Stabilization of Elusive Main Group Oxides

Chemists have extensively investigated the chemistry of main group oxides of carbon (i.e., CO and CO2) and nitrogen (i.e., NO and NO2). However, our knowledge of the corresponding molecular chemistry of simple oxides of silicon and phosphorus is lacking. Specifically, the seemingly pedestrian molecular oxide SiO2, heavier congener of common CO2, featuring a non-coordinated Si=O double bond, was largely unknown until recently. Similarly, the phosphorus analog of NO2 had not been prepared. This begged the question: Is there a synthetic route by which the stabilization of simple oxides of silicon and phosphorus could be synthetically approached? We believe that the answer is “yes”, and we can do so utilizing the carbene-stabilization technique pioneered in our laboratory. The procedure begins with the synthesis of carbene-stabilized diphosphorus and carbene-stabilized disilicon. With these compounds in hand one simply (and carefully) allow them to react with oxidizing agents (O2 and NO2). With careful control and judicious experimental technique one can obtain stabilization of these elusive main group oxides. Oxidation of carbene-stabilized diphosphorus affords a novel compound that contains the P2O4 fragment between two carbenes.

The dual oxidation of carbene-stabilized disilicon yielded even more amazing products: the first attempts at stabilizing “molecular sand”.