Penning ionization electron spectroscopy of monohalobenzenes: fluorobenzene, chlorobenzene, bromobenzene, and iodohenzene

Fujisawa, Shoji; Ohno, Koichi; Masuda, S.; Harada, Yoshiya

doi:10.1021/ja00281a010

Cited by 50 publications

(46 citation statements)

References 4 publications

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“…For the presented reaction mechanism, the BSSE would not change the results in any case. With these conditions, the absolute errors of the computed ionization energies for fluoro-, chloro-, bromo-, and iodobenzene were within 3% compared with experimental values given by Fujisawa et al [38]. Similarly, errors of the presented energy calculations are expected to be within the same range.…”

Section: Computational Calculationssupporting

confidence: 76%

Nucleophilic Aromatic Substitution Between Halogenated Benzene Dopants and Nucleophiles in Atmospheric Pressure Photoionization

Kauppila

Haack

Kroll

et al. 2015

J. Am. Soc. Mass Spectrom.

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Abstract. In a preceding work with dopant assisted-atmospheric pressure photoionization (DA-APPI), an abundant ion at [M + 77] + was observed in the spectra of pyridine and quinoline with chlorobenzene dopant. This contribution aims to reveal the identity and route of formation of this species, and to systematically investigate structurally related analytes and dopants. Compounds containing N-, O-, and S-lone pairs were investigated with APPI in the presence of fluoro-, chloro-, bromo-, and iodobenzene dopants. Computational calculations on a density functional theory (DFT) level were carried out to study the reaction mechanism for pyridine and the different halobenzenes. The experimental and computational results indicated that the [M + 77] + ion was formed by nucleophilic aromatic ipso-substitution between the halobenzene radical cation and nucleophilic analytes. The reaction was most efficient for N-heteroaromatic compounds, and it was weakened by sterical effects and enhanced by resonance stabilization. The reaction was most efficient with chloro-, bromo-, and iodobenzenes, whereas with fluorobenzene the reaction was scarcely observed. The calculated Gibbs free energies for the reaction between pyridine and the halobenzenes were shown to increase in the order I < Br < Cl < F. The reaction was found endergonic for fluorobenzene due to the strong C-F bonding, and exergonic for the other halobenzenes. For fluoro-and chlorobenzenes the reaction was shown to proceed through an intermediate state corresponding to [M + dopant] + , which was highly stable for fluorobenzene. For the bulkier bromine and iodine, this intermediate did not exist, but the halogens were shown to detach already during the approach by the nucleophile.

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Section: Computational Calculationssupporting

confidence: 76%

Nucleophilic Aromatic Substitution Between Halogenated Benzene Dopants and Nucleophiles in Atmospheric Pressure Photoionization

Kauppila

Haack

Kroll

et al. 2015

J. Am. Soc. Mass Spectrom.

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“…19 In the case of molecular adsorbates, the DOS is governed by the molecular orbitals, which cansdepending on the interaction of the adsorbate with its environmentsbe modified from the isolated state in the gas phase. Literature data of the benzene derivatives in the gas phase investigated by UPS are available for bromobenzene 20 and nitrobenzene. 21 In Figure 5, these gas phase He I spectra are compared to UPS spectra of the solid adsorbate layers of nitro-and bromobenzene, excited with He I and He II radiation, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The emission feature a or a 1 is the highest occupied molecular orbital (HOMO) and consists of a π 2 or π 3 state (a 1 or b 2 symmetry) for nitro-and bromobenzene, respectively. 20,21 The emission structure c corresponds to the π 1 orbital. The emission features d 1 /d 2 and e involve σ-bond-derived molecular orbitals predominantely on the benzene rings.…”

Section: Resultsmentioning

confidence: 99%

Electronic Structure of Methoxy-, Bromo-, and Nitrobenzene Grafted onto Si(111)

et al. 2006

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The properties of Si(111) surfaces grafted with benzene derivatives were investigated using ultraviolet photoemission spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). The investigated materials were nitro-, bromo-, and methoxybenzene layers (-C 6 H 4 -X, with X ) NO 2 , Br, O-CH 3 ) deposited from diazonium salt solutions in a potentiostatic electrochemical process. The UPS spectra of the valence band region are governed by the molecular orbital density of states of the adsorbates, which is modified from the isolated state in the gas phase due to molecule-molecule and molecule-substrate interaction. Depending on the adsorbate, clearly different emission features are observed. The analysis of XPS intensities clearly proves multilayer formation for bromo-and nitrobenzene in agreement with the amount of charge transferred during the grafting process. Methoxybenzene forms only a sub-monolayer coverage. The detailed analysis of binding energy shifts of the XPS emissions for determining the band bending and the secondary electron onset in UPS spectra for determining the work function allow one to discriminate between surface dipole layerss changing the electron affinitysand band bending, affecting only the work function. Thus, complete energy band diagrams of the grafted Si(111) surfaces can be constructed. It was found that silicon surface engineering can be accomplished by the electrochemical grafting process using nitrobenzene and bromobenzene: siliconderived interface gap states are chemically passivated, and the adsorbate-related surface dipole effects an increase of the electron affinity.

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“…In substituted benzenes, the first lowest-energy band, is still apparent, but frequently it is broadened (e.g., as in C 6 H 5 F [31] and C 6 H 5 CH 3 [32] ) or split into two components (e.g., as in C 6 H 5 I [33] , C 6 H 5 NH 2 [34] , and C 6 H 5 OH [30] ). The gap of 1 eV between the first two bands in the spectrum of benzene is frequently occupied by one or more sharper peaks in the spectra of substituted benzenes (e.g., as in C 6 H 5 I [33] and C 6 H 5 NH 2 [34] ). These peaks are derived from the ionization of electrons largely localized on lone pair-type orbitals.…”

Section: Spectral Assignmentmentioning

confidence: 99%

“…In this work we are interested in the complex interplay between the substituents in the three iodoanisoles, as Figure 7 Correlation diagram of the experimentally determined vertical ionization potentials of C 6 H 6 [30] , C 6 H 5 I [33] , o-, m-, p-IC 6 H 4 OCH 3 and C 6 H 5 OCH 3 [35] . monitored by the measured ionization potentials pertaining to well-resolved π and n lone pair bands, and the relative reactivity effects.…”

Section: Substituent Effectsmentioning

confidence: 99%

Electron structure and substituent effects in o-, m-, p-IC6H4OCH3 iodoanisoles

Tong

Wang

et al. 2009

Sci. China Ser. B-Chem.

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The electronic structures and substituent effects in o-, m-, and p-iodoanisoles have been investigated by ultraviolet photoelectron spectroscopy (UPS). The observed UPS bands were analyzed by combining empirical arguments and theoretical methods. Owing to the electron-donating nature of both iodoand methoxy substituents, the first ionization potentials of the three iodoanisoles are lower than those of iodobenzene and anisole. The presence of the two substituents in iodoanisoles leads to an electronrich structure, which might contribute to the observed high reactivity of iodoanisoles in a number of organic reactions. electronic structures, substituent effects, ultraviolet photoelectron spectroscopy, reactivity

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Penning ionization electron spectroscopy of monohalobenzenes: fluorobenzene, chlorobenzene, bromobenzene, and iodohenzene

Cited by 50 publications

References 4 publications

Nucleophilic Aromatic Substitution Between Halogenated Benzene Dopants and Nucleophiles in Atmospheric Pressure Photoionization

Nucleophilic Aromatic Substitution Between Halogenated Benzene Dopants and Nucleophiles in Atmospheric Pressure Photoionization

Electronic Structure of Methoxy-, Bromo-, and Nitrobenzene Grafted onto Si(111)

Electron structure and substituent effects in o-, m-, p-IC6H4OCH3 iodoanisoles

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