Synthesis of siloxanes

Oxygen-17 NMR spectroscopy: Basic principles and applications (Part I)

“…The values of the increments I R for various groups, which are listed in Table 61, were calculated by the shifts of the symmetrically substituted siloxanes and those for trimethylsiloxy-substituted compounds [422]. In the first case the increment is one half of the shift value and in the second it is the difference between the shift observed and the increment of the trimethylsilyl group.…”

“…Several siloxanes and silicates have been investigated (Table 60). d( 17 O) of siloxanes of the form R-O-R 0 occur in the range of 30-90 ppm [422] and can be predicted from the incremental relationship given by:…”

Characterization of siloxane copolymers by solution 17O NMR spectroscopy

“…Derived from the chemical shift data an increment system was established by Scheim et al [4]. This system was extended by several units of siloxane copolymers, see Table 3.…”

“…Signal assignment was performed according to reference values [4], with homopolymers, where only one signal was expected (PDMS-1M, OV-1, Silar 10C, OV-210), and with reference compounds containing analogue functional groups (PEGs, diphenyl ether, polyphenyl ether).…”

“…In a pioneering paper Scheim et al applied solution 17 O NMR spectroscopy for the measurement of siloxanes [4]. The authors reported several chemical shifts of siloxanes with the structure R 3 Si-O-SiR 3 .…”