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Monosubstituted octasilasesquioxanes
Author(s) -
Marcolli Claudia,
Calzaferri Gion
Publication year - 1999
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/(sici)1099-0739(199904)13:4<213::aid-aoc841>3.0.co;2-g
Subject(s) - chemistry , microporous material , siloxane , silanes , molecule , ring (chemistry) , raman spectroscopy , hydrolysis , mass spectrometry , nuclear magnetic resonance spectroscopy , infrared spectroscopy , computational chemistry , polymer chemistry , organic chemistry , silane , physics , chromatography , optics , polymer
Octasilasesquioxanes are cube‐shaped molecules consisting of a Si 8 O 12 core and eight reactive sites, which can, in principle, all be functionalized differently. This review article provides an overview of the work, which is concerned with the monosubstituted species, R′R 7 Si 8 O 12 , where R′ and R are two different substituents, such as organic or organometallic groups or single atoms (H, Cl). Three synthetic routes have been used so far to prepare monosubstituted silasesquioxanes: co‐hydrolysis of trifunctional organo‐ or hydro‐silanes, substitution reactions with retention of the siloxane cage, and corner‐capping reactions. These three different strategies are discussed in this review. Various spectroscopic techniques that have been applied to characterize these molecules — X‐ray diffraction, NMR, IR and Raman spectroscopy as well as mass spectrometry — are treated. A main focus is the notion of ring‐opening vibration, which is supposed to be generally applicable to microporous materials, especially zeolites. A simple model for explaining the nature of ring‐opening vibrations is presented. Based on the new possibilities offered by functionalized silasesquioxanes, challenging perspectives for the synthesis of novel materials are discussed. Copyright © 1999 John Wiley & Sons, Ltd.