An efficient iridium catalyst for reduction of carbon dioxide to methane with trialkylsilanes

TY - JOUR

T1 - An efficient iridium catalyst for reduction of carbon dioxide to methane with trialkylsilanes

AU - Park, Sehoon

AU - Bézier, David

AU - Brookhart, Maurice

PY - 2012/7/18

Y1 - 2012/7/18

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=84863915651&partnerID=8YFLogxK

U2 - 10.1021/ja305318c

DO - 10.1021/ja305318c

M3 - 文章

C2 - 22765847

AN - SCOPUS:84863915651

SN - 0002-7863

VL - 134

SP - 11404

EP - 11407

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 28

ER -