Abstract
Cationic silane complexes of general structure (POCOP)Ir(H)(HSiR 3) {POCOP = 2,6-[OP(tBu) 2] 2C 6H 3} catalyze hydrosilylations of CO 2. Using bulky silanes results in formation of bis(silyl)acetals and methyl silyl ethers as well as siloxanes and CH 4. Using less bulky silanes such as Me 2EtSiH or Me 2PhSiH results in rapid formation of CH 4 and siloxane with no detection of bis(silyl)acetal and methyl silyl ether intermediates. The catalyst system is long-lived, and 8300 turnovers can be achieved using Me 2PhSiH with a 0.0077 mol % loading of iridium. The proposed mechanism for the conversion of CO 2 to CH 4 involves initial formation of the unobserved HCOOSiR 3. This formate ester is then reduced sequentially to R 3SiOCH 2OSiR 3, then R 3SiOCH 3, and finally to R 3SiOSiR 3 and CH 4.
Original language | English |
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Pages (from-to) | 11404-11407 |
Number of pages | 4 |
Journal | Journal of the American Chemical Society |
Volume | 134 |
Issue number | 28 |
DOIs | |
State | Published - 18 Jul 2012 |
Externally published | Yes |