- Femtosecond TRIR studies of CINO photochemistry in solution: Evidence for photoisomerization and geminate recombination
-
The photochemistry of nitrosyl chloride (ClNO) in the solution phase is investigated using Fourier transform infrared (FTIR) and ultrafast time-resolved infrared (TRIR) spectroscopies. The NO-stretch fundamental transition for ClNO dissolved in cyclohexan
- Bixby, Teresa J.,Patterson, Joshua D.,Reid, Philip J.
-
-
Read Online
- New systems for classical nitrosohalogenation of alkenes 2. Generation of nitrosyl chloride in AgNO2-SOCl2 and AgNO 3-SOCl2 systems
-
Study of the reactions of compounds of the norbornene series demonstrated that the AgNO2-SOCl2 and AgNO3-SOCl2 systems serve as nitrosochlorinating agents under the conditions of electrophilic addition. X-ray di
- Bondarenko,Gavrilova,Tikhanushkina,Zyk
-
-
Read Online
- Synthesis and structures of CuI,II complexes with a 2,2′-bipyridine derivative bearing a (+)-3-carene moiety
-
The complex salt {[CuL2][Cu4I6]?MeCN}n (1) and the compound [Cu4L3I4]?3 MeCN (2) (L is a chiral ligand bearing a natural monoterpene (+)-3-carene moiety) were synthesized. The crystal structures of compounds 1 and 2 were determined by X-ray diffraction. The structure of compound 1 consists of complex cations [CuL2]2+ (N3O2 polyhedron is a trigonal bipyramid) and CuI coordination polymers (CuI4 polyhedron is a tetrahedron) as anions. The experimental magnetic moment μeff at 300 K is 1.90 μB, which is consistent with the X-ray diffraction data and the assumption that compound 1 is mixed-valence. The structure of compound 2 comprises a tetranuclear CuI complex, in which three Cu atoms are coordinated by two N atoms of the ligand L and two I atoms, and the fourth Cu atom is coordinated by four I atoms (coordination polyhedra are distorted tetrahedra). Compounds L and 2 were found to influence the viability of human laryngeal carcinoma cells (Hep2). The IC50 value for complex 2 (13.0±1.7 μM) is substantially smaller than IC50 for compound L (30.5±0.5 μM).
- Kokina,Glinskaya,Piryazev,Baranov, A. Yu.,Agafontsev,Eremina, Yu. A.,Vorontsova,Bogomyakov,Naumov, D. Yu.,Tkachev,Larionov
-
-
Read Online
- Multistate photochemical reaction dynamics of ClNO in solution: An absolute resonance Raman intensity analysis study
-
The excited-state reaction dynamics of nitrosyl chloride (ClNO) are studied using absolute resonance Raman intensity analysis. The absolute resonance Raman cross sections for ClNO dissolved in cyclohexane and acetonitrile are measured at several excitation wavelengths spanning the absorption band commonly referred to as the A band (??max a?? 200 nm). The resonance Raman and absorption cross sections are modeled using the time-dependent formalism. Resonance Raman depolarization ratios are also measured and are found to be consistent with at least two electronic transitions participating in the scattering process. Therefore, the standard time-dependent formalism approach was modified by incorporating two excited states into the analysis, with state contributions deconvolved through modeling of the depolarization ratios in addition to the absolute resonance Raman and absorption cross sections. The spectroscopic observables are well reproduced using this two-state model. The analysis presented here demonstrates that the photoexcitation of solution-phase ClNO results in a substantial evolution of the N-Cl stretch coordinate consistent with the dissociation of the N-Cl bond. Significant structural evolution is also observed along the bend, with minimal excited-state structural evolution observed along the N=O stretch. The structural evolution along the dissociative N-Cl stretch coordinate is found to be solvent-dependent, and the origin of this dependence is related to changes in the ground-state equilibrium geometry as a function of solvent environment. Finally, the homogeneous line width undergoes a significant increase in acetonitrile relative to cyclohexane, and this increase is proposed to reflect the modification of the excited-state interactions and nonadiabatic relaxation dynamics.
- Nyholm, Bethany P.,Reid, Philip J.
-
-
Read Online
- Differing reactivities of (trimpsi)M(CO)2(NO) complexes [M = V, Nb, Ta; trimpsi = tBuSi(CH2PMe2)3] with halogens and halogen sources
-
Treatment of (trimpsi)V(CO)2(NO) (trimpsi: rBuSi(CH2PMe2)3) with 1 equiv of PhlCl2 or C2Cl6 or 2 equiv of AgCl affords (trimpsi)V(NO)Cl2 (1) in moderate yields. Likewise, (trimpsi)V(NO)Br2 (2) and (trimpsi)V(NO)l2 (3) are formed by the reactions of (trimpsi)V(CO)2(NO) with Br2 and l2, respectively. The complexes (trimpsi)M(NO)l2(PMe3) (M = Nb, 4; Ta, 5) can be isolated in moderate to low yields when the (trimpsi)M(CO)2(NO) compounds are sequentially treated with 1 equiv of 12 and excess PMe3. The reaction of (trimpsi)V(CO)2(NO) with 2 equiv of CINO forms 1 in low yield, but the reactions of (trimpsi)M(CO)2(NO) (M = Nb, Ta) with 1 equiv of CINO generate (trimpsi)M(NO)2Cl (M = Nb, 6; Ta, 7). Complexes 6 and 7 are thermally unstable and decompose quickly at room temperature; consequently, they have been characterized solely by IR and 31 P{1H} NMR spectroscopies. All other new complexes have been fully characterized by standard methods, and the solid-state molecular structures of 1·3CH2Cl2, 4·(3/4)CH2Cl2, and 5·THF have been established by single-crystal X-ray diffraction analyses. A convenient method of generating Cl15NO has also been developed during the course of these investigations.
- Hayton, Trevor W.,Legzdins, Peter,Patrick, Brian O.
-
-
Read Online
- Atmospheric chemistry of C2F5CHO: reaction with Cl atoms and OH radicals, IR spectrum of C2F5C(O)O2NO2
-
Smog chamber/FTIR techniques were used to measure k(Cl + C2F5CHO) = (1.96+/-0.28) x 10-12 and k(OH + C2F5CHO) = (5.26+/-0.80) x 10-13 cm3 molecule-1 s-1 in 700 Torr of N2 or air at 296+/-2 K. The Cl i
- Andersen, M. P. Sulbaek,Hurley, M. D.,Wallington, T. J.,Ball, J. C.,Martin, J. W.,Ellis, D. A.,Mabury, S. A.,Nielsen, O. J.
-
-
Read Online
- Kinetic study of an autocatalytic reaction: Nitrosation of formamidine disulfide
-
The reaction kinetics for the acid nitrosation of formamidine disulfide (FDS) show an autocatalytic behavior that arises from the fact that the thiocyanate ion formed as a product acts as a powerful catalyst for the nitrosation reaction. In the presence of added nucleophiles the suppression of the autocatalytic route results from competition for the nitrous acid between the added halides and the thiocyanate anion, which is formed as a reaction product. Analysis of the kinetic data enabled extraction of the bimolecular rate constants, kNO+ = (3.2 ± 1.8) × 1010 M -1 s-1; kNOSCN = (2.1 ± 0.2) × 105 M-1 s-1; kNOBr = (9.4 ± 0.2) × 106 M-1 s1 and kNOCl = (4.0 ± 0.2) × 107 M-1 s-1, for the pathways catalyzed by SCN-, Br- and Cl-, respectively. Kinetic results are consistent with the attack on the nitrosating agent as the rate limiting step, i.e., the nitrosation of FDS behaves in a similar manner to the nitrosation of an amine. Rather different behavior is found for other substrates with an imino moiety adjacent to an amino nitrogen, such as the guanidines, which react by a mechanism in which the rate limiting step is the reorganization of the nitrosated substrate. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2008.
- Francisco, Vitor,Garcia-Rio, Luis,Antonio Moreira, Jose,Stedman, Geoffrey
-
-
Read Online
- New details concerning the reactions of nitric oxide with vanadium tetrachloride
-
The slow addition of NO to a CCl4 solution of VCl4 reproducibly forms the known polymer [V(NO)3Cl2 ]n as a dark brown powder. Treatment of a CH2Cl 2 suspension of [V(NO)3Cl2]n with excess THF generates mer-(THF)3V(NO)Cl2 (1) which can be isolated as an orange crystalline material in 55% yield. The reaction of 1 with excess MeCN or 1 equiv of trimpsi (trimpsi = tBuSi(CH 2PMe2)3) provides yellow-orange (MeCN) 3V(NO)Cl2·MeCN (2·MeCN) and yellow (trimpsi)V(NO)Cl2 (3), respectively. A black, crystalline complex formulated as [NO][VCl5] (4) is formed by the slow addition of NO to neat VCl4 or by the reaction of excess CINO with neat VCl 4. Complex 4 is extremely air- and moisture-sensitive, and IR spectroscopy suggests that in solutions and in the gas phase it dissociates back into VCl4 and CINO. Reaction of 4 with excess [NEt 3(CH2Ph)]CI generates [NEt3(CH 2Ph)]2[VCl6]·2CH2Cl 2 (5·2CH2Cl2), which can be isolated as deep-red crystals in 51% yield. All new complexes have been characterized by conventional spectroscopic methods, and the solid-state molecular structures of 1, 2·MeCN, and 5·2CH2Cl2 have been established by single-crystal X-ray diffraction analyses.
- Hayton, Trevor W.,Patrick, Brian O.,Legzdins, Peter
-
-
Read Online
- Diffuse reflectance infrared studies of the reaction of synthetic sea salt mixtures with NO2: A key role for hydrates in the kinetics and mechanism
-
The heterogeneous reactions of oxides of nitrogen with NaCl as a model for sea salt particles have been the focus of many studies, due to their potential to act as precursors to atomic halogens in the troposphere. While a great deal has been learned about the kinetics and mechanisms of NaCl reactions, it is not clear how well this extrapolates to the complex mixture of inorganics found in sea salt. We report here diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) studies in which nitrate formation on the salt surface is followed with time during the reaction of gaseous NO2 with synthetic sea salt at 298 K in the presence of either He or air as the carrier gas. The infrared bands due to surface nitrate formed during the reaction of NO2 are shown to be similar to those from the reaction of MgCl2·OH2O, a major hydrate in the mixture which was used as a surrogate for all of the crystalline hydrates. Significant amounts of surface-adsorbed water are generated in the reaction of synthetic sea salt with NO2 in air, which appears at least in part to be due to liberation of bound water of hydration in the crystalline hydrates. The reaction order with respect to NO2 is (1.8 ± 0.2) (2σ) when the reaction of the synthetic sea salt is carried out in He but only (1.2 ± 0.2) (2σ) when air is used as the carrier gas. For comparison, the reaction order for the NO2-NaCl reaction was reexamined and found to be (1.8 ± 0.3) (2σ) in He and (1.6 ± 0.3) (2σ) in air, in agreement with previous work19 using this technique. It is assumed for slopes ≥ 1.6 that N2O4 is the reacting species for the purpose of expressing the kinetics in the usual form of reaction probabilities. For the N2O4-NaCl reactions in He and air, and for the N2O4-synthetic sea salt reaction in He, the reaction probabilities are similar (~10-4). The reaction of synthetic sea salt with NO2 in the presence of air is treated in terms of a first-order reaction with NO2 being the reactive species, which gives a reaction probability for the NO2-synthetic sea salt reaction of ~10-8. The atmospheric implications are discussed.
- Langer, Sarka,Pemberton, R. Sean,Finlayson-Pitts, Barbara J.
-
-
Read Online
- Temperature Dependence of the OH + ClNO Reaction: Evidence for two Competing Reaction Channels
-
The temperature dependence of the reaction of OH with nitrosyl chloride, ClNO, has been studied from 263 to 373 K in a fast-flow discharge system.The decay of OH in the presence of excess ClNO was followed by resonance fluorescence at 309.5 nm.The total pressure was 1.05+/-0.05 torr in He as the carrier gas.The rate constant increases both above and below room temperature suggesting the existence of two competing reaction paths, a direct abstraction reaction, HO + ClNO -> HOCl + NO (1a) and one involving formation of an intermediate complex, HO + ClNO * -> HONO + Cl (1b).This supports the interpretation of the room temperature product data of Poulet and co-workers.
- Finlayson-Pitts, B. J.,Ezell, M. J.,Grant, C. E.
-
-
Read Online
- UV resonance Raman studies of C1NO in solution
-
The first resonance Raman spectra of nitrosyl chloride (ClNO) in solution obtained with excitation resonant with the A-band are reported. For ClNO dissolved in cyclohexane, intensity is observed for transitions corresponding to all three normal coordinates: the bend, NCl stretch and NO stretch. This observation demonstrates that excited-state structural evolution occurs along these coordinates following photoexcitation resonant with the A-band. Resonance Raman depolarization ratios measured at excitation wavelengths spanning the A-band are reported. The depolarization ratios are found to be less that 1/3 consistent with at least two electronic transitions contributing to the A-band absorption intensity.
- Barham, Bethany P.,Reid, Philip J.
-
-
Read Online
- Surface-catalyzed chlorine and nitrogen activation: Mechanisms for the heterogeneous formation of ClNO, NO, NO2, HONO, and N2O from HNO3 and HCl on aluminum oxide particle surfaces
-
It is well-known that chlorine active species (e.g., Cl2, ClONO2, ClONO) can form from heterogeneous reactions between nitrogen oxides and hydrogen chloride on aerosol particle surfaces in the stratosphere. However, less is known about these reactions in the troposphere. In this study, a potential new heterogeneous pathway involving reaction of gaseous HCl and HNO3 on aluminum oxide particle surfaces, a proxy for mineral dust in the troposphere, is proposed. We combine transmission Fourier transform infrared spectroscopy with X-ray photoelectron spectroscopy to investigate changes in the composition of both gas-phase and surface-bound species during the reaction under different environmental conditions of relative humidity and simulated solar radiation. Exposure of surface nitrate-coated aluminum oxide particles, from prereaction with nitric acid, to gaseous HCl yields several gas-phase products, including ClNO, NO2, and HNO3, under dry (RH 20%), NO and N2O are the only gas products observed. The experimental data suggest that, in the presence of adsorbed water, ClNO is hydrolyzed on the particle surface to yield NO and NO2, potentially via a HONO intermediate. NO2 undergoes further hydrolysis via a surface-mediated process, resulting in N2O as an additional nitrogen-containing product. In the presence of broad-band irradiation (λ > 300 nm) gas-phase products can undergo photochemistry, e.g., ClNO photodissociates to NO and chlorine atoms. The gas-phase product distribution also depends on particle mineralogy (Al2O3 vs CaCO3) and the presence of other coadsorbed gases (e.g., NH3). These newly identified reaction pathways discussed here involve continuous production of active ozone-depleting chlorine and nitrogen species from stable sinks such as gas-phase HCl and HNO3 as a result of heterogeneous surface reactions. Given that aluminosilicates represent a major fraction of mineral dust aerosol, aluminum oxide can be used as a model system to begin to understand various aspects of possible reactions on mineral dust aerosol surfaces.
- Rubasinghege, Gayan,Grassian, Vicki H.
-
-
Read Online
- Resonance Raman spectroscopy in the dissociative A band of nitrosyl chloride
-
Resonance Raman spectra were obtained for CINO at three wavelengths in the ultraviolet A band. Twelve previously unobserved vibrational levels in the ground state were observed. These new levels, together with previously known vibrational levels, allowed the construction of a large amplitude vibrational model valid in and beyond the Franck-Condon region. The ground state surface showed a large degree of separability in Jacobi coordinates even in the triatomic molecular region.
- Mackey,Johnson,Kittrell,Le,Kinsey
-
-
Read Online
- Anhydrous Dinitrogen Trioxide Solutions for Br?nsted Acid Free Nitrous Acid Chemistry
-
Dinitrogen trioxide, N2O3, is readily prepared and stabilized in high concentrations in dry organic solvents at normal working temperatures. These conditions allow for facile acid and water free nitrosation and nitration reactions fo
- Rosadiuk, Kristopher A.,Bohle, D. Scott
-
p. 5461 - 5465
(2017/12/26)
-
- Developing nitrosocarborane chemistry
-
The new nitrosocarboranes [1-NO-2-R-1,2-closo-C2B10H10] [R = CH2Cl (1), CH3OCH2 (2) p-MeC6H4 (3), SiMe3 (4) and SiMe2tBu (5)] and [1-NO-7-Ph-1,7-closo-C2B10H10] (6) were synthesised by reaction of the appropriate lithiocarborane in diethyl ether with NOCl in petroleum ether followed by quenching the reaction with aqueous NaHCO3. These bright-blue compounds were characterised spectroscopically and, in several cases, crystallographically including structural determinations of 2 and 6 using crystals grown in situ on the diffractometer from liquid samples. In all cases the nitroso group bonds to the carborane as a 1e substituent (bent C-N-O sequence) and has little or no influence on 11B>, the weighted average 11B chemical shift, relative to that in the parent (monosubstituted) carborane. Mono- and dinitroso derivatives of 1,1′-bis(m-carborane), compounds 7 and 8 respectively, were similarly synthesised but attempts to prepare the mononitroso 1,1′-bis(o-carborane) by the same protocol led only to the hydroxylamine species [1-(1′-1′,2′-closo-C2B10H11)-2-N(H)OH-1,2-closo-C2B10H10] (9); the desired compound [1-(1′-1′,2′-closo-C2B10H11)-2-NO-1,2-closo-C2B10H10] (10) was only realised by switching to a non-aqueous work-up. The involvement of water in effecting the net reduction of the NO function in 10 to N(H)OH in 9 was confirmed by a series of experiments involving [1-N(H)OH-2-Ph-1,2-closo-C2B10H10] (11), [1-(1′-2′-D-1′,2′-closo-C2B10H10)-2-D-1,2-closo-C2B10H10] (12) and [1-(1′-2′-D-1′,2′-closo-C2B10H10)-2-N(H)OH-1,2-closo-C2B10H10] (13). It is suggested that during aqueous work-up a water molecule, H-bonded to the acidic C2′H of 10, is "delivered" to the adjacent C2NO unit. The ability of the NO group in nitrosocarboranes to undergo Diels-Alder cycloaddition reactions with cyclic 1,3-dienes was established via the syntheses of [1-(NOC10H14)-1,2-closo-C2B10H11] (14) and [1-(NOC6H8)-2-Ph-1,2-closo-C2B10H10] (15). This strategy was then utilised to prepare derivatives of the elusive dinitroso compounds of [1,2-closo-C2B10H12] and 1,1′-bis(o-carborane) leading to the sterically-crowded products [1,2-(NOC6H8)2-1,2-closo-C2B10H10] (16, prepared as meso and racemic diastereoisomers), [1-{1′-2′-(NOC6H8)-1′,2′-closo-C2B10H10}-2-(NOC6H8)-1,2-closo-C2B10H10] (17) and [1-(1′-1′,2′-closo-C2B10H11)-2-(NOC6H8)-1,2-closo-C2B10H10] (18).
- Powley, Samuel L.,Schaefer, Louise,Man, Wing. Y.,Ellis, David,Rosair, Georgina M.,Welch, Alan J.
-
p. 3635 - 3647
(2016/03/05)
-
- Reaction of trans-[RuNO(NH3)4(OH)]Cl2 with nitric acid and synthesis of ammine(nitrato)nitrosoruthenium complexes
-
The reaction of trans-[RuNO(NH3)4(OH)]Cl2 with nitric acid has been studied. Reaction prod- ucts have been identified by IR spectroscopy, NMR, mass spectrometry, powder and single-crystal X-ray dif- fraction, and chemical
- Kabin,Emel'yanov,Vorob'yev,Alferova,Tkachev,Baidina
-
p. 1146 - 1153
(2012/10/08)
-
- Nitrosonium hexachlorostannate: Synthesis, crystal structure, and nitrosating activity in the reactions with arylcyclopropanes
-
Nitrosonium hexachlorostannate (NO)2[SnCl6] was synthesized by the reaction of NOCl and SnCl4 in CH 2Cl2. According to the single-crystal X-ray diffraction analysis data, the structure of (NO)2[SnCl6] consists of cations NO+ and octahedral anions [SnCl6]2- arranged as ions in antifluorite. Isoxazolines were synthesized by the reactions of (NO)2[SnCl6] with arylcyclopropanes containing donor substituents in the aromatic ring.
- Morozov,Bondarenko,Karpova,Pryadchenko,Korenev,Troyanov,Zyk
-
p. 1921 - 1924
(2011/06/27)
-
- Atmospheric chemistry of C2F5CHO: Reaction with Cl atoms and OH radicals, IR spectrum of C2F5C(O)O 2NO2
-
Smog chamber/FTIR techniques were used to measure k(Cl+C2F 5CHO)=(1.96±0.28)×10-12 and k(OH+C 2F5CHO)=(5.26±0.80)×10-13 cm 3 molecule-1 s-1 in 700 Torr of N
- Sulbaek Andersen,Hurley,Wallington,Ball,Martin,Ellis,Mabury,Nielsen
-
-
- Matrix infrared spectroscopic studies of the photo-dissociation at 266 nm of C1NO2 and of C1ONO
-
Detailed infrared spectroscopic studies of the photo-dissociation at 266 nm of C1NO2 trapped in argon matrices with subsequent experiments conducted with a xenon lamp at λ > 360 nm are reported. Formation of cis and trans C1ONO in equilibrium with C1NO2 is observed after irradiation at 266 nm. λ > 360 nm the transformation of trans C1ONO into cis C1ONO occurs. On prolonged photolysis at 266 nm, C1ONO dissociates into C1ON and O(1D) atom and into C10 + NO as evidenced in reactive matrices (solid oxygen and nitrogen).
- Coanga,Schriver-Mazzuoli,Schriver,Dahoo
-
p. 309 - 320
(2008/10/08)
-
- Photofragmentation of nitryl chloride in the ultraviolet regime and vacuum ultraviolet regime
-
Photofragmentation of nitryl chloride (ClNO2) is reported in the ultraviolet (UV) (λ = 240 nm and λ = 308 nm) and in the vacuum ultraviolet (VUV) regime (55 nm ≤ λ ≤ 110 nm, corresponding to the photon energy range 11.3 eV ≤ E ≤ 22.5 eV), where pulsed radiation is used to excite the neutral molecule in the gas phase. The neutral photolysis products that are formed upon UV photolysis are subsequently probed by photoionization mass spectrometry by using time-correlated tunable laser-produced plasma VUV radiation. UV-pump/VUV-probe experiments allow us to identify two primary photolysis channels at λ = 308 nm: (i) Cl + NO2 and (ii) O + ClNO. Primary quantum yields for atomic product formation are deduced from photoionization experiments for both channels: γ308 nm(Cl) = 0.93 ± 0.10, and γ308 nm(O) = 0.07 + 0.01. The yield of Cl formation (N(Cl)) is significantly reduced relative to that of O formation (N(O)) at λ = 240 nm, corresponding to a N(Cl)/N(O) ratio of 1.44 ± 0.15. The atomic oxygen is found to be formed in its 3P ground state at both photolysis wavelengths. The present results are compared to earlier work, and atmospheric implications of the present results are briefly discussed. The tunable VUV light source also allows us to perform photoionization mass spectrometry experiments on nitryl chloride without primary photolysis. These experiments yield the first ionization energy of ClNO2 as well as fragmentation thresholds of ClNO2+.
- Plenge,Flesch,Schuermann,Ruehl
-
p. 4844 - 4850
(2007/10/03)
-
- Method for hardening powder coatings
-
Process for curing powder lacquers by coating substrates with the powder lacquers and irradiating by radiation in the near infrared range (NIR radiation), which is characterized in that the curing times and/or the surface temperatures, obtainable by means of the radiation during certain curing times, of the substrates coated with the powder lacquers are controlled by setting the barium sulfate and/or aluminium oxide content of the powder lacquers to 1 to 50 wt. % and/or setting the carbon black content of the powder lacquers to 0.1 to 5 wt. %, the percentages by weight relating to the entire powder lacquer composition in each case.
- -
-
-
- A unique method for laboratory quantification of gaseous nitrous acid (HONO) using the reaction HONO + HCL → ClNO + H2O
-
A novel method for quantifying gaseous HONO in laboratory systems has been developed. The technique uses the reaction of gas phase HONO with an excess of HCl gas to yield nitrosyl chloride (ClNO), which was quantified using FTIR. The gas-phase reaction of HONO with HCl formed ClNO with a stoichiometry of 0.9 ± 0.2 (1σ), i.e., within experimental error of unity. The concentration-time profiles for HONO and ClNO were fitted with a kinetics model, which showed that the reaction HONO + HCl → ClNO + ClNO was slow (k1 ≤ (1.9 ± 1.3) x 10-19/mole-sec (2σ) at 297 K. However, the reaction was a useful approach for quantifying HONO in laboratory systems because calibration for ClNO can be readily made. The method is better than UV/visible spectroscopy in that it does away with the more complex data associated with DOAS and other species (e.g., HNO3), which cannot be measured by DOAS, can be determined. Compared to the denuder and NOx detector approaches, the method is also more direct and specific.
- Wingen, Lisa M.,Barney, William S.,Lakin, Matthew J.,Brauers, Theo,Finlayson-Pitts, Barbara J.
-
p. 329 - 335
(2007/10/03)
-
- Photoluminescent properties of cadmium selenide in contact with solutions and films of metalloporphyrins: Nitric oxide sensing and evidence for the aversion of an analyte to a buried semiconductor-film interface
-
The band-edge photoluminescence (PL) intensity of etched n-CdSe single crystals is quenched reversibly by adsorption of the trivalent metalloporphyrins, MTPPCl (TPP = tetraphenylporphyrin; M = Mn, Fe, Co) in nitrogen-saturated methylene chloride solution. The PL responses are concentration dependent and can be fit to the Langmuir adsorption isotherm model to yield binding constants of ~103-104 M-1. The MTPPCl compounds react irreversibly with NO in solution to form nitrosyl adducts, and these compounds reversibly enhance the CdSe PL intensity when adsorbed onto the semiconductor surface, also with binding constants of ~103-104 M-1. Films of MTPPCl were prepared on CdSe substrates by solvent evaporation. These coatings serve as transducers for NO detection: while the bare CdSe surface shows no response to NO gas relative to N2, the coated surfaces reversibly enhance the PL intensity (CoTPPCl) or quench it (MnTPPCl and FeTPPCl), with binding constants on the order of ~1 atm-1. In contrast to the PL results, which are particularly sensitive to the semiconductor-film interface, electronic and IR spectral changes of the bulk film induced by NO binding were irreversible. The UV-vis and IR spectra could be spectroscopically mimicked by preformed nitrosyl adduct films that were prepared by solvent evaporation of MTPPCl (M = Co, Fe) and MTPP (M = Co) solutions that had been exposed to NO. These films, however, lack transduction capability, as the PL intensity is the same in NO and N2 ambients. For the films prepared from FeTPPCl and CoTPPCl, the saturation of IR and UV-vis spectral changes occurs at NO pressures at least 10-fold lower than observed for PL changes. These results indicate that NO has a strong aversion to binding at the semiconductor-film interface as opposed to the bulk film environment. Steric and electronic contributions to these observed effects are discussed.
- Ivanisevic, Albena,Reynolds, Mark F.,Burstyn, Judith N.,Ellis, Arthur B.
-
p. 3731 - 3738
(2007/10/03)
-
- State-resolved photofragmentation of [ClNO]n van der Waals clusters in a supersonic jet
-
The effects of the ultraviolet laser irradiation of [ClNO]2, weakly bound clusters, formed in a supersonic jet, are analyzed by considering three processes: the photofragmentation of bare ClNO, the Cl+ClNO reaction, and NO relaxation within the cluster. The photofragmentation of jet-cooled ClNO at 355 nm produces NO (υ″ = 1) with a kinetic energy of 2240 cm-1, a spin-orbit preference of F1/F2 = 1.2, and Λ-doublet state preferences of Π(A″)/Π±(A″) = 2.0 and 4.0 for the F1 and F2 manifolds, respectively. The NO distribution of rotational states was parametrized using a Gaussian function centered at N = 34, with a fwhm of 17. On the other hand, the Cl+ClNO reaction, studied at a collision energy of 2780 cm-1, gives NO(υ″ = 1) described by a Boltzmann rotational distribution with Trot = 950±100 K. The relative population of the NO spin-orbit states is F1/F2 = 2.5, with a Λ-doublet state preference of Π(A″)/Π(A′) = 1.2 and Etrans(NO) of 578 cm-1. It is found that 57% of available energy is disposed as Eint(Cl2). As a result of the irradiation of the [ClNO]n, clusters at 355 nm are observed: Boltzmann ensembles of NO(υ″ = 1) and NO(υ″ = 0) molecules described by Trot of 310±30 and 170±25 K, respectively, with no spin-orbit or Λ-doublet state preferences, overlapped with a Gaussian distribution already assigned to the NO photofragment. The relative contribution of the NO(υ″ = 1) photofragment to the spectra is drastically reduced upon increasing the backing pressure, as it undergoes translational and rotational relaxation within the clusters. Our high-resolution studies provide evidence that suggests that the reaction takes place within the [ClNO]n clusters.
- Conde, Carlos,Maul, Christof,Quinones, Edwin
-
p. 1929 - 1938
(2007/10/03)
-
- Atmospheric Chemistry of FNO and FNO2: Reactions of FNO with O3, O(3P), HO2, and HCl and the Reaction of FNO2 with O3
-
Upper limits for the rate constants of the following gas phase reactions have been determined at 296 K: k(FNO+O3) -18, k(FNO+O(3P)) -13, k(FNO+HO2) -12, k(FNO+HCl) -18, and k(FNO2+O3) 8
- Wallington, Timothy J.,Schneider, William F.,Szente, Joseph J.,Maricq, M. Matti,Nielsen, Ole John,Sehested, Jens
-
p. 984 - 989
(2007/10/02)
-
- Structure, Harmonic Force Field and Hyperfine Coupling Constants of Nitrosyl Chloride
-
The pure rotational spectra of five isotropic species of nitrosyl chloride were measured using a cavity pulsed microwave Fourier-transform spectometer.Some a-type transitions of all five isotopomers, and some weak b-type transitions of four of these isotopomers were measured in the 4-26 GHz frequency range.Precise values for the rotational constants and the quartic centrifugal distortion constants were obtained.The rotational constants were used in structure determinations and the centrifugal distortion constants were used in a refinement of the harmonic general valence force field.A harmonic central valence force field was also calculated.Hyperfine structure in these transitions arising from quadrupole and spin-rotation coupling interactions was also observed.Diagonal and off-diagonal quadrupole coupling constants and diagonal spin-rotation coupling constants of both the chlorine and nitrogen nuclei were determined.The principal quadrupole coupling constants were evaluated and used to calculate the approximate ionic character of the N-Cl bond.The spin-rotational coupling constants were used to calculate the diamagnetic shielding factor for the nitrogen nucleus; the magnitude of this value indicates a fairly ionic N-Cl bond.
- Gotehouse, Bethany,Meuller, Holger S. P.,Heineking, Nils,Gerry, Michael C. L.
-
p. 3347 - 3356
(2007/10/03)
-
- Reactions at a dimolybdenum(V) sulfur bridge: Metallothionitrites and the NO2-, NO, NO+ connection
-
Nitrosation of a dimetal bridge sulfur was observed for reactions of dimolybdenum(V) anions of the general form [Mo2(NAr)2(S2P(OEt)2) 2(μ-S)2(μ-O2CR)]- with ClNO (Cl15NO), NO+, NO2- (15NO2-), or i-C5H11ONO. The products were thionitrites containing the SNO- bridge ligand. The compounds were very reactive and underwent rapid nitrosyl migration reactions even at low temperatures. The migration resulted in overall oxo-for-imido exchange, after which additional processes ensued.
- Haub, Elaine K.,Lizano, Ana C.,Noble, Mark E.
-
p. 1440 - 1444
(2008/10/08)
-
- Ion-Molecule Reactions of Vibrationally State-Selected NO+ with Small Alkyl Halides
-
The effects of vibrational excitation in NO+ (v=0-5) on its reactivity with small alkyl halides (CnH2n+1X; n=1-3; X=Cl, Br, I) have been investigated under thermal translational conditions.The method combines resonance enhanced multiphoton ionization to form state-selected NO+(v), and Fourier transform in cyclotron resonance techniques to trap, react, and detect ions.Besides vibrational quenching of NO+(v > 0), which is found to be very efficient with alkyl halides, three reaction channels are observed: charge transfer, halide transfer, and CnH2nNO+ formation.Branching ratios and rate constants have been determined for the different channels as a function of the NO+(v=0) vibrationally energy.Endoergic charge transfer is efficiently driven by vibrational excitation.Halide transfer is the major channel if it is significantly exothermic for NO+(v=0).If this is not the case, adding vibrational energy in NO+(v=0) is only marginally effective in driving this channel.The data suggest that rearrangements in NO+-alkyl halide reaction intermediates and in carbonium ions are very rapid.The CnH2nNO+ formation channel is only observed with n-propyl and isopropyl chloride where it is dominant for NO+(v=0).Increasing vibrational excitation inhibits C3H6NO+ formation.The results are discussed in terms of possible reaction mechanisms.
- Wyttenbach, Thomas,Bowers, Michael T.
-
p. 8920 - 8929
(2007/10/02)
-
- Reaction of NO3 and N2O5 with Molecular Species of Possible Atmospheric Interest
-
The nitrate radical (NO3) has been shown to play an important role in nighttime tropospheric chemistry, particularly in polluted atmospheres.In order to understand more fully the role of NO3 in loss processes for various atmospheric species, a number of laboratory kinetic studies have been undertaken.Reported here are rate constant upper limits for the reaction of NO3 and N2O5 with HCl, ClNO, H2S, NH3, N2O, CH3CN, and CH4.Chemical reaction was observed in several of these systems (HCl, ClNO, H2S, and NH3), but possible heterogeneous (wall-catalyzed) reactions cannot be excluded.Possible mechanisms are presented for those cases where reaction occurred.In addition, studies of the reactions HCl + NO2, H2S + NO2, and Cl + HNO3 are also reported.The upper limits reported here rule out the reactions of NO3 or N2O5 in the gas phase as important removal processes for these species, but it is possible that the reaction of HCl with N2O5 catalyzed by aerosol surfaces may play an important role in linking the chemistry of the stratospheric odd nitrogen and odd chlorine cycles.
- Cantrell, C. A.,Davidson, J. A.,Shetter, R. E.,Anderson, B. A.,Calvert, J. G.
-
p. 6017 - 6021
(2007/10/02)
-
- On the trail of dichlorodinitrosyltungsten: A tale of two reactions
-
Polymeric [W(NO)2Cl2]n may be synthesized in high yields by two preparative methods. The first method involves treatment of WCl6 in CH2Cl2 with an excess of NO followed by complete purging of the ClNO byproduct from the system. It has been established that this reductive nitrosylation proceeds via the isolable intermediate complexes, dark violet cis-W(NO)2Cl4 and bright green fac-W(NO)3Cl3. The second method involves controlled reaction of W(CO)6 with 2 equiv of ClNO in CH2Cl2 after initiation of the conversion with traces of an oxidant. Evidence is presented that this reaction probably proceeds via a catalytic, radical chain mechanism, the initiation step being the formation of substitutionally labile W(CO)6+· and the final propagation step being the reduction of W(NO)2Cl2+· by W(CO)6, which affords the final product and regenerates W(CO)6+·. If either synthesis is effected in the presence of 2 equiv of CH3CN, the only nitrosyl-containing product formed is yellow-green W(NO)Cl3(CH3CN)2, a solid complex also obtainable by reaction of W(NO)2Cl4 or W(NO)3Cl3 with CH3CN. A variety of hard and soft Lewis bases, L, cleave polymeric [W(NO)2Cl2]n to produce new, monomeric W(NO)2Cl2L2 compounds that can be isolated in good yields. The stereochemistries of these octahedral complexes can generally be established by conventional spectroscopic methods. The complexes having L = THF, Et2O, or CH3CN undergo metathesis with n-Bu3Sn(C5H5) to form the known (η5-C5H5)W(NO)2Cl in moderate yields.
- Hunter, Allen D.,Legzdins, Peter
-
p. 4198 - 4204
(2008/10/08)
-
- The reaction of fluorosulfuryl isocyanate with alkali metal fluorides
-
Fluorosulfuryl isocyanate reacts with cesium, potassium, and sodium fluorides in acetonitrile solvent at 25° to form stable, solid adducts having a molar ratio FSO2NCO: MF close to 1:1. Chemical and physical evidence indicates that these compounds may be formulated as the salts of fluoroformylfluorosulfurylimide, M+[N(SO2F)C(O)F]-.
- Roderiguez, Joseph A.,Noftle, Ronald E.
-
p. 1874 - 1877
(2008/10/08)
-