Journal article
Selective Formation of Functionalized Disiloxanes from Terphenylfluorosilanes.



Publication Details
Authors:
Pietschnig, R.; Merz, K.
Publisher:
American Chemical SocietyDO - 10.1021/om034193l
Publication year:
2004
Journal:
Organometallics
Pages range:
1373-1377
Volume number:
23
Start page:
1373
End page:
1377
ISSN:
0276-7333

Abstract
The reactivity of the sterically hindered organofluorosilane 2,6-Mes2C6H3SiF3 (1) (Mes = 2,4,6-trimethylphenyl) under hydrolytic conditions differs substantially from that of the corresponding organo chlorosilane. During the hydrolysis of 1 the combination of thermodn. (increased Si-F bond strengths compared to Si-Cl) and kinetic aspects (steric hindrance) favors condensation of intermediately formed silanol over the hydrolysis to give a silanetriol. In the course of the reaction no evidence for a silanetriol could be found, while the corresponding difluorosilanol seems to be a key intermediate. The condensation of this difluorosilanol leads to a tetrafluorodisiloxane, (2,6-Mes2C6H3SiF2)2O (2), which can be isolated. Further displacement of the remaining fluorine atoms in this siloxane is possible with organolithium reagents or base. In the former case, reaction of 2 with MeLi yielded (2,6-Mes2C6H3SiMe2)2O, which was characterized by x-ray crystallog. In the latter case the deprotonated disiloxanetetrol is formed, which due to its fourfold silanol functionality is a suitable precursor for metallasiloxanes. The deprotonated disiloxanetetrol forms a dimeric structure in the solid state, [K+-OSi(OH)(2,6-Mes2C6H3)SiOSi(OH)2(2,6-Mes2C6H3)]2, which is stabilized by hydrogen bonding and potassium aryl interactions. [on SciFinder(R)]


Keywords
crystal structure potassium disiloxanetetrol dimer bisterphenyltetramethyldisiloxane, disiloxane bisterphenyl tetramethyl prepn structure, fluorosilane terphenyl silicon fluorine bond hydrolysis steric hindrance condensation, fluoro terphenyl disiloxane prepn reaction methyllithium, mol structure potassium disiloxanetetrol dimer bisterphenyltetramethyldisiloxane, potassium disiloxane tetrol dimer prepn structure hydrogen bond


Authors/Editors

Last updated on 2019-25-07 at 16:02