Transition-metal complexes with triple bonds to Si, Ge, Sn, and Pb and relevant complexes

Transition-metal complexes featuring triple bonds to heavier Group 14 elements (Si, Ge, Sn, and Pb), which have long been synthetic challenges in organometallic chemistry, have been synthesized in the last few decades. In this highlight, synthetic methods for numerous kinds of complexes and their structural properties are overviewed. Application leading to new multiple bonded systems with M≅GeGe≅M, M≅SiM, and M=Si=M linkages, and to relevant metallotetrylenes are also highlighted.