نتایج جستجو برای: silicon compounds

تعداد نتایج: 305527  

Journal: :Chemical communications 2011
Yong Yang Robert M Rioux

Highly regio- and stereoselective hydrothiolation of a wide range of alkynes with various thiols was demonstrated in the presence of a well-defined Rh complex supported on mesoporous SBA-15 silica. The catalyst was easily recovered and reused several times without significant loss of activity or selectivity.

Journal: :Chemical communications 2013
C David F Königs Maria F Müller Nuria Aiguabella Hendrik F T Klare Martin Oestreich

A base-free, catalytic protocol for the dehydrogenative Si-N coupling of weakly nucleophilic N-H groups of heteroarenes or aryl-substituted amines with equimolar amounts of hydrosilanes is reported. Cooperative Si-H bond activation at a Ru-S bond generates a silicon electrophile that forms a Si-N bond prior to the N-H deprotonation by an intermediate Ru-H complex, only releasing H(2).

2012
Patrice Mélinon

SiC is a compound of silicon and carbon with a chemical formula SiC. Silicon carbide(SiC) as a material is the most promising for applications in which high-temperature, high-power, and high-frequency devices, catalyst support, high irradiation environments are needed. Naturally occurring SiC is found only in poor quantities that explains the considerable effort made in the industrial SiC engin...

Journal: :Chemical & pharmaceutical bulletin 2002
Scott Eric Denmark Ramzi Farah Sweis

This review highlights the rapid evolution of the newly-developed class of palladium-catalyzed cross-coupling reactions of organosilicon compounds. A myriad of heteroatom-containing silicon moieties (silyl hydrides, siletanes, silanols, silyl ethers, orthosiliconates, di- and polysiloxanes and pyridylsilanes) undergo mild and stereospecific cross-coupling. The diversity of methods for introduct...

Journal: :Metal-Based Drugs 2002
Edmunds Lukevics Edgars Abele Pavel Arsenyan Ramona Abele Kira Rubina Irina Shestakova Ilona Domracheva Violetta Vologdina

Silicon containing pyridine and quinoline sulfides have been prepared using phase transfer catalytic system thiol/alkyl halide / solid KOH/18-crown-6 / toluene. The target S-ethers were isolated in yields up to 81%. The cytotoxicity of the synthesized compounds was studied. Among pyridine sulfides S-[3-(1-methyl- 1-silacyclohexyl)propyl] derivatives 5e and 6e exhibit the highest cytotoxicity. A...

Journal: :Chemical communications 2012
Kinga Leszczyńska Kai Abersfelder Moumita Majumdar Beate Neumann Hans-Georg Stammler Henry S Rzepa Peter Jutzi David Scheschkewitz

The Cp*Si(+) cation acts as a stoichiometric source of silicon in the reaction with the disilenide Tip(2)Si=Si(Tip)Li (Tip = 2,4,6-(i)Pr(3)C(6)H(2)) affording known neutral unsaturated silicon clusters. It thereby provides a conceptually different approach to this novel class of compounds. The proposed mechanism involves a Cp*-substituted cyclotrisilene in which Cp*(-) acts as a leaving group u...

1999
M. T. SWIHART S. NIJHAWAN M. R. MAHAJAN S.-M. SUH S. L. GIRSHICK

Product contamination by gas-phase nucleation within the processing environment often limits the deposition rate that can be obtained during chemical vapor deposition (CVD) of materials for microelectronics applications. A fundamental understanding of how these particles nucleate and grow may allow us to enlarge the process envelope, providing higher growth rates without particle contamination....

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد شاهرود - دانشکده علوم پایه 1392

اسانس گیاهان (خشک شده در سایه)، tanacetum tenuisectum , tanacetum polycephalum به دو روش: 1- تقطیر با آب 2- برای اولین بار به روش میکرواستخراج فاز جامد در فضای فوقانی گرفته شد و به روش gc/ms مورد آنالیز و شناسایی واقع گردید. عمده ترکیبات اسانس سرشاخه های گلدار گیاه (tanacetum polycephalum) hydrodistillation % compounds 12.07 camphor 10.66 1, 8- cineole 9.57 chrysanthenyl acetate – t...

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