Reactivity of di tert-butyldimethoxystannane with carbon dioxide and methanol: X-ray structure of the resulting complex

The direct synthesis of dimethyl carbonate with carbon dioxide as solvent and reagent in the presence of tert-Bu 2Sn(OCH 3) 2 led to a resting tin specie characterised as a trinuclear stannadistannoxane complex. The synthesis of dimethyl carbonate from carbon dioxide and methanol was studied with di tert-butyldimethoxystannane under pressure at temperatures ⩽423 K. The formation of dimethyl carbonate is accompanied by transformation of the stannane into a trinuclear complex, the structure of which has been determined by single-crystal X-ray diffraction technique. The relevance of this specie in the catalytic cycle is demonstrated by conducting recycling runs. A preliminary kinetic study underlines the steric influence of the tert-butyl ancillary ligands in the stabilisation of intermediates, by comparison with the n-butyl homologue.