Metastable ion study of organosilicon compounds. Part XIII: dimethoxydimethylsilane, (CH3)2Si(OCH3)2, and dimethoxymethylsilane, CH3SiH(OCH3)2

Tajima, Susumu; Sekiguchi, Osamu; Watanabe, Yuko; Nakajima, Satoshi; Takahashi, Yutaka

doi:10.1002/jms.184

Cited by 8 publications

(4 citation statements)

References 14 publications

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“…The release of the silicon-based species, such as CH 3 SiH (m/z = 44), between 300 and 700 • C due to the redistribution reactions between the Si-O bonds and Si-H or Si-C bonds was also in good agreement with the literature [35][36][37].…”

Section: Conversion Process: From the Polymer Precursor To Ceramicsupporting

confidence: 88%

Silicon Carbide Precursor: Structure Analysis and Thermal Behavior from Polymer Cross-Linking to Pyrolyzed Ceramics

et al. 2022

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The Silres H62C methyl-phenyl-vinyl-hydrogen polysiloxane is a promising candidate as a SiC precursor for 3D printing based on photopolymerization reaction. An in-depth nuclear magnetic resonance spectroscopy analysis allowed us to determine its structure and quantify its functional groups. The polysiloxane was found to have a highly branched ladder-like structure, with 21.9, 31.4 and 46.7% of mono-, di- and tri-functional silicon atoms. The polysiloxane cross-links from 180 °C using hydrosilylation between silyl groups (8.4% of the total functional groups) and vinyl groups (12.0%) and contains a non-negligible ethoxy content (2.4%), allowing cross-linking through a hydrolyze/condensation mechanism. After converting the polymer into ceramic and thus releasing mainly hydrogen and methane, the ceramic yield was 72.5%. An X-ray diffraction analysis on the cross-linked and pyrolyzed polysiloxane showed that the ceramic is amorphous at temperatures up to 1200 °C and starts to crystallize from 1200 °C, leading into 3C-SiC carbon-rich ceramic at 1700 °C in an argon atmosphere.

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Section: Conversion Process: From the Polymer Precursor To Ceramicsupporting

confidence: 88%

Silicon Carbide Precursor: Structure Analysis and Thermal Behavior from Polymer Cross-Linking to Pyrolyzed Ceramics

et al. 2022

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“…The formation mechanisms of the ions at m/z 59 and 45 are well known and therefore they are not presented in this paper. 12 In the case of 3 and 3-d 9 , no molecular ion can be detected in their spectra. However, low-abundant [M CH 3 ] C ions formed by the loss of a methyl radical from the silicon atom are observed as in the case of 1 and 2.…”

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confidence: 95%

Mass spectrometric behaviour of (E)‐1‐silyl‐2‐alkoxyethenes

2003

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Mass spectrometric behaviour of (E)-1-silyl-2-alkoxyethenesThe behaviour of ionized organosilicon compounds upon electron impact has been extensively examined. 1 -5 3 ] Cž , has been established to involve primarily elimination of the methyl radical at the silicon atom followed by the loss of acetylene through transfer of a hydrogen atom from theˇ-carbon to the silicon atom (ˇ-transfer). Soderquist and Hassner 6 found that the transfer of R to the silicon (˛-transfer) is an important process in the fragmentation patterns of substituted vinylsilanes, mainly R 0 3 SiC(R) CH 2 (R D D, Br, OMe, OSiMe 3 , Ph). Whereas˛-andˇ-substituted vinylsilanes (R 0 3 Si)(R)C CH 2 and R 0 3 SiCH CHR have become very common silyl reagents used in regio-and stereoselective organic synthesis, 7 there are only a few reports on the substituent effect at silicon and at carbon atoms on the fragmentation mechanism of these class of organometallics. Styrylsilanes, PhCH CHSiR 0 3 , are the only -substituted vinylsilanes whose detailed fragmentation has been resolved. 8 Therefore, the aim of this work was to elucidate the decomposition characteristics of (E)-1-silyl-2-alkoxyethenes (Scheme 1) as the first example of silyl(alkoxy)ethenes containing a functional group (ether) at a carbon atom (R 0 3 SiCH CHOR). These compounds were prepared using the recently developed synthetic method based on cross-disproportionation (silylative coupling) of vinyl-trisubstituted silanes with vinyl alkyl ethers catalysed by ruthenium complexes containing or generating Ru-H and/or Ru-Si bonds. 9 The metastable ion spectrometry and highresolution data were used to complete the fragmentation pathways (Scheme 1).Electron ionization (EI) mass spectra of the (E)-1-silyl-2-alkoxyethenes and their labelled derivatives listed in Table 1 The mass spectra of 1 (M r D 144) and 1-d 9 (M r D 153), revealing the presence of molecular ion peaks, are shown in Fig. 1(a) and 1(b), respectively.The B/E linked scan spectra of 1 Cž and [1-d 9 ] C ions indicate a formation of the ions at m/z 73 and 82 identified as Si(CH 3 ) 3 and Si(CD 3 ) 3 , respectively. The ions at m/z 99 of 1 and 108 of 1-d 9 are formed with the elimination of an ethoxy radical from the molecular ions, although it is a minor process. Further, an abundant ion corresponding to the loss of 15 Da from the molecular ion of 1 is observed at m/z 129. This peak can be assigned to the loss of a methyl radical from the trimethylsilyl group or from the ethyl group of the M Cž ion, since the 129 C ion of 1 corresponds to 135 C in the mass spectrum of 1-d 9 . Therefore, it is evident that the major fragmentation begins with methyl radical loss from the trimethylsilyl group. The B/E linked scan spectrum of the ion 129 C from 1 shows a very intense peak at m/z 103 corresponding to the loss of C 2 H 2 , which is followed by a transfer of the ethoxy group to the silicon. An acetylene elimination has been observed in the mass spectra of the other (E)-1-trimethylsilyl-2-alkoxyethenes, (CH 3 ) 3 SiCH CHOR (R D C 3 H 7 , C 4 ...

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“…No details of the ground state geometry were given, except that a C 2V structure was considered as the ground state conformer. Tajima et al 35 have studied DMDMS by mass-analyzed ion kinetic energy (MIKE) spectrometry. They concluded that the fragmentation pattern for silicon compounds is similar to that of the carbon analogues, thought the mechanism of fragmentation is likely different in the two systems.…”

Section: Introductionmentioning

confidence: 99%

Conformations of Dimethoxydimethylsilane: Matrix Isolation Infrared and ab Initio Studies

Kavitha

Viswanathan

2007

J. Phys. Chem. A

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Conformations of dimethoxydimethylsilane (DMDMS) were studied using matrix isolation infrared spectroscopy, by trapping the silane in argon and nitrogen matrixes. The matrix was deposited using both an effusive and a supersonic jet source. The effusive source was maintained at two different temperatures, viz. 298 and 433 K, during deposition to alter the conformational population of the silane. The experimental results were supported by computations performed at both the HF and B3LYP levels, using 6-31++G** basis set. Vibrational frequency calculations were carried out to assign the experimental features and also to ensure that the computed structures did indeed correspond to minima. A conformer with a G+/-G-/+ structure was found to be the ground state, while G+/-T and G+/-G+/- structures were the next higher energy conformers with energies of 1.32 and 1.48 kcal/mol, respectively. Natural bond orbital analysis was carried out at both HF/6-31++G** and B3LYP/6-31++G** level which indicated that the charge-transfer hyperconjugative interactions largely determine the conformational preferences in this molecule. This interaction appears to be smaller in DMDMS than in the corresponding carbon analogue, dimethoxypropane (DMP).

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Metastable ion study of organosilicon compounds. Part XIII: dimethoxydimethylsilane, (CH₃)₂Si(OCH₃)₂, and dimethoxymethylsilane, CH₃SiH(OCH₃)₂

Cited by 8 publications

References 14 publications

Silicon Carbide Precursor: Structure Analysis and Thermal Behavior from Polymer Cross-Linking to Pyrolyzed Ceramics

Silicon Carbide Precursor: Structure Analysis and Thermal Behavior from Polymer Cross-Linking to Pyrolyzed Ceramics

Mass spectrometric behaviour of (E)‐1‐silyl‐2‐alkoxyethenes

Conformations of Dimethoxydimethylsilane: Matrix Isolation Infrared and ab Initio Studies

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