0000000000874599
AUTHOR
Gábor Laurenczy
High-pressure NMR spectroscopy: An in situ tool to study tin-catalyzed synthesis of organic carbonates from carbon dioxide and alcohols. Part 2 [1]
Dialkoxide diorganotin(IV) complexes are known to readily react with carbon dioxide under pressure and they are considered as suitable catalyst precursor models for the direct synthesis of organic carbonates. To gain a better understanding of CO2 insertion processes with Sn-OR bonds, the reactivity of n-Bu2Sn(OCH(CH3)(2))(2) (2) was investigated using high-pressure NMR (HP-NMR) spectroscopy. In deuterated solvents (isopropanol-d(8) and toluene-d(8)) under 50 bar of CO2 pressure at 80 degrees C, Sn-119{H-1} NMR experiments revealed the exclusive formation of an unprecedented tetraorganodistannoxane species, characterized as the bis[diisopropycarbonatotetrabutyldistannoxane] complex, {[n-Bu2S…
Di-n-butyltin(IV)-catalyzed dimethyl carbonate synthesis from carbon dioxide and methanol: An in situ high pressure 119Sn{1H} NMR spectroscopic study
The reactivity of five di-n-butyltin(IV) complexes, n-Bu2Sn(OR)(2) (1), n-Bu2SnO (3), [n-Bu2Sn(OR)](2)O (4), (n-Bu2SnO)(2)(CO2) (6) and (n-Bu2SnO)(6)[(n-Bu2SnOR)(2)(CO3)](2) (7) (R = CH3), with CO2, suggested as possible catalyst precursors and key-intermediates for the direct synthesis of dimethyl carbonate from carbon dioxide and methanol, has been investigated using high-pressure Sn-119{H-1} NMR (HP-NMR) spectroscopy. Four of the five precursors studied, i.e. 3, 4, 6 and 7 give rise to an identical Sn-119{H-1} NMR pattern which can be explicitly attributed to the fingerprint of the dimeric form of the 1-methoxy-3-methylcarbonatotetrabutyldistannoxane {5}(2). However, with 1, a new pair o…