It should be noted that the silicon - oxygen bonds are much shorter and stronger (809 versus 538 kJ/mol) than the carbon - oxygen bonds. The polarity of this bond increases towards oxygen. Examples of this are silyl acetals RR'Si(OR)2, silanols"), siloxanes and the polymer polysiloxane"). Silyl ethers") are used as protecting groups for alcohols. Only silicon-fluorine bonds are stronger than carbon-fluorine bonds and that is why the fluorine source TASF") (or, more commonly TBAF")) are useful in deprotection. The favorable formation of Si-O bonds leads to many organic reactions such as the Brook rearrangement") and Peterson olefination").

Another manifestation is the highly explosive nature of the silicon pendant groups, Si(CHONO) and Si(CHN), of pentaerythritol tetranitrate*:[13]​[14]​*.

A single crystal of this compound, first synthesized in 2007, detonates even when in contact with a Teflon spatula and, in fact, its complete characterization was impossible. Another factor contributing to its exothermic decomposition (deduced from much safer in silico experimentation) is the ability of silicon in its crystal phase to coordinate with two nitrite oxygen groups, in addition to its regular coordination with the four carbon atoms. This additional coordination would make it easier to form silicon dioxide (one of the decomposition products).

Organosylyl halides are important reagents in organic chemistry, particularly the trimethylsilyl chloride MeSiCl. A classic method called Flood reaction for the synthesis of this type of compounds is by heating RSiOSiR hexaalkyldisiloxanes with concentrated sulfuric acid and a sodium halide.[15] Other relevant silyl halides are: dichloromethylphenylsilane, dimethyldichlorosilane"), methyltrichlorosilane, (4-aminobutyl)diethoxymethylsilane, trichloro(chloromethyl)silane, trichloro(dichlorophenyl)silane, trichloroethylsilane, trichlorophenylsilane and trimethylchlorosilane.

Contenido

El enlace silicio - hidrógeno es más largo que el enlace C-H (148 frente a 105 pm de longitud de enlace) y es más débil (299 frente a 338 kJ/mol de energía de enlace). El hidrógeno es más electronegativo que el silicio y de ahí la convención de nomenclatura de hidruro de sililo (al igual que el grupo metilo que deriva del metano). El compuesto de origen SiH se llama silano, y uno de sus derivados es el fenilsilano"). Los hidruros de sililo son muy reactivos y se utilizan como agentes reductoress, por ejemplo, PMHS").

En un estudio el trietilsililo se utilizó en la conversión de un fenilazida en un anilina:[16]​.

En esta reacción el ACCN&action=edit&redlink=1 "1,1'-azobis(ciclohexano-1-carbonitrilo) (aún no redactado)") es un iniciador de radicales") y un tiol alifático transfiere el carácter radical al hidruro de sililo. El radical libre trietilsililo reacciona luego con la azida con expulsión de nitrógeno a un radical N-sililarilaminilo que abstrae un protón de un tiol para completar así el ciclo catalítico:.

El tratamiento final con agua produce la anilina.

Los hidruros de sililo pueden incluso producir hasta la reducción de moléculas muy estables como dióxido de carbono (para dar metano):[17]​.

Aunque ello necesita un sistema catalizador muy complejo.

Hydrosilylation

Silyl hydrides react with different unsaturated substrates such as alkenes, alkynes, imines, carbonyls and oximes giving new organic silicon compounds in a process called hydrosilylation. In the reaction of triphenylsilyl hydride with phenylacetylene the reaction product is a trans or cis isomer, or the geminal vinylsilane, for example:[18]​ trans.

In the related silyl metallation, a metal replaces the hydrogen atom.

Organic silicon compounds, unlike their carbon counterparts, do not possess rich double bond chemistry due to the large difference in electronegativity. Flowers provided the first evidence for the existence of silenes from the pyrolysis of dimethylsilacyclobutane.[20]​ The first stable (kinetically armored) silene was discovered in 1981 by Brook.[21]​.

Disilenes") have a Si=Si double bond and disilinos") are analogues of an alkyne with silicon. The first silino (with a triple bond between silicon and carbon, Si≡C) was reported in 2010.

silols, also called silacyclopentadienes, are members of a broader class of compounds called metalols",[22]​ are the silicon analogues of pyrroles and are of current academic interest due to their electroluminescence and other electronic properties.[23][24]​ Silols are efficient in electron transport. They owe their low LUMO to a favorable interaction between the sigma orbital antibonding of silicon with an antibonding pi orbital of the butadiene fragment.

Unlike carbon, silicon compounds can present coordination with five atoms, as occurs in a group of compounds ranging from the so-called silatranes, for example, phenylsilatrane), to a single stable pentaorganosilicate: [25]​.

Los compuestos organosilícicos se encuentran ampliamente en productos comerciales. Los más comunes son los antiespumantes, masillas (selladores), adhesivos y revestimientos hechos de siliconas. Otros usos importantes son los adyuvantes agrícolas y de control de plantas que se suelen utilizar junto con herbicidas y fungicidas.[26]​.

.

biology and medicine

Carbon-silicon bonds are absent in biology, however enzymes have been used to artificially create carbon-silicon bonds in living microbes.[27][28][29] Silicates, on the other hand, have a known existence in diatoms.[3] Silafluofen") is an organosilicon compound that functions as an insecticidal pyrethroid. Several organosilicon compounds have been investigated as products pharmaceuticals.[30][31]​.

It should be noted that the silicon - oxygen bonds are much shorter and stronger (809 versus 538 kJ/mol) than the carbon - oxygen bonds. The polarity of this bond increases towards oxygen. Examples of this are silyl acetals RR'Si(OR)2, silanols"), siloxanes and the polymer polysiloxane"). Silyl ethers") are used as protecting groups for alcohols. Only silicon-fluorine bonds are stronger than carbon-fluorine bonds and that is why the fluorine source TASF") (or, more commonly TBAF")) are useful in deprotection. The favorable formation of Si-O bonds leads to many organic reactions such as the Brook rearrangement") and Peterson olefination").

Another manifestation is the highly explosive nature of the silicon pendant groups, Si(CHONO) and Si(CHN), of pentaerythritol tetranitrate*:[13]​[14]​*.

A single crystal of this compound, first synthesized in 2007, detonates even when in contact with a Teflon spatula and, in fact, its complete characterization was impossible. Another factor contributing to its exothermic decomposition (deduced from much safer in silico experimentation) is the ability of silicon in its crystal phase to coordinate with two nitrite oxygen groups, in addition to its regular coordination with the four carbon atoms. This additional coordination would make it easier to form silicon dioxide (one of the decomposition products).

Organosylyl halides are important reagents in organic chemistry, particularly the trimethylsilyl chloride MeSiCl. A classic method called Flood reaction for the synthesis of this type of compounds is by heating RSiOSiR hexaalkyldisiloxanes with concentrated sulfuric acid and a sodium halide.[15] Other relevant silyl halides are: dichloromethylphenylsilane, dimethyldichlorosilane"), methyltrichlorosilane, (4-aminobutyl)diethoxymethylsilane, trichloro(chloromethyl)silane, trichloro(dichlorophenyl)silane, trichloroethylsilane, trichlorophenylsilane and trimethylchlorosilane.

Contenido

El enlace silicio - hidrógeno es más largo que el enlace C-H (148 frente a 105 pm de longitud de enlace) y es más débil (299 frente a 338 kJ/mol de energía de enlace). El hidrógeno es más electronegativo que el silicio y de ahí la convención de nomenclatura de hidruro de sililo (al igual que el grupo metilo que deriva del metano). El compuesto de origen SiH se llama silano, y uno de sus derivados es el fenilsilano"). Los hidruros de sililo son muy reactivos y se utilizan como agentes reductoress, por ejemplo, PMHS").

En un estudio el trietilsililo se utilizó en la conversión de un fenilazida en un anilina:[16]​.

En esta reacción el ACCN&action=edit&redlink=1 "1,1'-azobis(ciclohexano-1-carbonitrilo) (aún no redactado)") es un iniciador de radicales") y un tiol alifático transfiere el carácter radical al hidruro de sililo. El radical libre trietilsililo reacciona luego con la azida con expulsión de nitrógeno a un radical N-sililarilaminilo que abstrae un protón de un tiol para completar así el ciclo catalítico:.

El tratamiento final con agua produce la anilina.

Los hidruros de sililo pueden incluso producir hasta la reducción de moléculas muy estables como dióxido de carbono (para dar metano):[17]​.

Aunque ello necesita un sistema catalizador muy complejo.

Hydrosilylation

Silyl hydrides react with different unsaturated substrates such as alkenes, alkynes, imines, carbonyls and oximes giving new organic silicon compounds in a process called hydrosilylation. In the reaction of triphenylsilyl hydride with phenylacetylene the reaction product is a trans or cis isomer, or the geminal vinylsilane, for example:[18]​ trans.

In the related silyl metallation, a metal replaces the hydrogen atom.

Organic silicon compounds, unlike their carbon counterparts, do not possess rich double bond chemistry due to the large difference in electronegativity. Flowers provided the first evidence for the existence of silenes from the pyrolysis of dimethylsilacyclobutane.[20]​ The first stable (kinetically armored) silene was discovered in 1981 by Brook.[21]​.

Disilenes") have a Si=Si double bond and disilinos") are analogues of an alkyne with silicon. The first silino (with a triple bond between silicon and carbon, Si≡C) was reported in 2010.

silols, also called silacyclopentadienes, are members of a broader class of compounds called metalols",[22]​ are the silicon analogues of pyrroles and are of current academic interest due to their electroluminescence and other electronic properties.[23][24]​ Silols are efficient in electron transport. They owe their low LUMO to a favorable interaction between the sigma orbital antibonding of silicon with an antibonding pi orbital of the butadiene fragment.

Unlike carbon, silicon compounds can present coordination with five atoms, as occurs in a group of compounds ranging from the so-called silatranes, for example, phenylsilatrane), to a single stable pentaorganosilicate: [25]​.

Los compuestos organosilícicos se encuentran ampliamente en productos comerciales. Los más comunes son los antiespumantes, masillas (selladores), adhesivos y revestimientos hechos de siliconas. Otros usos importantes son los adyuvantes agrícolas y de control de plantas que se suelen utilizar junto con herbicidas y fungicidas.[26]​.

.

biology and medicine

Carbon-silicon bonds are absent in biology, however enzymes have been used to artificially create carbon-silicon bonds in living microbes.[27][28][29] Silicates, on the other hand, have a known existence in diatoms.[3] Silafluofen") is an organosilicon compound that functions as an insecticidal pyrethroid. Several organosilicon compounds have been investigated as products pharmaceuticals.[30][31]​.