Multiyne chains chelating osmium via three metal-carbon σ bonds

Although the formation of metal-carbon sigma bonds is a fundamental principle in organometallic chemistry, the direct bonding of one organic molecule with one metal center to generate more than two metal-carbon sigma bonds remains a challenge. Herein, we report an aromaticity-driven method whereby multiyne chains are used to construct three metal-carbon sigma bonds in a one-pot reaction under mild conditions. In this method, multiyne chains act as ligand precursors capable of chelating an osmium center to yield planar metallapolycycles, which exhibit aromaticity and good stability. The direct assembly of various multiyne chains with commercially available metal complexes or even simple metal salts provides a convenient and efficient strategy for constructing all carbon-ligated chelates on the gram scale.