CO2 is used as starting material for many important chemical syntheses, e.g. for the production of urea, methanol, and several carbonates. One of the less known reaction modes of CO2[1,2] is the insertion into a main group or transition metal nitrogen bonds.[3]Most literature reports focus on aminosilanes of the type Me3SiNHR using the TMS substituent as directing group in organic synthesis.[4] In contrast, we used primary amines as starting materials for the synthesis of di(alkylamino)dimethylsilanes Me2Si(NHR)2. Subsequent bis-insertion of CO2 at room temperature yields the corresponding di(alkylcarbamoyloxy)dimethylsilanes Me2Si(OCONHR)2.[5,6]The latter reaction is exothermic and proceeds with very good yields. The products are novel precursors for the synthesis of polydimethylsiloxanes (PDMS). Annealing at moderate temperatures of >120�C generates substituted urea and different linear or cyclic PDMS, depending on the respective conditions (pressure, solvent, temperature).To gain further insight into the reaction mechanism of the CO2 insertion, we performed DFT calculations with a simple model aminosilane, Me2Si(NHMe)2.[6][1] D. Belli Dell'Amico et al., Chem. Rev. 2003  , 103,3857.[2] K. Kraushaar et al., Adv. Inorg. Chem. 2014  , 66, 117.[3] C. A. Stewart et al., Inorg. Chem. 2010  , 49, 11133.[4] M. J. Fuchter, et al., Chem. Commun. 2008 , 2152.[5] C. Wiltzsch et al., Z. Naturforsch., B: J. Chem. Sci. 2011  , 66, 917.[6] K. Kraushaar et al., Organometallics 2012  , 31, 4779.

CO<sub>2</sub> as an oxygen source for oligo- and polysiloxanes

248th National Meeting (2014)

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CO2 as an oxygen source for oligo- and polysiloxanes

CO₂ as an oxygen source for oligo- and polysiloxanes