Recent progress in transition metal complexes supported by multidentate ligands featuring group 13 and 14 elements as coordinating atoms

Over the past decade, significant progress has been made in the chemistry of transition metal complexes supported by multidentate chelate ligands, such as pincer-type ligands, in line with the development of active transition metal catalysts. This review summarizes recent progress in this area, with a focus on the incorporation of electropositive Group 13 (B, Al, Ga, and In) and Group 14 (Si and Ge) elements into the supporting multidentate ligands as coordinating atoms. These electropositive element-based ligands afford complexes with unique functionalities, such as remarkably strong σ-donor ability, high trans influence, and σ-acceptor ability, depending on the types of supporting ligands: L-type (2e donor), X-type (1e donor), and Z-type (2e acceptor) ligands. This review mainly covers the synthesis, fundamental properties, and catalysis of the complexes bearing these ligands.