Di-n-butyltin oxide as a chemical carbon dioxide capturer

Several synthetic routes to the decakis(di-n-butyltin(IV)) oxocluster, (n-Bu2SnO)6[(n-Bu2SnOCH3)2(CO3)]2 (1), a diorganotin compound previously shown to belong to the class of organotins able to store carbon dioxide, as well as its reactivity toward dimethyl carbonate (DMC), are described. The synthetic route from n-Bu2SnO and DMC was applied for the preparation of the ethoxy analogue of 1, oxocluster 2, using diethyl carbonate. The structural relationship connecting cluster 1, with its precursor PRE-1 isolated from recycling experiments and n-Bu2SnO is discussed. For this purpose, the reactivity of PRE-1 with trifluoromethanesulfonic acid was investigated in order to trace structural data. Solution and solid-state 1D NMR investigations of 1 and 2, as well as 1H–119Sn 2D heteronuclear correlation spectroscopy experiments in solution, shed further insight into structural data.

Graphical abstractThe synthesis of the decakis(di-n-butyltin(IV)) oxocluster, (R2SnO)6[(R2SnOR′)2(CO3)]2 (R = C4H9, R′ = CH3), as well as its reactivity toward organic carbonates and its formation mechanism from R2SnO under supercritical CO2 conditions are explored and supported by IR, NMR (solution and solid-state), and X-ray investigations.Figure optionsDownload full-size imageDownload as PowerPoint slide