Abstract
Octamethylcyclo-di(meta-silphenylenesiloxane) 1 (cyclic meta-dimer) was synthesized from 1,3-bis(dimethylhydroxysilyl)benzene 7 in a dilute THF solution, in the presence of a catalytic amount of 4-dimethylaminopyridine (DMAP). In contrast, only small amounts of the cyclic meta-dimer 1, cyclic meta-trimer 2, cyclic meta-tetramer, etc. were obtained when the condensation reaction was carried out with the catalyst n-hexylamine 2-ethylhexoate or sodium hydroxide. The major product in these reactions is polymer 8. The structure of compound 1 was confirmed by X-ray crystallography. This cyclic molecule is most likely unstrained since the X-ray structure reveals that the Si–O–Si bond angle is 142.1(1)° which is similar to that in most unstrained siloxane compounds.
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Zhang, R., Pinhas, A.R., Mark, J.E. et al. Synthesis and Structure of Octamethylcyclo-di(meta-silphenylenesiloxane). Journal of Inorganic and Organometallic Polymers 9, 63–77 (1999). https://doi.org/10.1023/A:1021483115907
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DOI: https://doi.org/10.1023/A:1021483115907