p. 18240 - 18243
(2020/08/21)
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- Trapping of Br?nsted acids with a phosphorus-centered biradicaloid - synthesis of hydrogen pseudohalide addition products
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The trapping of classical hydrogen pseudohalides (HX, X = pseudohalogen = CN, N3, NCO, NCS, and PCO) utilizing a phosphorus-centered cyclic biradicaloid, [P(μ-NTer)]2, is reported. These formal Br?nsted acids were generatedin situas gases and passed over the trapping reagent, the biradicaloid [P(μ-NTer)]2, leading to the formation of the addition product [HP(μ-NTer)2PX] (successful for X = CN, N3, and NCO). In addition to this direct addition reaction, a two-step procedure was also applied because we failed in isolating HPCO and HNCS addition products. This two-step process comprises the generation and isolation of the highly reactive [HP(μ-NTer)2PX]+cation as a [B(C6F5)4]?salt, followed by salt metathesis with salts such as [cat]X (cat = PPh4,n-Bu3NMe), which also gives the desired [HP(μ-NTer)2PX] product, with the exception of the reaction with the PCO?salt. In this case, proton migration was observed, finally affording the formation of a [3.1.1]-hetero-propellane-type cage compound, an OC(H)P isomer of a HPCO adduct. All discussed species were fully characterized.
- Beer, Henrik,Bl?sing, Kevin,Bresien, Jonas,Chojetzki, Lukas,Schulz, Axel,Stoer, Philip,Villinger, Alexander
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supporting information
p. 13655 - 13662
(2020/10/27)
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- A novel Pt(iv) mono azido mono triazolato complex evolves azidyl radicals following irradiation with visible light
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The platinum(iv) azido complex trans,trans,trans-[PtIV(N3)2(OH)2(py)2] (1) undergoes cycloaddition with 1,4-diphenyl-2-butyne-1,4-dione (2) under mild, catalyst-free conditions, affording a number of mono and bis click products. The major mono click product (3) exists in MeCN as an equilibrium mixture between two species; 3a and 3b rapidly interconvert through nucleophilic attack of the axial Pt-OH group at the adjacent Ph-CO group. The kinetic and thermodynamic parameters for this interconversion have been measured by selective saturation-transfer NMR spectroscopic experiments and are consistent with cyclisation at the Pt centre. Complex 3b was also characterised by X-ray crystallography. Visible light irradiation (440-480 nm) of 3 in d3-MeCN produces azidyl radicals (N3), as demonstrated by EPR spin-trapping with DMPO; no generation of hydroxyl radicals was observed. 1H-195Pt HMBC NMR confirmed that the photoproducts were PtIV rather than PtII species, and HPLC was consistent with these being [3-N3]+ species; no facile photoejection of the triazolato ligand was observed, consistent with MS/MS fragmentation of 3. When 3 was irradiated in the presence of 5′-GMP, no 5′-GMP photoproducts were observed, suggesting that complex 3 is likely to exhibit significantly simplified biological activity (release of azidyl radicals but not DNA binding) compared with complex 1.
- Yao, Kezi,Bertran, Arnau,Morgan, Jacques,Hare, Samuel M.,Rees, Nicholas H.,Kenwright, Alan M.,Edkins, Katharina,Bowen, Alice M.,Farrer, Nicola J.
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supporting information
p. 6416 - 6420
(2019/05/24)
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- Study on the degradation mechanism and pathway of benzene dye intermediate 4-methoxy-2-nitroaniline: Via multiple methods in Fenton oxidation process
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Benzene dye intermediate (BDI) 4-methoxy-2-nitroaniline (4M2NA) wastewater has caused significant environmental concern due to its strong toxicity and potential carcinogenic effects. Reports concerning the degradation of 4M2NA by advanced oxidation process are limited. In this study, 4M2NA degradation by Fenton oxidation has been studied to obtain more insights into the reaction mechanism involved in the oxidation of 4M2NA. Results showed that when the 4M2NA (100 mg L-1) was completely decomposed, the TOC removal efficiency was only 30.70-31.54%, suggesting that some by-products highly recalcitrant to the Fenton oxidation were produced. UV-Vis spectra analysis based on Gauss peak fitting, HPLC analysis combined with two-dimensional correlation spectroscopy and GC-MS detection were carried out to clarify the degradation mechanism and pathway of 4M2NA. A total of nineteen reaction intermediates were identified and two possible degradation pathways were illustrated. Theoretical TOC calculated based on the concentration of oxalic acid, acetic acid, formic acid, and 4M2NA in the degradation process was nearly 94.41-97.11% of the measured TOC, indicating that the oxalic acid, acetic acid and formic acid were the main products. Finally, the predominant degradation pathway was proposed. These results could provide significant information to better understand the degradation mechanism of 4M2NA.
- Guo, Ying,Xue, Qiang,Cui, Kangping,Zhang, Jia,Wang, Hui,Zhang, Huanzhen,Yuan, Fang,Chen, Honghan
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p. 10764 - 10775
(2018/03/26)
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- NITRIC OXIDE-RELEASING PRODRUG MOLECULE
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Provided are a type of compounds that can be used for treating cardiovascular diseases and compositions containing the compounds. The compounds and the compositions can improve lipid metabolism disorders by increasing high-density lipoprotein cholesterol in blood; in addition, the compounds and the compositions can also release nitric oxide, and reduce the onset risk of cardiovascular diseases by means of relaxing blood vessels, lowering blood pressure, inhibiting platelet adhesion and aggregation and maintaining vascular tension, and thus play an important role in preventing and treating the occurrence and development of cardiovascular diseases.
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Paragraph 0113; 0115
(2018/08/01)
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- Synthesis and Structural Characterization of the layered Selenogallate RbGaSe2
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The chalcogenogallate RbGaSe2 was synthesized by thermal decomposition of rubidium azide in the presence of gallium selenide and selenium. RbGaSe2 crystallizes in the monoclinic space group C2/c (no. 15) with the lattice parameters a = 10.954(1) ?, b = 10.949(1) ?, c = 16.064(1) ?, β = 99.841(4)°, V = 1898.2(2) ?3, and Z = 16 (single-crystal data, 20 °C) in the TlGaSe2 structure type. Its crystal structure features anionic layers 2∞[Ga4Se84–] with a van der Waals distance of 3.30(1) ?. Thermal analysis revealed a melting point of about 930 °C. Using UV/Vis diffuse reflectance spectroscopy, a wide bandgap of 3.16 eV was determined for the colorless semiconductor. The bonding situation in the compound was further compared with the isotypic cesium phases based on the results from Raman spectroscopy and DFT calculations. The slight shifts of the Raman bands suggest a slightly higher covalency of the rubidium compound.
- Friedrich, Daniel,Schlosser, Marc,Pfitzner, Arno
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p. 1589 - 1592
(2017/12/01)
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- Development of a Continuous Flow Sulfoxide Imidation Protocol Using Azide Sources under Superacidic Conditions
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The development of a continuous flow sulfoxide imidation protocol for a pharmaceutically relevant target molecule is described. Sulfoxide imidation is a key step in the preparation of certain ATR kinase inhibitors. Reactions with NaN3 or TMSN3 and concentrated sulfuric acid under literature conditions provided low conversions and poor selectivities. In contrast, reactions employing fuming sulfuric acid afforded the target sulfoximine with a selectivity of ~90% after a reaction time of only 10-15 min at 50 °C. The imidation reaction using TMSN3 as reagent was successfully performed in a flow reactor utilizing CH2Cl2/H2SO4 biphasic conditions. The mixture was subsequently quenched in-line with H2O. Phase separation, neutralization, and re-extraction with an organic solvent furnished the product in excellent purity and good yields, albeit with loss of chirality.
- Gutmann, Bernhard,Elsner, Petteri,O'Kearney-Mcmullan, Anne,Goundry, William,Roberge, Dominique M.,Kappe, C. Oliver
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p. 1062 - 1067
(2015/09/01)
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- Acid-base equilibrium dynamics in methanol and dimethyl sulfoxide probed by two-dimensional infrared spectroscopy
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Two-dimensional infrared (2DIR) spectroscopy, which has been proven to be an excellent experimental method for studying thermally-driven chemical processes, was successfully used to investigate the acid dissociation equilibrium of HN3 in methanol (CH3OH) and dimethyl sulfoxide (DMSO) for the first time. Our 2DIR experimental results indicate that the acid-base equilibrium occurs on picosecond timescales in CH3OH but that it occurs on much longer timescales in DMSO. Our results imply that the different timescales of the acid-base equilibrium originate from different proton transfer mechanisms between the acidic (HN3) and basic (N3-) species in CH3OH and DMSO. In CH3OH, the acid-base equilibrium is assisted by the surrounding CH3OH molecules which can directly donate H+ to N3- and accept H+ from HN3 and the proton migrates through the hydrogen-bonded chain of CH3OH. On the other hand, the acid-base equilibrium in DMSO occurs through the mutual diffusion of HN3 and N3- or direct proton transfer. Our 2DIR experimental results corroborate different proton transfer mechanisms in the acid-base equilibrium in protic (CH3OH) and aprotic (DMSO) solvents.
- Lee, Chiho,Son, Hyewon,Park, Sungnam
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p. 17557 - 17561
(2015/07/07)
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- Synthesis of unexpected bifunctionalized thiazoles by nucleophilic attack on allenyl isothiocyanate
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Treatment of allenyl isothiocyanate with a variety of nucleophiles leads to 5-methylthiazoles with a functional group at the 2-position. The same pattern of reactivity is also seen with N-aminophthalimide. In the presence of azide salt, hydrazoic acid, or N,N-disubstituted hydroxylamines, however, allenyl isothiocyanate is converted into bifunctionalized thiazoles. We explain the formation of these products by nucleophilic addition at the isothiocyanato moiety followed by ring closure and an N-N or N-O cleavage reaction to generate short-lived 2-imino-5-methylidenethiazole or 5-methylidenethiazol-2-one. Such intermediates are trapped by addition reactions to give the final heterocyclic compounds. In the case of N,N-disubstituted hydroxylamines, the primary addition products with allenyl isothiocyanate can be detected as unstable intermediates by IR and NMR spectroscopy.
- Jawabrah Al-Hourani, Baker,Richter, Frank,Vrobel, Kai,Banert, Klaus,Korb, Marcus,Rueffer, Tobias,Walfort, Bernhard,Lang, Heinrich
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p. 2899 - 2906
(2014/05/20)
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- Red emitting neutral fluorescent glycoconjugates for membrane optical imaging
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A family of neutral fluorescent probes was developed, mimicking the overall structure of natural glycolipids in order to optimize their membrane affinity. Nonreducing commercially available di- or trisaccharidic structures were connected to a push-pull ch
- Redon, Sébastien,Massin, Julien,Pouvreau, Sandrine,De Meulenaere, Evelien,Clays, Koen,Queneau, Yves,Andraud, Chantal,Girard-Egrot, Agnés,Bretonniére, Yann,Chambert, Stéphane
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p. 773 - 787
(2014/05/06)
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- Reactions of 1,3-dehydroadamantane with inorganic oxygen-free acids
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A convenient and efficient procedure has been developed for the synthesis of 1-azidoadamantane, 1-adamantyl isocyanate, and 1-adamantyl isothiocyanate by reaction of 1,3-dehydroadamantane with hydrazoic, isocyanic, and isothiocyanic acids, respectively, under mild conditions. The reaction of 1,3-dehydroadamantane with hydrogen cyanide under analogous conditions gives adamantane-1-carbonitrile in a poor yield which may be improved using hexane as solvent.
- Butov,Mokhov,Burmistrov,Saad,Pitushkin
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p. 1276 - 1278
(2015/01/08)
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- Synthesis and structural characterization of Cs2Ga 2Se5
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Cs2Ga2Se5 was obtained by the reaction of CsN3 with stoichiometric amounts of GaSe and Se at elevated temperature. It forms yellow crystals embedded in a pure orange microcrystalline powder. The crystal structure of Cs2Ga2Se5 was determined by single-crystal X-ray diffraction at 123 K. The compound crystallizes monoclinically in the space group C2/c (No. 15) with a = 15.3911(5) A, b = 7.3577(2) A, c = 12.9219(3) A, β = 126.395(3)°, V = 1177.89(7) A3, and Z = 4. The structure features one-dimensional chains 1∞[Ga 2Se3(Se2)2-], consisting of edge- and corner sharing GaSe4 tetrahedra. Raman spectroscopic measurements reveal vibrational bands of the Se22- units at 236 cm-1, and the bands of Ga-Se vibrations at 254 and 273 cm -1. UV/Vis diffuse reflectance spectroscopy shows the bandgap at about 1.95 eV. Copyright
- Friedrich, Daniel,Schlosser, Marc,Pfitzner, Arno
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p. 826 - 829
(2014/04/17)
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- Quantification of the 248 nm photolysis products of HCNO (fulminic Acid)
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IR diode laser spectroscopy was used to detect the products of HCNO (fulminic acid) photolysis at 248 nm. Five product channels are energetically possible at this photolysis wavelength: O + HCN, H + (NCO), CN + OH, CO + NH, and HNCO. In some experiments, isotopically labeled 18O2, 15N18O and C2D6 reagents were included into the photolysis mixture in order to suppress and/or isotopically label possible secondary reactions. HCN, OC18O, C18O, NCO, DCN, and NH molecules were detected upon laser photolysis of HCNO/reagents/buffer gas mixtures. Analysis of the yields of product molecules leads to the following photolysis quantum yields: 1a (O + HCN) = 0.39 ± 0.07, 1b (H + (NCO)) = 0.21 ± 0.04, 1c (CN + OH) = 0.16 ± 0.04, 1d (CN + NH(a1Δ)) = 0.19 0.03, and 1e (HNCO) = 0.05 ± 0.02, respectively. The uncertainties include both random errors (1σ) and consideration of major sources of systematic error. In conjunction with the photolysis experiment, the H + HCNO reaction was investigated. Experimental data demonstrate that this reaction is very slow and does not contribute significantly to the secondary chemistry.
- Feng, Wenhui,Hershberger, John F.
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p. 829 - 837
(2014/03/21)
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- Protective group-free synthesis of new chiral diamines via direct azidation of 1,1-diaryl-2-aminoethanols
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A direct azidation of tertiary alcohols using sodium azide-sulfuric acid is described; the present method provides an efficient and practical path for the synthesis of new chiral diamines from unmasked 1,1-diaryl-2-aminoethanols derived from natural amino
- Roy, Harendra Nath,Pitchaiah, Arigala,Kim, Miri,Hwang, In Taek,Lee, Kee-In
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p. 3526 - 3530
(2013/04/10)
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- Ruthenium-catalysed efficient asymmetric transfer hydrogenation of aromatic ketones using cinchona alkaloids as chiral ligands
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Cinchona alkaloid derivatives were applied in asymmetric transfer hydrogenation of aromatic ketones in a ruthenium catalytic system using i-PrOH as the hydrogen source. A series of aromatic ketones could be transfer-hydrogenated to the corresponding alcohols with good to excellent conversion and enantioselectivity. The best results were achieved using 9-amino(9-deoxy) epiquinidine as the ligand; the enantioselectivity with acetophenone and 2′-(trifluoromethyl)acetophenone could reach 90% ee.
- Jiang, Heyan
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p. 761 - 763
(2014/01/23)
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- Solid state structure of Bi(N3)3, Bi(N 3)3·solvates and the structural dynamics in the [Bi(N3)6]3- anion
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The highly explosive bismuth triazide, Bi(N3)3, was obtained in pure form by the reaction of BiF3 with Me 3SiN3 in acetonitrile under solvothermal conditions at temperatures between 90 and 100 °C. X-ray, 14N NMR, infrared, and Raman spectra are discussed along with the data for the acetonitrile, acetone, and dmso adducts. The influence of the solvent on the purity of the azide products is studied in detail for Bi(N3)3 and the [Bi(N3)6]3- ion. Moreover, temperature dependent structural dynamics in the [Bi(N3)6] 3- ion, which is caused by small changes in the local environment around the [Bi(N3)6]3- ion in the solid state, was studied by temperature variable single crystal X-ray and Raman studies. The azido-chlorido ligand back exchange was studied in detail by NMR techniques in [Bi(N3)6]3- and Bi(N3)3 when chlorinated solvents such as CH2Cl2 were utilized leading to the formation of CH2(N3)Cl and/or HN 3 along with partially chlorinated bismuth azides.
- Rosenstengel, Kati,Schulz, Axel,Villinger, Alexander
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supporting information
p. 6110 - 6126
(2013/07/05)
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- Facile, high-yield functionalization of germanium and tin by oxidative insertion of tetrelenes into the E-H bonds of inorganic acids (E = C, N, O, F): Arene elimination versus oxidative addition and formation of a germanium cation-water complex
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Reaction of the diarylgermylene Ge(ArMe6)2 [ArMe 6 = C6H3-2,6-(C6H 2-2,4,6-(CH3)3)2] with various inorganic acids (HCN, HN3, and HBF4) led to the facile oxidation of the germanium atom to yield the corresponding Ge(IV) products (ArMe6)2Ge(H)X (X = CN (1), N3 (2), F (3)). The cationic germanium-water complex [(ArMe6)2GeH(OH 2)][SO3CF3] (4) was prepared by treating Ge(ArMe6)2 with triflic acid in the presence of trace amounts of moisture. The reactions provide an efficient method of installing a variety of functional groups at a germanium atom and can be used in the preparation of germanium complexes that are analogous to lighter carbon species. The tin species Sn(Ar6)2 was also oxidized to the Sn(IV) analogue of 3. In all reactions, no evidence of arene elimination was observed, which was in contrast to the reaction of the stannylene (or bulkier germylenes) with hydrogen or ammonia, which yielded H(ArMe6), [(ArMe6)Sn(μ-H)]2, and [(ArMe6)Sn(μ- NH2)]2.
- Brown, Zachary D.,Erickson, Jeremy D.,Fettinger, James C.,Power, Philip P.
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p. 617 - 622
(2013/03/14)
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- Stereoselective total synthesis of (-)-batzellasides a, b, and c
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Total synthesis of (-)-L-batzellasides A, B, and C has been achieved in 13 steps from known lactone 2 in 12.6, 13.2, and 13.8 % overall yields, respectively. The key steps in this synthesis were the stereoselective introduction of an allyl group at the C1
- Okaki, Toru,Fujimura, Ryohei,Sekiguchi, Masataka,Zhou, Dejun,Sugimoto, Kenji,Minato, Daishiro,Matsuya, Yuji,Kato, Atsushi,Adachi, Isao,Tezuka, Yasuhiro,Saporito, Ralph A.,Toyooka, Naoki
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p. 2841 - 2848
(2013/07/11)
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- Stereoselective synthesis of chiral pyrrolidine derivatives of (+)-α-pinene containing a β-amino acid moiety
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We report the synthesis of several enantiopure pyrrolidine derivatives containing a β-amino acid moiety. These novel chiral compounds were prepared through stereospecific chlorosulfonyl isocyanate (CSI) addition to the readily available, natural terpene (+)-α-pinene. Coupling of N-Boc-protected β-amino acid derivatives with various bulky amines and amino acids using the mixed anhydride activation method, followed by N-deprotection, afforded the corresponding chiral amino amides in good yields. Despite the severe steric hindrance anticipated in α-pinene-based heterocycles, efficient coupling of the amino amides and an amino ester with the acyl chloride of N-Cbz-protected (S)-proline provided the corresponding pyrrolidinic pinene derivatives in good yields. Moreover, a convenient synthesis of N-Cbz- and N-Boc-monoprotected (S)-prolinamine is reported. Georg Thieme Verlag Stuttgart New York.
- Vega-Penaloza, Alberto,Sanchez-Antonio, Omar,Escudero-Casao, Margarita,Tasnadi, Gabor,Fueloep, Ferenc,Juaristi, Eusebio
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p. 2458 - 2468
(2013/09/23)
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- Synthesis of alkaline earth diazenides MAEN2 (M AE = Ca, Sr, Ba)by Controlled Thermal Decomposition of Azides under High Pressure
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The alkaline earth diazenides MAEN2 with M AE = Ca, Sr andBa were synthesized by a novel synthetic approach, namely, a controlleddecomposition of the corresponding azides in a multianvil press at highpressure/high-temperature conditions. The crystal structure of hithertounknown calcium diazenide (space group I4/mmm (no. 139), a = 3.5747(6)A, c = 5.9844(9)A, Z = 2, wRp = 0.078)was solved and refined on the basisof powder X-ray diffraction data as well as that of SrN 2 and BaN2.Accordingly, CaN2 is isotypic with SrN2 (space group I4/mmm (no. 139), a =3.8054(2)A, c = 6.8961(4)A, Z = 2, wRp = 0.057)and the correspondingalkaline earth acetylenides (MAEC2)crystallizing in a tetragonally distortedNaCl structure type. In accordance with literature data, BaN2 adopts a moredistorted structure in space group C2/c (no. 15)with a = 7.1608(4)A, b =4.3776(3)A, c = 7.2188(4)A, β = 104.9679(33)°, Z = 4 and wRp = 0.049).The N-N bond lengths of 1.202(4)A in CaN2 (SrN2 1.239(4)A, BaN21.23(2)A)correspond well with a double-bonded dinitrogen unit confirming a diazenide ion [N 2]2-. Temperature-dependent insitu powder X-ray diffractometry of the three alkaline earth diazenides resulted in formation of the corresponding subnitridesMAE2N (MAE = Ca, Sr, Ba)at higher temperatures. FTIR spectroscopy revealed a band at about 1380 cm-1 assigned to the N-Nstretching vibration of the diazenide unit. Electronic structure calculations support the metallic character of alkaline earthdiazenides.
- Schneider, Sebastian B.,Frankovsky, Rainer,Schnick, Wolfgang
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p. 2366 - 2373
(2012/04/18)
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- Experimental observation of the 16-electron molecules SPN, SNP, and cyclic PSN
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16-Electron triatomic ring: Novel thiazylidynephosphane (SNP) was produced by either flash vacuum pyrolysis (ca. 1000 °C) or laser photolysis (193 nm) of SP(N3)3. Its photointerconversion to cyclic thiazaphosphirine (cyc-PSN) and thiophosphoryl nitride (SPN) was found in Ar matrix at 16 K. Cyc-PSN is the first experimentally observed 16-electron cyclic triatomic molecule. Copyright
- Zeng, Xiaoqing,Beckers, Helmut,Willner, Helge,Francisco, Joseph S.
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p. 3334 - 3339
(2012/06/15)
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- Synthesis and biological evaluation (in Vitro and in Vivo) of cyclic arginine-glycine-aspartate (RGD) peptidomimetic-paclitaxel conjugates targeting integrin αvβ3
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A small library of integrin ligand-paclitaxel conjugates 10-13 was synthesized with the aim of using the tumor-homing cyclo[DKP-RGD] peptidomimetics for site-directed delivery of the cytotoxic drug. All the paclitaxel-RGD constructs 10-13 inhibited biotinylated vitronectin binding to the purified αVβ3 integrin receptor at low nanomolar concentration and showed in vitro cytotoxic activity against a panel of human tumor cell lines similar to that of paclitaxel. Among the cell lines, the cisplatin-resistant IGROV-1/Pt1 cells expressed high levels of integrin αVβ3, making them attractive to be tested in in vivo models. cyclo[DKP-f3-RGD]-PTX 11 displayed sufficient stability in physiological solution and in both human and murine plasma to be a good candidate for in vivo testing. In tumor-targeting experiments against the IGROV-1/Pt1 human ovarian carcinoma xenotransplanted in nude mice, compound 11 exhibited a superior activity compared with paclitaxel, despite the lower (about half) molar dosage used.
- Colombo, Raffaele,Mingozzi, Michele,Belvisi, Laura,Arosio, Daniela,Piarulli, Umberto,Carenini, Nives,Perego, Paola,Zaffaroni, Nadia,De Cesare, Michelandrea,Castiglioni, Vittoria,Scanziani, Eugenio,Gennari, Cesare
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supporting information
p. 10460 - 10474
(2013/02/22)
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- Biphenomycin B and derivatives: Total synthesis and translation inhibition
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A full account on the synthesis of the antibiotic natural product biphenomycin B and several derivatives is reported, which employs a Suzuki coupling reaction of a free carboxylic acid and macrolactam formation as key transformations. Liberal exchange of
- He, Yu-Peng,Tan, Hao,Arve, Lars,Baumann, Sascha,Waldmann, Herbert,Arndt, Hans-Dieter
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p. 1546 - 1556
(2013/01/11)
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- Inhibitors of protein kinases
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Compounds of general Formula (I): wherein R1, R2, R3, Ra, A, B and x are as defined herein are inhibitors of protein kinases in particular members of the cyclin-dependent kinase family and/or the glycogen synthase kinase 3 family and are useful in preventing and/or treating any type of pain, inflammatory disorders, cancer, immunological diseases, proliferative diseases, infectious diseases, cardiovascular diseases, metabolic disorders, renal diseases, neurologic and neuropsychiatric diseases and neurodegenerative diseases.
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Page/Page column 36
(2011/10/04)
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- INHIBITING NEUROTRANSMITTER REUPTAKE
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This document relates to compounds as well as methods and materials involved in modulating neurotransmitter reuptake. For example, compounds, methods for synthesizing compounds, and methods for inhibiting neurotransmitter reuptake are provided.
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Page/Page column 45-46; 48
(2009/09/04)
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- Preparation and characterization of the first organosulfonium azides
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The first triorganosulfonium azides [Me3S]N3 and Ph3S]N3 were prepared by reaction of the corresponding sulfonium bromides/iodides with silver azide and characterized by spectroscopic methods. The molecular stru
- Klaepotke, Thomas M.,Kramm, Burkhard,Scherr, Matthias
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p. 467 - 469
(2009/08/08)
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- ARYL HETEROCYCLIC CGRP RECEPTOR ANTAGONISTS
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Compounds of formula I: I (wherein variables A1, A2, B, m, n, J, X, R4, G1, G2, G3 and Y are as described herein) which are antagonists of CGRP receptors and which are useful in the treatme
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Page/Page column 53
(2008/12/08)
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- Synthesis and structures of triorganochalcogenium (Te, Se, S) dinitramides
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The syntheses of the triorganochalcogenium dinitramide salts [Ph 3Te][N(NO2)2] (1), [Me3Te][N(NO 2)2] (2), [Ph3Se]-[N(NO2) 2] (3), [Me3Se][N(NO2)2] (4), [Ph3S][N(NO2)2] (5), and [Me 3S][N(NO2)2] (6), their characterization by multinuclear NMR spectroscopy, vibrational spectra, and single-crystal structures are described. The syntheses of the compounds were achieved with the help of [Ag(py)2][N(NO2)2] and [Ag(NCCH 3)][N(NO2)2] as dinitramide transfer reagents. Whereas in the crystal structure of 1 different coordination modes to dinitramide moieties are present, the crystal structure of 3 shows only a single intermolecular contact to the dinitramide moiety. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Klapoetke, Thomas M.,Krumm, Burkhard,Scherr, Matthias
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p. 4413 - 4419
(2009/02/07)
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- Formation of chelated counteranions using lewis acidic diboranes: Relevance to isobutene polymerization
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The reactions of chelating diboranes with PhCMe2Cl and related initiators were studied by variabletemperature NMR spectroscopy. Although thermally stable ion-pairs featuring weakly coodinating anions (WCA) are formed, isobutene polymerization is complicated by the tendency of these WCA to act as hindered bases toward Bronsted acidic chain ends.
- Chai, Jianfang,Lewis, Stewart P.,Collins, Scott,Sciarone, Timo J.J.,Henderson, Lee D.,Chase, Preston A.,Irvine, Geoffrey J.,Piers, Warren E.,Elsegood, Mark R.J.,Clegg, William
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p. 5667 - 5679
(2008/10/09)
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- High-Pressure synthesis of BaSr2P6N12 and BaCa2P6N12 and comparison of the structures of BaP2N4, BaCa2P6N12, and BaSr2P6N12
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The novel nitridophosphates BaCa2P6N12 and BaSr2P6 N12 were obtained by means of high-pressure high-temperature synthesis utilizing the multianvil technique (1200°C, 5 GPa). The complex anion [PN2-] of the title compound is formally isoelectronic with silica. The crystal structure was solved from powder data and refined by the Rietveld method (BaCa 2P6N12: Pa3, Z = 4, a = 9,9578(2) A; BaSr2P6N12: Pa3, Z = 4, 10,0705(2) A). The crystal structures are derived from that of BaP2N4 which is isotypic with a high pressure phase of CaB2O4 and BaGa2S4. For each compound the 31P solid state NMR spectrum yielded a single resonance (BaCa2P6N 12: 7.4 ppm; BaSr2P6N12:3.9 ppm).
- Karau, Friedrich,Schnick, Wolfgang
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p. 231 - 237
(2008/10/09)
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- Hydrazine nitrosation of a metal-bound nitric oxide: Structural evidence for the formation of an ammine complex
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Hydrazine nitrosation of [Ru(NO)(pysiS4)] Br·THF (1) (pysiS42- = 2,6-bis(3-triphenylsilyl-2-sulfanylphenylthiomethyl)-pyridine2-) in methanol/DMF led to the formation of mononuclear ammine complex [Ru(NH 3)(pysiS4)] (2) and N2O, whereas the reaction performed in THF/CH2Cl2/toluene afforded thioether-bridged dinuclear ammine complex [(NH3)-Ru(μ-py siS4)Ru(pysiS4)] (3). Compound 2 dimerizes in solution at room temperature to form 3 and is regenerated upon treatment of 3 with NH3. A plausible mechanism for the hydrazine nitrosation of 1 has been proposed. The reaction of 1 with NH3 or N3- does not lead to a nucleophilic attack at the NO + ligand but to a deprotonation that yields neutral nitrosyl complex [Ru(NO){pysiS4(H+)}] (4), which is supported by density functional theory calculations.
- Prakash, Raju,Goetz, Andreas W.,Heinemann, Frank W.,Goerling, Andreas,Sellmann, Dieter
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p. 4661 - 4667
(2008/10/09)
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- Thermal hazard analysis of mixed system of hydrazine and nitric acid
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In order to obtain a better understanding of the thermal hazard of hydrazine and nitric acid mixtures which are used in plutonium and uranium recovery by extraction (PUREX) process during recycling of spent fuel in nuclear plant, DSC was carried out for the mixed system made by the small scale reaction calorimeter super-CRC in various conditions. It was found that the concentration of the nitric acid has a strong influence on the thermal behavior of the mixed system, and hydrazine nitrate which is formed in the reaction in the mixture was determined by DSC with FTIR analysis.
- Miyake,Kimura,Satoh,Shimizu,Inano,Ogawa
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p. 633 - 636
(2008/10/09)
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- New signal processing method for the faster observation of natural-abundance 15N NMR spectra and its application to N 5+
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The new harmonic inversion noise reduction method was applied to 15N natural-abundance NMR spectroscopy and N5SbF 6. This method is superior to conventional Fourier transform methods for processing FIDs and permits the det
- Kunikeev, Sharif D.,Taylor, Howard S.,Schroer, Thorsten,Haiges, Ralf,Jones, C. J. Bigler,Christe, Karl O.
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p. 437 - 442
(2008/10/09)
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- N-linked heterocyclic antagonists of P2Y1 receptor useful in the treatment of thrombotic conditions
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The present invention provides novel ureas containing N-aryl or N-heteroaryl substituted heterocycles of Formula (I): or a stereoisomer, tautomer, pharmaceutically acceptable salt or solvate form thereof, wherein the variables A, B, D and W are as defined herein. These compounds are selective inhibitors of the human P2Y1 receptor which can be used as medicaments.
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Page/Page column 79
(2010/11/25)
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- High-pressure synthesis and X-ray powder structure determination of the nitridophosphate BaP2N4
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The novel nitridophosphate BaP2N4 was obtained by means of high-pressure high-temperature synthesis utilizing the multianvil technique (8 GPa, 1400°C). The [PN2]- network is isoelectronic with silica. The structure was solved from synchrotron powder data by a combination of direct methods and difference FOURIER synthesis and refined using the RIETVELD method (BaP2N4, Pa3, Z = 12, a = 10.22992(2)A). BaP2N4 is isotypic with BaGa 2S4, BaAl2S4 and the high-pressure phase of CaB2O4. The 31P solid-state NMR yielded a single sharp resonance at 0.4 ppm.
- Karau, Friedrich W.,Schnick, Wolfgang
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p. 135 - 141
(2008/10/09)
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- Experimental and theoretical investigation of the reaction NH(X3Σ-) + H(2S) -> N(4S) + H2(X1Σg+)
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The rate coefficient of the reaction NH(X3Σ-) + H(2S) N(4S) + H2(X1Σg+) is determined in a quasistatic laser-flash photolysis, laser-induced fluorescence system at low pressures (2 mbar 1Δ) (obtained by photolyzing HN3) with Xe whereas the H atoms are generated in a H2/He microwave discharge. The NH(X) concentration profile is measured under pseudo-first-order condition, i.e., in the presence of a large excess of H atoms. The room temperature rate coefficient is determined to be k1a = (1.9 +/- 0.5)*1012 cm3 mol-1 s-1. It is found to be independent of the pressure in the range considered in the present experiment. A global potential energy surface for the 4A'' state is calculated with the internally contracted multireference configuration interaction method and the augmented correlation consistent polarized valence quadruple zeta atomic basis. The title reaction is investigated by classical trajectory calculations on this surface. The theoretical room temperature rate coefficient is k1a = 0.92*1012 cm3 mol-1 s-1. Using the thermodynamical data for the atoms and molecules involved, the rate coefficient for the reverse reaction, k-1a, is also calculated. At high temperatures it agrees well with the measured k-1a.
- Adam, L.,Hack, W.,Zhu, H.,Qu, Z.-W.,Schinke, R.
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- Time resolved resonance Raman observation of the extreme protonation forms of a radical zwitterion in water
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The reactions of the aqueous proton with the zwitterionic p-aminophenoxyl radical in strongly basic to extremely acidic aqueous solutions have been investigated using time-resolved resonance Raman spectroscopy. The dynamic stability of the different protonation forms of the radical, observed on the microsecond time scale in this work, has been achieved by controlling the proton exchange rate in water. In strongly acidic solutions we observe a rare ring-H+ bonded dication species, a key intermediate in the amine hydrolysis. The neutral p-aminophenoxyl radical undergoes NH2- deprotonation in strongly basic aqueous solutions, which has no analogues in closed-shell amines.
- Tripathi
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- The four isotopomer reactions of NH(a) and ND(a) with NH3(X) and ND3(X)
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The reactions NH(a) + NH3 (X) → products (1) ND(a) + NH3 (X) → products (2) NH(a) + ND3 (X) → products (3) ND(a) + ND3 (X) → products (4) were studied in a quasi-static reaction cell at room temperature and pressures of 10 and 20 mbar with He as the main carrier gas. The electronically excited reactants NH(a) and ND(a) were generated by laser-flash photolysis of HN3 and DN3, respectively, at λ = 308 nm and detected by laser-induced fluorescence (LIF). Also the ground state species NH(X) and ND(X) as products were detected by LIF. From the measured concentration-time profiles of NH(a) and ND(a) under pseudo-first order conditions, the following rate constants were obtained: k1, = (9.1 ± 0.9) × 1013 cm3 mol-1 s-1 k2 = (9.6 ± 1.0) × 1013 cm3 mol-1 s-1 k3 = (8.0 ± 1.0) × 1013 cm3 mol-1 s-1 k4 = (7.2 ± 0.8) × 1013 cm3 mol-1 s-1. The major products are the corresponding NHi-D2-i(X) radicals (i = 0, 1, 2), whereas quenching processes such as NH(a) + ND3 → NH(X) + ND3 are of minor importance (1%). The isotope exchange NH(a) + ND3 → ND(X) + NHD2 is negligible, and the corresponding channel on the singlet surface NH(a) + ND3(X) → ND(a) + NHD2 (X) contributes with 1% to the overall NH(a) depletion in that reaction. The experimental findings are discussed in terms of a chemical activation mechanism by means of statistical rate theory.
- Adam,Hack,Olzmann
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p. 439 - 455
(2007/10/03)
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