Spectroscopic sudies of the intracluster hydration reaction of NO2+

Cao, Yang; Choi, Jong Ho; Haas, Bernd Michael; Okumura, Mitchio

doi:10.1021/j100098a010

Cited by 32 publications

(57 citation statements)

References 3 publications

(9 reference statements)

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“…The IR spectrum of gaseous H2O-NO2 displays two bands assigned to H20 stretching, whose maxima differ by <50 cm-1 from those of H20. These, and other spectroscopic features, point to a distant and relatively weak coordination of the monomers in the H2O-NO' complex (27,30), consistent with the theoretical results. The same picture is outlined by ab initic studies of the gaseous complexes formed by NO' with HCIO (24) and CH30H (8) and of the complexes containing two 'ligands-e.g.,' the H2O-(NO')-OH2 cation (7), characterized as a weakly bound complex, consistent with the evidence from IR and photodissociation spectroscopy (27,30).…”

Section: Methodssupporting

confidence: 86%

“…These, and other spectroscopic features, point to a distant and relatively weak coordination of the monomers in the H2O-NO' complex (27,30), consistent with the theoretical results. The same picture is outlined by ab initic studies of the gaseous complexes formed by NO' with HCIO (24) and CH30H (8) and of the complexes containing two 'ligands-e.g.,' the H2O-(NO')-OH2 cation (7), characterized as a weakly bound complex, consistent with the evidence from IR and photodissociation spectroscopy (27,30). In summary, the available structural evidence underlines the reluctance of the nitronium ion to form tightly bound complexes undergoing the necessary structural changes, in particular as concerns the deformation of its geometry.…”

Section: Methodssupporting

confidence: 86%

“…The spectra were recorded at temperatures ranging from 400 to 50°C, as measured by a thermocouple inserted into the source block, using gaseous mixtures of NO2 and the two ligands (L1 and L2), whose composition was optimized to obtain the highest intensity of the L1(NO')L2 dimers, at total pressures in the 0.1-to 0. The study of the complexes formed in the gas phase by NO2 is currently the focus of considerable fundamental interest (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11) and, in addition, has a direct bearing on areas ranging from mechanistic organic chemistry (12)(13)(14)(15)(16)(17)(18)(19) to atmospheric chemistry, clustering and nucleation phenomena, intracluster reactivity (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), etc. In view of the considerable interest of the problem and of the scant experimental information currently available (31-33), we have undertaken a systematic study of the binding energy (BE) of NO+ to representative ligands, aimed at the construction of a gas-phase nitronium ion-affinity scale.…”

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confidence: 99%

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Gas-phase nitronium ion affinities.

Cacace

Petris

Pepi

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

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Evaluation of nitronium ion-transfer equilibria, L1NO' + L2 = L2NO' + L1 (where L1 and L2 are ligands 1 and 2, respectively) by Fourier-transform ion cyclotron resonance mass spectrometry and application of the kinetic method, based on the metastable fragmentation of L1(NO+)L2 nitronium ion-bound dimers led to a scale of relative gas-phase nitronium ion affinities. ligands, aimed at the construction of a gas-phase nitronium ion-affinity scale.To this end, we have applied the Fourier-transform ion cyclotron resonance mass spectroscopy equilibrium method largely used in proton affinity (PA) measurements (34) to NO' transfer reactions and extended the kinetic method, so far used exclusively in PA and gas-phase acidity determinations (35,36), to nitronium ion-bound dimers. MATERIALS AND METHODSAll chemicals were obtained as research-grade products from Aldrich and were used without further purification. The gases were purchased from Matheson with a stated purity >99.95 mol %, except NO2, for which purity was >99.5 mol %, and were used L,NO+ + L2 = L2NO2 + Ll, [1] allows direct determination of the corresponding free energy change, AG', provided that the equilibrium constant can be accurately measured, which requires attainment of true equilibrium, unperturbed by significant side reactions. In the specific application, CH3O(NO2)2, the nitrating reagent, is prepared in the external chemical ionization source of a Fourier transform ion cyclotron resonance mass spectrometer and driven into the resonance cell, where it nitrates both ligands, present in a known concentration ratio. One of the nitrated complexes is isolated by selective-ejection techniques and allowed to equilibrate in the mixture of the ligands. Application of the method is prevented in many cases by incursion of fast proton-transfer reactions that perturb the equilibrium-e.g., the nitronium ion transfer, [C2H5OH-NO2]+ + NH3 = [H3N-NO2]+ + C2H5OH, [la] undergoes competition by proton transfer to ammonia from both nitrated complexes, which react as the conjugate acids of ethyl nitrate and of nitramide. Furthermore, in the case of ligands of low ionization potential the study of equilibrium 1 Abbreviations: PA, proton affinity; BE, binding energy; RP, reference pair; MIKE, mass analyzed ion kinetic energy. tTo whom reprint requests should be addressed.The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. 8635

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Section: Methodssupporting

confidence: 86%

Section: Methodssupporting

confidence: 86%

mentioning

confidence: 99%

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Gas-phase nitronium ion affinities.

Cacace

Petris

Pepi

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

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“…Experimental studies [114][115][116][117][118] have shown that, in the gas phase, this conversion of NO 2 + to HNO 3 occurs in clusters of NO 2 + with four or more water molecules.…”

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confidence: 99%

The heterogeneous hydrolysis of NO2 in laboratory systems and in outdoor and indoor atmospheres: An integrated mechanism

Finlayson-Pitts

Wingen

Sumner

et al. 2002

Phys. Chem. Chem. Phys.

621

767

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The heterogeneous reaction of NO 2 with water on the surface of laboratory systems has been known for decades to generate HONO, a major source of OH that drives the formation of ozone and other air pollutants in urban areas and possibly in snowpacks. Previous studies have shown that the reaction is first order in NO 2 and in water vapor, and the formation of a complex between NO 2 and water at the air-water interface has been hypothesized as being the key step in the mechanism. We report data from long path FTIR studies in borosilicate glass reaction chambers of the loss of gaseous NO 2 and the formation of the products HONO, NO and N 2 O. Further FTIR studies were carried out to measure species generated on the surface during the reaction, including HNO 3 , N 2 O 4 and NO 2 + . We propose a new reaction mechanism in which we hypothesize that the symmetric form of the NO 2 dimer, N 2 O 4 , is taken up on the surface and isomerizes to the asymmetric form, ONONO 2 . The latter autoionizes to NO + NO 3 À , and it is this intermediate that reacts with water to generate HONO and surface-adsorbed HNO 3 . Nitric oxide is then generated by secondary reactions of HONO on the highly acidic surface. This new mechanism is discussed in the context of our experimental data and those of previous studies, as well as the chemistry of such intermediates as NO + and NO 2 + that is known to occur in solution. Implications for the formation of HONO both outdoors and indoors in real and simulated polluted atmospheres, as well as on airborne particles and in snowpacks, are discussed. A key aspect of this chemistry is that in the atmospheric boundary layer where human exposure occurs and many measurements of HONO and related atmospheric constituents such as ozone are made, a major substrate for this heterogeneous chemistry is the surface of buildings, roads, soils, vegetation and other materials. This area of reactions in thin films on surfaces (SURFACE ¼ Surfaces, Urban and Remote: Films As a Chemical Environment) has received relatively little attention compared to reactions in the gas and liquid phases, but in fact may be quite important in the chemistry of the boundary layer in urban areas.

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“…Among many relevant examples one can cite the "Crafts-Friedel" reaction, namely the electrophilic alkylation process taking place in long-lived ion-molecule complexes formed upon addition of arenium ions to olefins, whose occurrence had long been predicted, but which has been demonstrated only very recently by exploiting the special features of the gaseous reaction environment (8). Other significant examples are the ion-molecule reactions within mixed [(H,O)nHNO,NO,'] clusters, of great relevance to atmospheric chemistry (9), and the S,2 reactions within ionized halobenzene-ammonia and halobenzene-methanol clusters (7). Another application of considerable interest to the problem of enantiomeric recognition and differentiation is related to ionic reactions in gaseous clusters formed by chiral molecules, currently studied by laser-induced fluorescence-excitation techniques (10).…”

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confidence: 99%