Unprecedent formation of methylsilylcarbonates from iridium-catalyzed reduction of CO 2 with hydrosilanes.

The iridium complex [Ir(μ-CF 3 SO 3 )(κ 2 -NSi Me2 ) 2 ] 2 (3) (NSi Me2 = {4-methylpyridine-2-yloxy}dimethylsilyl) has been prepared by reaction of [Ir(μ-Cl)(κ 2 -NSi Me2 ) 2 ] 2 (1) with two equivalents of AgCF 3 SO 3 . The solid structure of 3 evidenced its dinuclear nature, being a rare example of an iridium species with triflate groups acting as bridges. The 3-catalyzed reduction of CO 2 with HSiMe(OSiMe 3 ) 2 affords a mixture of the corresponding silylformate and methoxysilane together with the silylcarbonate CH 3 OCO 2 SiMe(OSiMe 3 ) 2 (4a). This is the first time that the formation of silylcarbonates has been observed from the catalytic reduction of CO 2 with silanes. Analogous behaviour has been observed when HSiMe 2 Ph and HSiMePh 2 were used as reductants.