Difunctional distannoxanes, XR2SnOSnR2X

Formation of Dimethyl Carbonate from CO2 and Methanol Catalyzed by Me2SnO: A Density Functional Theory Approach

The conversion of CO₂ into dimethyl carbonate (DMC) is an environmental and industrial appealing topic because it contributes to reduce the emissions of CO₂ and to increase its use as raw material. In the present study we employed the CAM-B3LYP/def2-SVP DFT approach to evaluate the thermodynamic and kinetic parameters for the catalytic conversion of CO₂ and methanol into DMC. Starting with the activation of four methanol molecules by the [Me₂SnO]₂ dimer, we computed all the stationary points along the pathway to convert CO₂ and methanol into the DMC. The capture of two CO₂ molecules is promoted by an alkoxitin intermediate, in an exothermic process, with low activation energy. Formation of a first DMC occurs after an intramolecular rerrangement involving a tetrahedral intermediate. The formation of a second DMC may occur either in a process similar to the first one or by dimerization of the hemicarbonate formed after releasing the first DMC. In this pathway, the [Me₂(OH)SnO(OMe)SnMe₂]₂ complex is formed. This complex is less reactive than [Me₂Sn(OMe)₂]₂ but still conserves the catalytic activity. Identification of this mechanism suggests that the catalytic action of Me₂SnO can be improved by modulating the formation of the final [Me₂(OH)SnO(OMe)SnMe₂]₂ complex.

Organotin Compounds in Technology and Industry

Organotin compounds find a bigger range of technological and industrial applications than the organic compounds of any other metal. Many of these applications involve catalysis or anticatalysis, often in polymer chemistry, and they have an importance out of all proportion to the tonnage of tin which is used. This article reviews the present standing of the non-biological applications of organostannanes, with an emphasis on the mechanisms of the reactions which are involved.

The utility of hypercoordination and secondary bonding for the synthesis of a binary organoelement oxo cluster

A strategy for the preparation of the otherwise difficult to obtain binary organometallic oxides containing two heavy main group elements is described and exemplified by the synthesis of [(p-MeOC6H4)2Te(OSnt-Bu2OH)2]2.