[C6H6iso-C3H7+] and [C6H7+C3H6] ion-molecule complexes: theoretical calculations

Berthomieu, Dorothée; Brenner, V.; Ohanessian, Gilles; Denhez, J. P.; Millié, P.; Audier, H. E.

doi:10.1021/ja00059a055

Cited by 31 publications

(27 citation statements)

References 2 publications

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“…The reactions of protonated alkyl benzenes include alkane elimination. This process involves C-C cleavage to a complex 93,94 comprising an alkyl cation and a neutral aromatic species, followed by abstraction of a benzylic hydrogen atom by the alkyl cation (Scheme 20). [94][95][96][97] Indeed, protonated 1-(4-t-butylphenyl)-3-phenylpropane eliminates butane in which the tenth hydrogen atom has been acquired exclusively and at equal rates from either the near or remote benzylic position, thus demonstrating that the t-butyl cation moves freely relative to its 1,3-diphenylpropane partner.…”

Section: Alkane Eliminations From Protonated Alkylbenzenesmentioning

confidence: 99%

“…The products arising from dissociation of protonated dialkylbenzenes were compared to those formed from the analogous complexes produced by the combination of a tbutyl cation with the appropriate alkylbenzene. 93,94 Thus, the products obtained after combination of a t-butyl cation with n-, sec-and t-butyl substituted benzenes gave very similar mass-analysed ion kinetic energy (MIKE) spectra, which were dominated by butane elimination involving transfer of a benzylic hydrogen atom. There was no interchange of butyl groups in the reactions of these species, so complexes containing a t-butyl cation are exclusively formed.…”

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confidence: 98%

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EMS Account: Alkane eliminations from ions in the gas phase

McAdoo

Bowen

1999

Eur. J. Mass Spectrom.

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A review of reactions involving the elimination of an alkane from a variety of even and odd electron ions in the gas phase is presented. Particular attention is focused on the mechanisms of these reactions and the role of ion-neutral complexes. Alkane eliminations from open shell species derived by ionisation of ketones, ethers, alcohols, amines, alkanes and alkyl-substituted cycloalkanes are considered, together with ethane loss from the distonic ion CH 2 =O + CH 2 CH 2 •. These reactions are, without obvious exception, complex-mediated. Elimination of alkanes from an assortment of closed shell ions, including protonated acetaldehyde, dialkylmethylene immonium ions, onium ions, quaternary ammonium cations, alkoxide anions, enolate anions and deprotonated amines are also discussed. These reactions tend to be complex-mediated when heterolytic bond cleavages are possible. When such cleavages are not energetically feasible, alkane eliminations can take place by asynchronous, concerted mechanisms. Several factors affect the relative rates of alkane elimination compared to those of competing alkyl radical loss in the dissociations of these radical-cations; these factors include the internal energy of the ion, the size of the ionic and neutral partners, the initial orientation of these components and the binding energy of the complex. In addition, primary and secondary isotope effects influence both alkyl radical and alkane elimination. When alkanes are eliminated from radical-cations, reaction between the partners is often quickly overtaken in importance by direct separation of the components if the internal energy is raised either by increasing the energy of the ionisation process or by prior isomerisation over an energy barrier. This trend demonstrates that the attractions between the partners are easily overcome by quite small amounts of excess energy in the system. Typical binding energies between the ionic and non-polar neutral partners lie in the range 0-30 kJ mol-1 at distances at which covalent forces cease to be significant. Illustrative examples are given to show how studies of reactions involving ion-neutral complexes offer a means of obtaining information on the dynamics of short range interactions between ions and neutrals, including the motions of the partners relative to each other.

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Section: Alkane Eliminations From Protonated Alkylbenzenesmentioning

confidence: 99%

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confidence: 98%

EMS Account: Alkane eliminations from ions in the gas phase

McAdoo

Bowen

1999

Eur. J. Mass Spectrom.

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“…This method has atready been successfully applied to complexes composed of perylene or anthracene-X complexes (where X may be benzene, phenol, aniline, N-methylaniline or N,N-dimethylaniline) [3]. More recently, it has been used to explain the stability of small doubly charged paradifluorobenzene clusters [4], to demonstrate, for the first time, the stability of the ion-molecule complexes [C6H6 iso-C3H~] and [C6H ~ C3H6] [5] and to determine the structures of isomers observed in the excitation spectrum of l(2)cyanonaphthalene clustered with acetonitrile and water [6]. At second order, the interaction energy is obtained as a sum of four terms: electrostatic, polarization, dispersion and short range repulsion.…”

Section: Introductionmentioning

confidence: 99%

Intermolecular interactions: basis set and intramolecular correlation effects on semiempirical methods. Application to (C2H2)2, (C2H2)3 and (C2H4)2

Brenner

Millié

1994

Z Phys D - Atoms, Molecules and Clusters

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Abstract.A detailed study of the intrinsic consistency of the semiempirical method of P. Claverie namely, the effects of the basis set and intramolecular correlation on the multipole distributions of molecular subunits and the influence of the electronic population of each atom in the molecular subunit on its van der Waals radius, is performed on some van der Waals dimers. The validity, limits of this model and the appropriate way to use it is established. In particular, the dependence of the geometry and the interaction energy on the basis set chosen and the intramolecutar correlation shows that the multipole distribution involved in the calculation of the electrostatic and polarization terms must be derived from a correlated wave function within an extended basis set. Associated to non local methods for finding stationary points, the method of P. Claverie reproduce reliably the intermolecular geometrical parameters observed for the equilibrium structures and the transition states of the dimer and trimer of acetylene. In addition, a study of the equilibrium structures of the ethylene dimer is presented, the aim of being to clarify the considerable uncertainty in their number and their geometry.

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“…[1][2][3][4][5][6][7][8][9] To bring further information on this subject, we have studied the possible existence of a stable (i.e., a local energy minimum state) complex between ethene and a benzenium ion. In this connection, we have encountered a case where the two commonly applied computation schemes, MP2 and density functional theory (DFT) represented by the B3LYP functional, are at variance.…”

Section: Introductionmentioning

confidence: 99%

Does an Ethene/Benzenium Ion Complex Exist? A Discrepancy between B3LYP and MP2 Predictions

Kolboe

Svelle

2008

J. Phys. Chem. A

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To investigate the possible existence of a complex between the benzenium ion and ethene, computations employing B3LYP and MP2 were carried out. The two methodologies gave conflicting answers; B3LYP confirmed the existence, but according to MP2, the structure found by B3LYP transforms into an ethylbenzenium ion. Computations utilizing the CCSD and QCISD methods showed the B3LYP result to be correct; 21 kJ/mol is needed to separate the two moieties.

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[C6H6iso-C3H7+] and [C6H7+C3H6] ion-molecule complexes: theoretical calculations

Cited by 31 publications

References 2 publications

EMS Account: Alkane eliminations from ions in the gas phase

EMS Account: Alkane eliminations from ions in the gas phase

Intermolecular interactions: basis set and intramolecular correlation effects on semiempirical methods. Application to (C2H2)2, (C2H2)3 and (C2H4)2

Does an Ethene/Benzenium Ion Complex Exist? A Discrepancy between B3LYP and MP2 Predictions

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