Disilyne
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Names | |||
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IUPAC name
Disilyne
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Identifiers | |||
3D model (
JSmol ) |
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ChemSpider | |||
PubChem CID
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Properties | |||
H2Si2 | |||
Molar mass | 58.186 g·mol−1 | ||
Related compounds | |||
Related compounds
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methylacetylene
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Disilyne is a silicon hydride with the formula Si
2H
2. Several isomers are possible, but none are sufficiently stable to be of practical value. Substituted disilynes contain a formal silicon–silicon triple bond and as such are sometimes written R2Si2 (where R is a substituent group). They are the silicon analogues of alkynes.
The term silyne has two diverse meanings. Some chemists use it to refer to compounds containing a silicon–silicon triple bond,[1] by analogy to the carbon–carbon triple bond in alkynes, whereas others use the term to refer to compounds containing a silicon–carbon triple bond[2] by analogy to silene, which often refers to compounds containing silicon–carbon double bonds.[3] The term polysilyne can refer to the layer polymer (SiH)n or substituted derivatives.[1]
Substituted disilynes
The first substituted disilyne to be isolated and characterised by X-ray crystallography is one with an additional trisubstituted silicon group on each silicon of the disilyne core. The structure , where = HC(SiMe3)2 and =
It was prepared by the reduction of the related tetrabrominated precursor by
The geometry of disilynes is unlike that of analogous carbon structures. Whereas substituted alkynes, such as , are linear, having a 180°
Calculations show a bond order of 2.6. An alternative calculation of the bond order by a different group describes the bonding as essentially due to only two electron pairs, with the third pair in a non-bonding orbital.[5][6][7] Reaction of this compound with phenylacetylene produced a 1,2 disilabenzene.[8] Other workers[9] have also reported another related compound which contains a hexasila-3-yne chain:
- R3Si(SiR3)SiMeSi2SiMe(SiR3)SiR3
- where Me = methyl and R = t-butyl
In this compound, the Si–Si triple bond length was calculated as 207 pm.
Heavier group 14 analogues
Triple bonded compounds of the heavier members of
See also
References
- ^ ISBN 0-12-352651-5
- S2CID 97098444.
- ISBN 978-0-08-037941-8.
- S2CID 24416825.
- PMID 16144004.
- PMID 16596606.
- .
- PMID 17542592.
- .
- .
- PMID 12022812.
- PMID 19750717.