scholarly journals Squalene interactions with some hydrosilanes and hydrogermans

2020 ◽  
Vol 64 (11) ◽  
pp. 42-54
Author(s):  
Dmitry A. Efimenko ◽  
◽  
Irina B. Sokolskaya ◽  
Mihail M. Sibircev ◽  
Valentin G. Lahtin ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Silicon Germanium ◽  
Spectral Study ◽  
Electrophilic Addition ◽  
Addition Reactions ◽  
Hydrogen Atoms ◽  
Chlorine Atoms ◽  
Effect Of Substituents ◽  
Alkoxy Groups

Squalene hydrosilylation by a number of organohydrosilanes R3SiH and Me3GeH, including a mixture of α- and β-isomers of adducts of vinyltrimethylsilane addition to tetramethyldisiloxane: HSi(Me2)O(Me2)Si-C(Me)-SiMe3 and HSi(Me2)O(Me2)Si-(CH2)2-SiMe3, formed both according to Markovnikov's rule and against it, is discussed. We pay attention to the mismatch of values between the electronegativities of carbon, silicon, germanium and hydrogen atoms and the reactivity of C-H, Si-H, and Ge-H bonds. A spectral study of a mixture of α- and β-isomers was carried out. The effect of substituents at elements on its reactivity is discussed: hydrosilanes with chlorine atoms, alkyl and alkoxy groups on silicon are not active in the squalene hydrosilylation. In contrast to them, the α- and β-adducts and their mixture add well to squalene with an unambiguously unknown regioselectivity. The results obtained indicate the special behavior of squalene in electrophilic addition reactions catalyzed by metal complexes, in contrast to substituted ethylenes.

The effects controlling the oxygen basicity in alkoxysilanes (RO)nSi(CH3)4-n. The mutual polarizability effect of alkoxy groups attached to silicon

1979 ◽  
Vol 44 (3) ◽  
pp. 750-755 ◽  
Author(s):  
Josef Pola ◽  
Marie Jakoubková ◽  
Václav Chvalovský
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Electronic Effect ◽  
Linear Regression Analysis ◽  
Effect Of Substituents ◽  
Relative Basicity ◽  
Polarizability Effect ◽  
Alkoxy Groups ◽  
Individual Series

Relative basicity of the oxygen in alkoxysilanes (RO)nSi(CH3)3-n having n = 1-4 and various electrondonating and electronwithdrawing groups R measured as Δν(OH) of phenol due to its interaction with these compounds in CCl4 is shown to be chiefly controlled by the electronic effect of substituents R. Linear regression analysis of the Δν(OH) vs n relatioship for individual series (RO)nSi(CH3)4-n suggests the operation of the polarizability effect of RO groups becoming more important with increasing electronwithdrawing nature of R.

Übergangsmetallkomplexe mit Schwefelliganden, LXXVI Redox- und Additionsreaktionen von Nickelkomplexen mehrzähniger Thioether-Thiolat-Liganden. Röntgenstrukturanalysen von (NMe4)2[Ni(′S2′)2] und [Ni(′S4 – C3′)(PMe3)] / Transition Metal Complexes with Sulfur Ligands, LXXVI Redox and Addition Reactions of Nickel Complexes with Multidentate Thioether-Thiolato Ligands. X-Ray Structure Determinations of (NMe4)2[Ni(′S2′)2] and [Ni(′S4–C3′)(PMe3)]

1991 ◽  
Vol 46 (12) ◽  
pp. 1601-1608 ◽  
Author(s):  
Dieter Sellmann ◽  
Stefan Fünfgelder ◽  
Falk Knoch ◽  
Matthias Moll
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Structure Analysis ◽  
Transition Metal Complexes ◽  
Nickel Complexes ◽  
Addition Reactions ◽  
Coordination Geometry ◽  
X Ray ◽  
Square Planar ◽  
Structure Determinations

In order to elucidate specific properties of nickel sulfur complexes, redox and addition-elimination reactions of [Ni(′OS4')]2, [Ni(′NHS4')]2, [Ni(′S5')], [Ni('S4—C5')], and [Ni('S4—C3')] were investigated ('OS4′ 2' = 2,2'-bis(2-mercaptophenylthio)diethylether(2—), 'NHS4'2- = 2,2'-bis(2-mercaptophenylthio)diethylamine(2—), 'S5'2- = 2,2'-bis(2-mercaptophenylthio)diethylsulfide(2—), 'S4-C5'2- = 1,5-bis(2-mercaptophenylthio)pentane(2—), 'S4—C3'2- = 1,3-bis(2-mercaptophenylthio)propane(2—)).Cyclovoltammetry proves the complexes to be redox inactive between —1.4 and +0.8 V vs. NHE. Above +0.8 V the complexes are irreversibly oxidized, below —1,4 V desalkylation takes place and [Ni(′S,′)2]2- is formed. An X-ray structure analysis was carried out of (NMe4)2[Ni(′S2')2], which shows a planar anion with the Ni center in a nearly perfect square planar coordination. Distances and angles are practically identical to those in the [Ni(′S2')2-] monoanion.The complexes coordinate only phosphines as coligands, but thioether donors simultaneously decoordinate and, dependant of reaction temperature, mono- or trisphosphine complexes are formed. [Ni(′S4—C3')(PMe3)] was characterized by X-ray structure analysis and exhibits a square pyramidal coordination geometry.

ELECTROPHILIC ADDITION REACTIONS OF FLUORO-OLEFINS

1966 ◽  
Vol 35 (6) ◽  
pp. 417-427 ◽  
Author(s):  
B L Dyatkin ◽  
E P Mochalina ◽  
Ivan L Knunyants
Keyword(s):  
Electrophilic Addition ◽  
Addition Reactions

AN INVESTIGATION OF THE CHLORINATION OF SPRUCE WOOD AND OF THE RESULTING CHLOROLIGNIN

1937 ◽  
Vol 15b (7) ◽  
pp. 279-294 ◽  
Author(s):  
G. V. Jansen ◽  
J. W. Bain
Keyword(s):  
Methyl Alcohol ◽  
Ring Structure ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Hydrogen Atoms ◽  
Chlorine Atoms ◽  
Spruce Wood ◽  
Simple Substitution ◽  
Homogeneous Fraction ◽  
Acid Reduction

Spruce sawdust was chlorinated under various conditions in an attempt to procure a homogeneous lignin chloride. Success finally attended the use of methyl alcohol as a medium for chlorination. The lignin chloride, which was dissolved by the alcohol during the chlorination and subsequently precipitated by the addition of water, was cream white in color, and analysis showed it to be an alcohol lignin.A homogeneous fraction (No. 2) was obtained from the re-chlorinated product, and it proved to be a chlorinated analogue of Hibbert's monomethylated methyl alcohol lignin, the formulas of the two products being C42H22O6Cl13(OH)2(OCH3)7, and C42H32O6(OH)3(OCH3)7. The molecular weight and the presence of the two hydroxyl groups were confirmed by acetylation, when 2.0 acetyl groups entered the molecule. Eleven of the chlorine atoms in Fraction 2 have evidently replaced ten hydrogen atoms and one hydroxyl group by simple substitution in methyl alcohol lignin, leaving two chlorine atoms which have apparently entered to saturate a double bond. Seven of these chlorine atoms have been shown to be readily removable either by an alkali or by acid reduction. The other six, because of their stable union with the molecule, are surmised to be joined to an aromatic nucleus or at least to some type of ring structure. The product has been shown to react stoichiometrically within limits as narrow as could be expected for such a large molecule.

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