Heterodiatomic Multiple Bonding in Group 13: A Complex with a Boron–Aluminum π Bond Reduces CO2

Heterodiatomic multiple bonds have never been observed within Group 13. Herein, we disclose a method that generates (CAAC)PhB=AlCp^3t] ( 1 ), a complex featuring π bonding between boron and aluminum through the association of singlet fragments. We present the properties of this multiple bond as well as the reactivity of the complex with carbon dioxide, which yields a boron CO complex via an unusual metathesis reaction.