CO₂ Capture by 2‐(Methylamino)pyridine Ligated Aluminum Alkyl Complexes

Abstract

A set of novel, easily synthesized aluminum complexes, Al[κ 2 ‐ N,N ‐2‐(methylamino)pyridine] 2 R (R = Et, i Bu) are reported. When subjected to 1 atm of CO 2 pressure, each hemilabile pyridine arm dissociates and facilitates cooperative activation of the CO 2 substrate reminiscent of a Frustrated Lewis Pair. This reaction has limited precedent for Al/N based Lewis Pair systems, and this is the first system readily shown to sequester multiple equivalents of CO 2 per aluminum center. The ethyl variant then reacts further, inserting a third equivalent of CO 2 into the aluminum alkyl to generate an aluminum carboxylate. Examples of this type of reactivity are rare under thermal conditions. A joint experimental/computational study supports the proposed reaction mechanism.