Synthesis of high-purity alkylsilanes

Сидоров, Д. В.; Стороженко, П. А.; Shutova, O. G.; Kozhevnikov, B. E.

doi:10.1134/s0040579507050363

Cited by 3 publications

(1 citation statement)

References 2 publications

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“…The Si–C bond, with a substantial bond energy of ∼377 kJ/mol, is ubiquitous in organic reaction synthesis, in natural product synthesis, and in the preservation of the stereochemistry in complex organic molecules . Due to their stability, alkylsilanes are used in a variety of industries including the electrical, electronics, and aeronautical industries and are also promising surfactants in the production of the nanostructured surfaces needed for making complex macroassemblies . Early in the development of the chemistry of methylsilicon phthalocyanines, however, it was observed that while the Si–C bond in these compounds is stable to heat, it is readily photolyzed by near-infrared light in solution, which was utilized synthetically by Kenney and co-workers for developing the photodynamic therapy (PDT) candidate Pc 4, a silicon phthalocyanine bearing two axial ligands consisting of a hydroxyl group and a silylalkyl amine .…”

Section: Introductionmentioning

confidence: 99%

NIR Photocleavage of the Si–C Bond in Axial Si-Phthalocyanines

et al. 2014

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The use of light-triggered photolysis provides a powerful tool for unique syntheses and for applications that require remote operation such as drug delivery or molecular switches. Here, we describe the photochemistry of a recently developed alkylsilicon phthalocyanine Pc 227, which undergoes an exchange of the alkyl ligand for a ligand derived from the solvent when the axial Si-C bond is photolyzed in a solvent with low-energy visible light. In this work with methanol as the solvent, we investigate the formation of the methoxy analogue of the therapeutic drug Pc 4, (termed Pc 233) upon irradiation. Using steady-state spectroscopy and characterization of the photoproducts, the competing pathways between direct ligand exchange on the central silicon atom and delocalization of the radical produced by homolysis on the phthalocyanine ring is observed. The delocalized radical intermediate is quite long-lived. At long times this intermediate decomposes without significant formation of Pc 233. The results of this investigation provide insights into recent work utilizing Pc 227 for drug delivery applications and for future work on the use of phthalocyanines as long-wavelength phototriggers.

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Section: Introductionmentioning

confidence: 99%

NIR Photocleavage of the Si–C Bond in Axial Si-Phthalocyanines

et al. 2014

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4.4.4.8 Silyl Hydrides (Update 2015)

Oestreich¹,

Ramsden²,

Wirth³

2015

Knowledge Updates 2015/1

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Hydrogen elimination from the dissociation of methyl-substituted silanes on tungsten and tantalum surfaces

Toukabri

Shi

2016

Can. J. Chem.

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The elimination of H2 from the dissociation of four methyl-substituted silane molecules, including monomethylsilane (MMS), dimethylsilane (DMS), trimethylsilane (TriMS), and tetramethylsilane (TMS), on a heated tungsten or tantalum filament surface has been studied using laser ionization mass spectrometry. Two complementary ionization methods, i.e., single photon ionization (SPI) using a vacuum ultraviolet wavelength at 118 nm (10.5 eV) and a dual ionization source incorporating both 10.5 eV SPI and laser-induced electron ionization, were employed to detect the production of H2. Examination of the intensity of the H2+ peak from the four molecules has shown that it increases with temperature until reaching a plateau at around 2000−2100 °C on both tungsten and tantalum filaments. These methyl-substituted silanes are dissociatively adsorbed on tungsten and tantalum surfaces by Si−H bond cleavage, and as the temperature is raised, by C−H bond rupture. Experiments with the isotopomers of MMS, DMS, and TriMS have shown that the formation of H2 follows the Langmuir−Hinshelwood mechanism where two adsorbed hydrogen atoms on metal surfaces recombine to produce H2. The determined activation energy (Ea) for H2 formation from MMS, DMS, and TriMS, in the range of 58.2−93.4 kJ mol−1, has been found to increase with the number of methyl substitutions in the precursor molecule. Comparison of these Ea values with the reported values of 51.1−78.8 kJ mol−1 for the methyl radical formation from the same three precursor molecules has led to the conclusion that the initial Si−H bond cleavage in the dissociative adsorption of MMS, DMS, and TriMS is the rate-limiting step for the formation of both H2 molecules and ·CH3 radicals.

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Synthesis of high-purity alkylsilanes

Cited by 3 publications

References 2 publications

NIR Photocleavage of the Si–C Bond in Axial Si-Phthalocyanines

NIR Photocleavage of the Si–C Bond in Axial Si-Phthalocyanines

4.4.4.8 Silyl Hydrides (Update 2015)

Hydrogen elimination from the dissociation of methyl-substituted silanes on tungsten and tantalum surfaces

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