ELECTRON IMPACT SPECTROSCOPY OF TETRAMETHYLGERMANIUM, TRIMETHYLSILANE AND DIMETHYLMERCURY<sup>1</sup>

Hobrock, Brice G.; Kiser, Robert W.

doi:10.1021/j100807a035

Cited by 41 publications

(5 citation statements)

References 1 publication

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“…As far as mass 58 amu is concerned, the corresponding electron energy scan is shown in figure 10: two contributions can be observed, one with an appearance energy of 8.3±0.3 eV, which is not present when a shutter prevents the plasma beam from reaching the MS housing, and the other with an appearance energy of 10.2 ± 0.3 eV, whose intensity is not affected by the shutter insertion. According to the literature, the latter can be attributed to the Me 2 Si + originating from the dissociative ionization of Me 3 SiH [61] and Me 2 SiH 2 [62] molecules in the MS. The early appearance energy can be associated with a radical, SiMe 2 , or with the molecule, OSi=CH 2 .…”

Section: Ion-electron Dissociative Recombination Routesmentioning

confidence: 96%

On the hexamethyldisiloxane dissociation paths in a remote Ar-fed expanding thermal plasma

Creatore¹,

Barrell

Benedikt

et al. 2006

Plasma Sources Sci. Technol.

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In this paper we present primary hexamethyldisiloxane (HMDSO) molecule dissociation paths in a remote argon-fed expanding thermal plasma, where the HMDSO dissociation is initiated by charge exchange reactions with argon ions followed by dissociative recombination reactions with electrons. Investigation of the argon/HMDSO plasma chemistry by means of cavity ring down spectroscopy and threshold ionization mass spectrometry has allowed the detection and identification of radical species, such as CH x , SiC x H y and SiCH x O, and oligomerization products. The charge exchange reaction rate constant between argon ions and HMDSO molecules has been found to be equal to (4 ± 2) × 10 −16 m 3 s −1 . This reaction has a dissociative character, i.e. the dissociation occurring at the Si-C and Si-O bonds accompanied by the abstraction of radicals, e.g. CH 3 and OSi(CH 3 ) 3 . Under the experimental conditions investigated, the ions produced via charge exchange reactions lead to negligible ion-induced oligomerization routes. Instead, they undergo recombination reactions with electrons, leading to Si-O bond dissociation and further abstraction of methyl radicals.

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Section: Ion-electron Dissociative Recombination Routesmentioning

confidence: 96%

On the hexamethyldisiloxane dissociation paths in a remote Ar-fed expanding thermal plasma

Creatore¹,

Barrell

Benedikt

et al. 2006

Plasma Sources Sci. Technol.

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“…The possible presence of CH 3 HgCH 3 was ruled out due to the absence of CH 3 Hg 1 cluster. 30 However, the low levels of the mercury preclude unambiguous identification in such a manner. The natural occurrence of CH 3 HgH in the head space of B. juncea appears to be unlikely as it is an intermediate (half-life of approximately 2 h) in the reduction reaction (by means of NaBH 4 ) of alkylmercury species to elemental mercury.…”

Section: Volatile Forms Of Mercury and Seleniummentioning

confidence: 99%

Localization and speciation of selenium and mercury in Brassica juncea—implications for Se–Hg antagonism

Mounicou

Shah

Meija

et al. 2006

J. Anal. At. Spectrom.

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The occurrence and form of selenium and mercury were investigated in Indian Mustard, Brassica juncea, a selenium accumulating plant, which had been co-exposed to varying concentration levels of these two elements. Plants were grown and exposed in hydroponic solutions. Following exposure, root exudates were collected in fresh solutions and the head-space around the aerial portions of the plants was sampled. These samples and the harvested plant tissues were then processed for determination of Se and Hg-containing compounds. For the plant tissues, roots, stems and leaves were separated and extracted using a sequential procedure that removed watersoluble species, water-soluble proteins, and dodecyl sulfate-soluble proteins. Size exclusion chromatography allowed further fractionation. High molecular-weight selenium/mercurycontaining compounds were found primarily in the plant root extract. Evidence suggests that a Se and Hg complex of high molecular weight may be protein associated. For the analysis of exudate solutions, ion-pairing reversed phase chromatography coupled to ICP-MS was used. Multiple selenium and mercury species were detected, with one mercury-containing compound observed eluting near selenocystine. Plant head-space was sampled with solid phase microextraction and analyzed with GC-ICP-MS and GC-TOFMS. Apart from the primary selenium volatiles and elemental mercury, no volatile species simultaneously containing Se and Hg could be detected.

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“…Theory predicts that silyl cations are stable, even more so than analogous carbocations, because of the larger size, polarizability, and electropositivity of silicon (2). Moreover, such species have been studied thoroughly in the gas phase (3), and recent studies have provided evidence for their existence as reactive intermediates (4). Many reports of direct observation of stable, long-lived silyl cations in condensed phase have been flawed (5) and continue to be controversial (6)(7)(8).…”

mentioning

confidence: 99%

Crystal Structure of a Silyl Cation with No Coordination to Anion and Distant Coordination to Solvent

Lambert

Zhang

Stern

et al. 1993

Science

334

237

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The crystal structure of a stable silyl cation, triethylsilylium, in the form of its tetrakis (pentafluorophenyl)borate salt [Et(3)Si(+) (C(6)F(5))(4)B(-)] (Et, ethyl) shows no coordination between cation and anion. The closest silicon-fluorine distance is greater than 4 angstroms. A toluene solvent molecule is close enough to cause some deviations from planarity at the silicon, but the silicon-toluene distance is well beyond the sum of the silicon and carbon covalent radii. The toluene molecule is essentially planar and undistorted, as expected if little or no positive charge has been transferred from silicon to toluene.

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ELECTRON IMPACT SPECTROSCOPY OF TETRAMETHYLGERMANIUM, TRIMETHYLSILANE AND DIMETHYLMERCURY¹

Cited by 41 publications

References 1 publication

On the hexamethyldisiloxane dissociation paths in a remote Ar-fed expanding thermal plasma

On the hexamethyldisiloxane dissociation paths in a remote Ar-fed expanding thermal plasma

Localization and speciation of selenium and mercury in Brassica juncea—implications for Se–Hg antagonism

Crystal Structure of a Silyl Cation with No Coordination to Anion and Distant Coordination to Solvent

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ELECTRON IMPACT SPECTROSCOPY OF TETRAMETHYLGERMANIUM, TRIMETHYLSILANE AND DIMETHYLMERCURY1

Cited by 41 publications

References 1 publication

On the hexamethyldisiloxane dissociation paths in a remote Ar-fed expanding thermal plasma

On the hexamethyldisiloxane dissociation paths in a remote Ar-fed expanding thermal plasma

Localization and speciation of selenium and mercury in Brassica juncea—implications for Se–Hg antagonism

Crystal Structure of a Silyl Cation with No Coordination to Anion and Distant Coordination to Solvent

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ELECTRON IMPACT SPECTROSCOPY OF TETRAMETHYLGERMANIUM, TRIMETHYLSILANE AND DIMETHYLMERCURY¹