Donor‐Acceptor Activation of Carbon Dioxide

Abstract

The activation and functionalization of carbon dioxide entails great interest related to its abundance, low toxicity and associated environmental problems. However, the inertness of CO2 has posed a challenge towards its efficient conversion to added‐value products. In this review we discuss one of the strategies that have been widely used to capture and activate carbon dioxide, namely the use of donor‐acceptor interactions by partnering a Lewis acidic and a Lewis basic fragment. This type of CO2 activation resembles that found in metalloenzymes, whose outstanding performance in catalytically transforming carbon dioxide encourages further bioinspired research. We have divided this review into three general sections based on the nature of the active sites: metal‐free examples (mainly formed by frustrated Lewis pairs), main group‐transition metal combinations, and transition metal heterobimetallic complexes. Overall, we discuss one hundred compounds that cooperatively activate carbon dioxide by donor‐acceptor interactions, revealing a wide range of structural motifs.

A Blueprint for Secondary Coordination Sphere Editing: Approaches Toward Lewis‐Acid Assisted Carbon Dioxide Co‐Activation

“…Leveraging this cooperativity in molecular complex design, chemists can similarly employ bimetallic complexes for CO 2 activation, [53] where one metal acts as a donor and the other, an acceptor (Lewis‐acid). This approach leads to stabilization of C x H y O z ‐containing intermediates [41] …”

“…One can postulate, however, that it may result from preferential overlap (by similar energy orbitals) between the nucleophilic regions in CO 2 and the electrophilic orbitals of the 2+ cations. This favourable orbital overlap can alternatively be exploited by featuring borane (BR 3 ) groups along with transition metals, which may similarly capture and activate CO 2 due to preferential B−O interactions [41] …”

“…In this Concept , we employ a “bottom‐up” approach to molecular design for the systematic construction of transition metal complexes for CO 2 activation beginning with individual ligand components and moving to completed systems. Of note, Campos and co‐workers, along with others, have contributed complementary reviews on this subject [41–43] . This Concept , however, focuses on CO 2 activation using transition metal complexes which feature intramolecularly‐positioned Lewis‐acids.…”

Activation and functionalisation of carbon dioxide by bis-tris(pyrazolyl)borate-supported divalent samarium and trivalent lanthanide silylamide complexes

“…Carbon dioxide (CO 2 ) activation and functionalisation by complexes of transition metals (TM), 1 rare-earth metals lanthanides (Ln, where Ln = Sc, Y, La–Lu) and actinides, 2 and heterobimetallic systems, 3 have attracted significant interest from scientific communities worldwide, since CO 2 is the largest single source contributor to the greenhouse effect and climate change. CO 2 is a renewable one-carbon ( C 1 ) building block and can bind to metal ions in various ways during activation, 4 which upon functionalisation yields valuable synthetic products and commercially important chemicals.…”

CO2 cleavage by tantalum/M (M = iridium, osmium) heterobimetallic complexes

“…The design of synthetic bimetallic complexes associating different metals with complementary Lewis acidic/Lewis basic behaviour has raised interest for cooperative reactivity, 1–10 including CO 2 activation. 11–17 In many instances, these bifunctional complexes lead to CO 2 adducts or insertion products, in which a bent CO 2 fragment binds across the two metals. 18–27 In contrast, only a few heterobimetallic complexes have clearly exhibited the capability to cleave the C–O bond within CO 2 .…”