Reduction Polymerization of CO 2 with Phenylene Silanes Catalyzed by Single Component B(C 6 F 5 ) 3

CO is an abundant C1 resource but a green-house gas and chemically inert. Thus, its utilization has been a promising but challenging project. Herein, we report the unprecedented polymerization of CO and C H (SiMe H) using B(C F ) alone under mild conditions to give poly(silphenylene siloxane) accompanied by releasing CH . The copolymerization can be extended to comonomers of phenylene silanes bearing functional groups. Moreover, it combines with Piers-Rubinsztajn reaction to establish a tandem polymerization system to achieve super thermal resistant poly(siloxane-co-silphenylene siloxane)s. Density functional theory reveals that B(C F ) is activated by silanes to form free HB(C F ) , which is the true active species for CO reducing to borylformate, the rate controlling step of the polymerization procedure. The subsequent multiple reductions of borylformate to CH and the step-growth to poly(silphenylene siloxane)s can be fulfilled by both B(C F ) and HB(C F ) , and the former shows a slightly higher activity. This work opens a new avenue of utilizing CO to fabricate polysiloxanes that is unable to access using current manners.