Comparison of the zero-field pulsing technique and the ICR [ion cyclotron resonance] technique for studying ion-molecule reactions

Herod, Alan A.; Harrison, A. G.; O'Malley, Rebecca M.; Ferrer‐Correia, A. J.; Jennings, K. R.

doi:10.1021/j100707a023

Cited by 15 publications

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“…The reaction rate was found to fall off dramatically after the third and fourth additions, which was attributed to steric effects. Similar results obtained by various other experimental methods applied to the study of a number of different systems led the investigators to suggest that gas phase cationic polymerization is responsible for the occurrence of the high molecular weight ions. − …”

Section: Introductionmentioning

confidence: 53%

“…Similar results obtained by various other experimental methods applied to the study of a number of different systems led the investigators to suggest that gas phase cationic polymerization is responsible for the occurrence of the high molecular weight ions. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Meanwhile, considerable effort has been devoted to the investigation of these ion-molecule reactions in the cluster regime [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] as well. This has been prompted by the recognition that interrogating clusters provides a way of studying the energetics and dynamics of intermediate states of matter as cluster systems evolve from the gas toward the condensed state.…”

Section: Introductionmentioning

confidence: 99%

“…Gas phase ion−molecule reactions involving systems of unsaturated hydrocarbons and their derivatives have been the subject of many investigations, spanning several decades. Many different experimental techniques have been utilized, including photolysis, radiolysis, , high-pressure mass spectrometry, − tandem quadruple MS/MS, and ion cyclotron resonance. − In a high-pressure MS experiment in ethene, , Kebarle and co-workers observed that an increase in the concentration of ethene in the ion source led to large increases in the intensities of intermediate size C 2 n H 4 n + with n = 4−5 and the disappearance of smaller ions with n = 1−3. This effect was explained by invoking the occurrence of association reactions of ethene molecules.…”

Section: Introductionmentioning

confidence: 99%

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Intracluster Polymerization Reactions of Alkene Cluster Ions

et al. 1997

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The unimolecular dissociation dynamics of selected alkene cluster ions (ethene, propene, 1-butene, trans-2butene, and cis-2-butene) and their fast fragment ions has been investigated using a reflectron time-of-flight mass spectrometer. These ions were prepared by the supersonic expansion of a premixed sample gas containing 20% alkene in Ar, followed by multiphotoionization (MPI) using a Ti:sapphire femtosecond laser. From the unimolecular decomposition patterns of all the ions investigated, we conclude that after photoionization a radical cation initiated intracluster polymerization takes place in these cluster ions. But, due to steric hindrance, it does not continue indefinitely as the cluster size increases. For ethene, pentamerization can be observed, and for propene, trimerization; while in the case of the three isomeric butenes, 1-butene is partially trimerized and only dimerization is observed in 2-butene.

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Section: Introductionmentioning

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intracluster Polymerization Reactions of Alkene Cluster Ions

et al. 1997

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“…52,58 At low pressures the reaction of C 3 H 6 •+ with C 3 H 6 yielded C 4 H 8 •+ (43%), C 3 H 7 + (24%), C 5 H 9 + (20%), and C 4 H 7 + (13%) with an overall rate coefficient of 7.4 × 10 -10 cm 3 s -1 . 48,49,55,57 At higher pressures (0.25 Torr), the dimer cation was observed, although not at a very significant yield. 49 The covalent nature of the dimer has been suggested on the basis of the proposed structures by Futurell 49 52 When C 6 H 12 •+ has an olefinic structure, a condensation process occurs to produce C 9 H 18 •+ , and higher order products may be expected.…”

Section: Resultsmentioning

confidence: 95%

“…For example, the reactions of C 3 H 6 •+ with neutral C 3 H 6 involve several channels starting with the formation of the C 3 H 7 + , C 4 H 7 + , and C 4 H 8 •+ ions and their association products. Although several groups have investigated the ion/molecule reactions of propene, [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59] the formation of higher order condensation products (C 3 H 6 ) n •+ with n > 2 in the gas phase has not been reported. Interestingly, intracluster polymerization leading to covalently bonded molecular ions has been proposed to explain the ion distribution resulting from the electron impact ionization of propene clusters.…”

Section: Introductionmentioning

confidence: 99%

Gas-Phase Oligomerization of Propene Initiated by Benzene Radical Cation

Pithawalla¹,

Meot‐Ner²,

Gao³

et al. 2001

J. Phys. Chem. A

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Initiation of the radical cation polymerization of propene has been observed following the selective ionization of benzene in the gas phase by resonance two-photon ionization−high-pressure mass spectrometry (R2PI−HPMS) and by selected ion flow tube (SIFT) techniques. In this system, the aromatic initiator (C6H6) has an ionization potential (IP) between those of the reactant's monomer (C3H6) and its covalent dimer (C6H12), i.e, IP(C3H6) > IP(C6H6) > IP(C6H12). Therefore, direct charge transfer from C6H6 •+ to C3H6 is not observed due to the large endothermicity of 0.48 eV, and only the adduct C6H6 •+(C3H6) is formed. However, coupled reactions of charge transfer with covalent condensation are observed according to the overall process C6H6 •+ + 2C3H6 → C6H12 •+ + C6H6, which results in the formation of a hexene product ion, C6H12 •+. The formation of this ion can make the overall process of charge transfer and covalent condensation significantly exothermic. At higher concentrations of propene, the reaction products are the propene oligomers (C3H6) n •+ with n = 2−7 and the adduct series C6H6 •+(C3H6) n with n ≤ 6. The significance of the coupled reactions is that the overall process leads exclusively to the formation of the condensation product (C3H6) n •+ and avoids other competitive channels in the ion/molecule reactions of propene. Gas-phase nominal second-order rate coefficients for the overall reaction into both channels are in the range of (1−3) × 10-12 cm3 s-1. The rate coefficients into both channels, especially for the formation of the C6H12 •+ dimer, have large negative temperature dependencies. Consistent with the gas-phase results, the intracluster reactions of C6H6 •+ produced selectively by R2PI of mixed benzene/propene clusters also do not form the monomer ion C3H6 •+ but form higher propene clusters (C3H6) n •+ that contain at least the C6H12 •+ hexene ion. The similarity of the reaction mechanisms in the gas phase and in preformed clusters suggests that the mechanism may also apply in the condensed phase in common aromatic solvents such as benzene and toluene.

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Ion Cyclotronc Resonance

Gray¹

1971

Advances in Chemical Physics

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Comparison of the zero-field pulsing technique and the ICR [ion cyclotron resonance] technique for studying ion-molecule reactions

Cited by 15 publications

References 0 publications

Intracluster Polymerization Reactions of Alkene Cluster Ions

Intracluster Polymerization Reactions of Alkene Cluster Ions

Gas-Phase Oligomerization of Propene Initiated by Benzene Radical Cation

Ion Cyclotronc Resonance

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