Inorganic heterocycles based on alumosilicate-sulfide ligand

The alumosilicate sulfide ligand [LAl(SH)(μ-O)Si(OH)(OtBu)2] (L = HC[CMeNAr]2−, Ar = 2,6-iPr2C6H3) was used for the preparation of cyclic compounds with the aluminum atom covalently bonded to oxygen and sulfur atoms. The reaction of this ligand with trimethylaluminum or trimethylgallium resulted in the formation of [{LAl(μ-S)(μ-O)Si(μ-O)(OtBu)2}MMe(thf)] (M = Al, Ga) with AlMSiO2S inorganic cores. While the aluminum derivative is stable, the gallium compound always coexists with the tetrametallic species [LAl(μ3-S)(GaMe3)(μ-GaMe2)(μ-O)Si{(μ3-O)(GaMe2)}(μ-OtBu)(OtBu)]. A similar tetrametallic compound can be prepared with aluminum. These compounds represent unprecedented cases of the simplest possible alumosilicate moiety coordinated to three metal atoms. The coordination of three metal atoms to the (tBuO)2Si(μ-O)2 moiety activates one of the Si–O bonds, as evidenced by the bond lengths of 1.684 and 1.703 Å.

The reaction of [LAl(SH)(μ-O)Si(OH)(OtBu)2] (L = HC[CMeNAr]2−, Ar = 2,6-iPr2C6H3) with trimethylaluminum or trimethylgallium led to the formation of bimetallic species [{LAl(μ-S)(μ-O)Si(μ-O)(OtBu)2}MMe(thf)] (M = Al, Ga) with unprecedented covalent M2SiO2S inorganic cores and to the tetrametallic [LAl(μ3-S)(GaMe3)(μ-GaMe2)(μ-O)Si{(μ3-O)(GaMe2)}(μ-OtBu)(OtBu)] compounds. The coordination of three metal atoms to the (tBuO)2Si(μ-O)2 moiety activates one of the Si–OtBu bonds.Figure optionsDownload as PowerPoint slide