Gas phase reaction of methylene radicals with monosilane

Simons, J. W.; Mazac, C. J.

doi:10.1139/v67-279

Cited by 9 publications

(8 citation statements)

References 2 publications

(2 reference statements)

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“…The presence of a radical scavenger, butadiene or oxygen, eliminated products of triplet methylene reaction and reduced the levels of some higher silanes. These products have been detected previously in unscavenged reactions [6] and attributed to secondary reactions of silyl radicals with the methylsilane substrate [7].…”

Section: Productssupporting

confidence: 62%

The decomposition kinetics of chemically activated methyl‐d₁‐methylsilane‐d₂ and ethylsilane‐d₃

Richardson

Simons

1978

Int J of Chemical Kinetics

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The decomposition kinetics of chemically activated methyl-dl -methylsilane-dz (DMS-dj) and ethylsilane-d3 (ES-d;) from the Si-D and C-H insertion reactions of CH2 ('AJ with methylsilane-d3 have been studied. The total rate constants for decomposition of chemically activated DMS-dz and ES-d3 have been measured. The individual rate constants for molecular elimination of CHsD, CHzDz, and Dz from DMS-d; and for molecular elimination of CH3CHzD and Dz from ES-dl have been measured. All of the above rate constants exhibit the expected kinetic isotope effect when compared to those found previously in the undeuterated system. RRKM theory calculations of the rate constants for the expected C-Si and Si-D bond rupture processes, based on energetics and activated complex models deduced previously for the undeuterated system, were carried out. In the case of DMS-d; the RRKM theory calculations of rate constants for the bond rupture processes combined with experimental rate constants for the molecular elimination processes gave a total rate constant for decomposition in agreement with the measured value. The results of a high-pressure study of the CH3DKHzDz ratio from chemically activated DMS-d3 decomposition were consistent with complete randomization of internal energy up to a pressure of 4 atmospheres (lifetime of -1.7 X lo-" sec). This is not an unexpected result in light of earlier work.

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Section: Productssupporting

confidence: 62%

The decomposition kinetics of chemically activated methyl‐d₁‐methylsilane‐d₂ and ethylsilane‐d₃

Richardson

Simons

1978

Int J of Chemical Kinetics

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“….__* radicals scavenged by 02 (12) where nR = n-butane, IP = isopentane, nP = n-pentane, CB2 = cis-2-butene, CDMC = cis-1 ,&dimethyl-cyclopropane, TDMC = trans-1 ,2-dimethylcyclopropane, and the asterisk indicates excess vibrationalrotational energy above that required for isomerization. In order to determine the experimental rate constants for geometric isomerization, cis-2-butene-diazomethane-oxygen mixtures in the approximate ratios of 1 O : l : l were photolyzed at 3660 and 43Fi8 A over a large range of pressures.…”

Section: Resultsmentioning

confidence: 99%

Chemically activated cis-1,2-dimethylcyclopropane from photolysis of cis-2-butene-diazomethane mixtures in the presence of oxygen

Simons¹,

Taylor²

1969

J. Phys. Chem.

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Experimental evidence obtained in this study verifies reciprocal relations for two nonassociating ternary systems within the limits of experimental error. In addition, it demonstrates the applicability of hydrodynamic theory to multicomponent liquid diffusion. These conclusions are based on the fact that good agreement between the diffusion and phenomenological coefficients obtained by optical methods and those obtained from friction coefficients was found for the nonassociating systems studied.Hopefully experimental techniques will be developed in the future which will enable measurement of quaternary or higher diffusion coefficients, Dij, so that those calculated from friction coefficients, ui, can be checked. Since hydrodynamic theory requires fewer independent friction coefficients than independent diffusion coeficients to describe diffusion in systems of more than three components, such experimental techniques would be extremely valuable in checking the applicability of hydrodynamic theory to such systems.A study of the geometric and structural isomerization rates of chemically activated cis-1,2-dimethylcyclopropane formed by singlet methylene radical addition to the double bond of cis-2-butene is reported. The singlet methylene radicals were produced by diazomethane photolysis a t 4358 and 3660 d in the presence of added oxygen. The structural isomerization rate was determined by an internal comparison method that eliminates uncertainties due to pentene decomposition. The rates are in excellent agreement with RRKM theory calculations at an adjusted energy for each photolysis wavelength. The energies carried into the activated molecule by the methylene radical were 113.0 and 116.8 kcal/mol at 4358 and 3660 A, respectively. These values suggest that the methylene radical carries into the addition reaction a relatively small fraction (0.30) of the total excess energy available from its formation reaction. Energies determined in this work, applied to related systems, give results that differ by at most -3 kcal/moI from earlier determinations.

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“…[47][48][49] The rate of insertion into Si-H bonds in methylsilane is ca. 9 times faster than the insertion into the C-H bonds.…”

Section: Introductionmentioning

confidence: 99%

Photochemical Reaction of Diazomethane with Hydrogen-Terminated Silicon Surfaces

et al. 2001

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Diazomethane reacts with hydrogen-terminated porous or single crystal silicon surfaces under irradiation with the 365 nm line from a mercury lamp. The surface Si-H x groups are lost and an HF-resistant, polymeric hydrocarbon species is formed. The mechanism is proposed to commence with insertion of singlet methylene into the Si-H bond as in the analogous reaction of molecular hydrosilanes. However, the infrared spectra indicate that -CH 2 -groups rather than terminal -CH 3 are dominant on the surface after reaction. This is attributed to an oligomerization which may proceed via attack of singlet methylene on C-H bonds or via a radical process. In the case of porous silicon, significant oxidation occurs in parallel to the reaction with diazomethane due to the presence of trace water from the reagents used to generate diazomethane. The oxidized silicon species can, however, be removed selectively by washing in aqueous 48% HF without affecting the integrated intensity of the C-H stretching bands observed by FTIR spectroscopy. In combination with an analysis of the IR spectroscopic data, we conclude that the hydrocarbon species on the surface are anchored via robust Si-C bonds rather than the labile Si-O-C linkage. This is further supported by the stability of diazomethane-treated, polished single crystal wafers to in-air STM and electrochemical cycling in aqueous media. The diazomethane treatment also shifts the flatband potential in a negative direction in aqueous NaCl compared to Si(111)-H surfaces.

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Gas phase reaction of methylene radicals with monosilane

Cited by 9 publications

References 2 publications

The decomposition kinetics of chemically activated methyl‐d₁‐methylsilane‐d₂ and ethylsilane‐d₃

The decomposition kinetics of chemically activated methyl‐d₁‐methylsilane‐d₂ and ethylsilane‐d₃

Chemically activated cis-1,2-dimethylcyclopropane from photolysis of cis-2-butene-diazomethane mixtures in the presence of oxygen

Photochemical Reaction of Diazomethane with Hydrogen-Terminated Silicon Surfaces

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Gas phase reaction of methylene radicals with monosilane

Cited by 9 publications

References 2 publications

The decomposition kinetics of chemically activated methyl‐d1‐methylsilane‐d2 and ethylsilane‐d3

The decomposition kinetics of chemically activated methyl‐d1‐methylsilane‐d2 and ethylsilane‐d3

Chemically activated cis-1,2-dimethylcyclopropane from photolysis of cis-2-butene-diazomethane mixtures in the presence of oxygen

Photochemical Reaction of Diazomethane with Hydrogen-Terminated Silicon Surfaces

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The decomposition kinetics of chemically activated methyl‐d₁‐methylsilane‐d₂ and ethylsilane‐d₃

The decomposition kinetics of chemically activated methyl‐d₁‐methylsilane‐d₂ and ethylsilane‐d₃