Characterization of stationary phases for gas chromatography by 29Si nuclear magnetic resonance spectroscopy III. Carborane-siloxane copolymers.
Five bis(dimethylsilyl)-m-carborane-siloxane polymers with methyl, phenyl, and 2-cyanoethyl ligands were characterized by (1)H, (11)B, (13)C, and (29)Si nuclear magnetic resonance (NMR) spectroscopy. All relevant chemical shifts are reported, whereas signal assignment was confirmed by 2D NMR spectroscopy. The chemical composition of the polymers was calculated from the (1)H and (29)Si NMR spectra. Only (29)Si NMR spectroscopy was able to quantify the methoxy end group, from which the average molecular weights were calculated. The copolymer Dexsil 300 turned out to have a regular microstructure, whilst the terpolymers Dexsil 400 and Dexsil 410 have only partly regular sequences. (11)B NMR spectroscopy confirmed the m-carborane structure and revealed some low molecular weight impurities.
Kählig
Hanspeter
H
Institute of Organic Chemistry, Vienna University, Währinger Strasse 38, A-1090 Vienna, Austria. hanspeter.kaehlig@univie.ac.at
Mayer-Helm
Bernhard X
BX
D001880:Boranes / Q000737:chemistry*; D002849:Chromatography, Gas / Q000379:methods*; D007554:Isotopes; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*; D012825:Silicon; D012833:Siloxanes / Q000737:chemistry*
D001880:Boranes; D007554:Isotopes; D011108:Polymers; D012833:Siloxanes; D012825:Silicon