Electron ionization induced fragmentation of macrocyclic amines CnH2n−1NH2: Evidence for the rearrangement of aminocarbene radical cations and a comparison with long-chain esters

Mollova, Nevena; Longevialle, Pierre

doi:10.1016/1044-0305(90)85041-j

Cited by 12 publications

(4 citation statements)

References 15 publications

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“…After EI, cyclic C5 amines, as can be formed via the reactions proposed above, typically fragment via ring-opening α cleavage followed by H rearrangement [47]. The EI-MS of 2, 3, or 4, however, has not been reported to the best of our knowledge.…”

Section: Scheme 2 Possible Radical Substitution and Addition Reactiomentioning

confidence: 99%

Combined Ammonia and Electron Processing of a Carbon-Rich Ruthenium Nanomaterial Fabricated by Electron-Induced Deposition

et al. 2020

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Ammonia (NH3)-assisted purification of deposits fabricated by focused electron beam-induced deposition (FEBID) has recently been proven successful for the removal of halide contaminations. Herein, we demonstrate the impact of combined NH3 and electron processing on FEBID deposits containing hydrocarbon contaminations that stem from anionic cyclopentadienyl-type ligands. For this purpose, we performed FEBID using bis(ethylcyclopentadienyl)ruthenium(II) as the precursor and subjected the resulting deposits to NH3 and electron processing, both in an environmental scanning electron microscope (ESEM) and in a surface science study under ultrahigh vacuum (UHV) conditions. The results provide evidence that nitrogen from NH3 is incorporated into the carbon content of the deposits which results in a covalent nitride material. This approach opens a perspective to combine the promising properties of carbon nitrides with respect to photocatalysis or nanosensing with the unique 3D nanoprinting capabilities of FEBID, enabling access to a novel class of tailored nanodevices.

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Section: Scheme 2 Possible Radical Substitution and Addition Reactiomentioning

confidence: 99%

Combined Ammonia and Electron Processing of a Carbon-Rich Ruthenium Nanomaterial Fabricated by Electron-Induced Deposition

et al. 2020

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“…15,16 The site specificity of this H transfer in the loss of alkane is further confirmed by the MIKE (mass-analyzed ion kinetic energy) spectra of large ring cycloalkylamines. [17][18][19] After a-cleavage, cyclohexadecylamine, for example, rapidly isomerizes into an ionized long chain terminal enamine, as ionized enamines are very stable structures in the gas phase. 20 However a significant mechanistic difference exists between the ions reacting in the source and those reacting in the field-free region (FFR) of the instrument 17 (Scheme 2).…”

Section: Resultsmentioning

confidence: 99%

Further arguments concerning a ‘rotational effect’ in the unimolecular fragmentations of organic ions in the gas phase

Longevialle¹,

Lefèvre²,

Mollova

et al. 1998

Rapid Commun. Mass Spectrom.

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Further arguments are proposed to show that the 'size effect' observed in the competition between acleavages, as well as in the competition between losses of alkyl and alkane from aliphatic amines, can be interpreted as a 'rotational effect'. # 1998 John Wiley & Sons, Ltd. Received 3 November 1997; Revised 19 November 1997; Accepted 20 November 1997 Rapid Commun. Mass Spectrom. 12, 57-60 (1998 It has been now widely recognized that, in the unimolecular decomposition of isolated organic ions, the incipient ion (I) and neutral (N) fragments, before separation, can mutually reorientate while remaining electrostatically associated by ion-neutral interaction.1-12 It has been proposed that a critical energy (a so-called 'I-N reorientation threshold'), above which the two fragments can separately rotate is associated with this process. I-N reorientation may open to the parent ion new reaction pathways not accessible from the original structure, otherwise it is only a prelude to simple decomposition. In any case, when ion-neutral reorientation is irreversible it is a crucial event because, as a consequence, the fate of a given parent ion is actually decided as soon as incipient ion and neutral fragments have started mutual reorientation. Thus, the competition between reactions may be governed not only by their relative decomposition critical energies, but also by their respective reorientation critical energies.11,12 Therefore, the investigation of the factors that can influence the reorientation of incipient ionic and neutral fragments is important.Two effects have been shown 11,12 to play a significant role in this matter: an electrostatic effect and a rotational effect.When the neutral contains a permanent dipole, ionneutral reorientation leads to a more or less stable reoriented structure in which the charge-dipole distance is minimized and whose stabilization energy may be estimated, given an ion-dipole distance, as a function of the dipole moment and the polarizability of the neutral. When the neutral has no permanent dipole, only the contribution involving the polarizability is efficient in the electrostatic effect. In particular for a homologous series of neutrals the polarizability increases with the size. In both cases, the reorientation critical energy normally obeys the Marcus rule, 13 i.e. reorientation is more facile when leading to a more stable product.A rotational effect is expected when the initial rotational energy of the parent ion and the translational energy of separation of the incipient fragments participate in the relative rotational motion of the latter. These contributions also depend on the size of the fragments and may overshadow the participation of polarizability in the electrostatic effect.Some examples of the rotational effect have been described in the electron induced fragmentation of low energy alkanes 14 and aliphatic amines. 11,12 Further arguments may now be proposed that confirm the important role played by the individual rotation of the fragments during ion-neutral separation. RE...

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“…Therefore, grasping the ionization equilibrium of the amines is the foundation of studying these complex natural products. The alkalinity constant, commonly known as the p K b value, is a fundamental physical–chemical property in assessing the physiological action of majority medicine 1–10. Generally, the alkalinity of amines is described by the ionization equilibrium constant K b (or p K b ) of a typical response The definition of p K b is …”

Section: Introductionmentioning

confidence: 99%

A new method of accurate pK_b determinations for some organic amines

Jia¹,

Zhang²,

Zhou³

et al. 2007

Int J of Quantum Chemistry

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ABSTRACT:The accurate pK b determinations for some amines have been investigated using the combination of the extended clusters-continuum model with the polarizable continuum solvation model. The formation of molecular clusters by means of the amines wrapped up with water molecules leads to the weakness of the mutual function between the polar solvents and the amines, and, hence, the accuracy of pK b has been enhanced by using a coherent and well-defined approach without external approximations or experimental data. The calculations are performed at the HF/6-311ϩϩG(d, p) level and agreed well with experimental data because electron correlation effect cancels mutually in the calculated value of ⌬G which is not an absolute value, but a relative value. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem 108: [265][266][267][268][269][270][271] 2008

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Electron ionization induced fragmentation of macrocyclic amines C_nH_2n−1NH₂: Evidence for the rearrangement of aminocarbene radical cations and a comparison with long-chain esters

Cited by 12 publications

References 15 publications

Combined Ammonia and Electron Processing of a Carbon-Rich Ruthenium Nanomaterial Fabricated by Electron-Induced Deposition

Combined Ammonia and Electron Processing of a Carbon-Rich Ruthenium Nanomaterial Fabricated by Electron-Induced Deposition

Further arguments concerning a ‘rotational effect’ in the unimolecular fragmentations of organic ions in the gas phase

A new method of accurate pK_b determinations for some organic amines

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Electron ionization induced fragmentation of macrocyclic amines CnH2n−1NH2: Evidence for the rearrangement of aminocarbene radical cations and a comparison with long-chain esters

Cited by 12 publications

References 15 publications

Combined Ammonia and Electron Processing of a Carbon-Rich Ruthenium Nanomaterial Fabricated by Electron-Induced Deposition

Combined Ammonia and Electron Processing of a Carbon-Rich Ruthenium Nanomaterial Fabricated by Electron-Induced Deposition

Further arguments concerning a ‘rotational effect’ in the unimolecular fragmentations of organic ions in the gas phase

A new method of accurate pKb determinations for some organic amines

Contact Info

Product

Resources

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Electron ionization induced fragmentation of macrocyclic amines C_nH_2n−1NH₂: Evidence for the rearrangement of aminocarbene radical cations and a comparison with long-chain esters

A new method of accurate pK_b determinations for some organic amines