Small Molecule Activation by Metallylenes and Their Follow-up Reactions

The activation of small molecules is a crucial step in advancing sustainable chemistry, enabling key transformations in fine chemical synthesis and energy storage. While transition metals have traditionally dominated this field, main-group elements—specifically metallylenes, which are heavier analogs of carbenes (silylenes, germylenes, stannylenes, and plumbylenes)—have emerged as viable alternatives due to their unique electronic properties and tunable reactivity. This review explores the mechanisms by which metallylenes activate small molecules, highlighting the influence of ligand design, electronic structure, and geometric factors. We discuss recent advances in the field, including computational insights into metallylene-mediated bond activation and experimental demonstrations of their catalytic potential. Additionally, we examine follow-up reactions such as hydrogenation and hydroboration, which illustrate the versatility of metallylenes in small molecule transformation. By providing a comprehensive overview of the latest developments, this review aims to bridge fundamental principles with potential applications, paving the way for metallylene-based catalysis in sustainable chemistry.