A ruthenium carbolong skeleton with ten carbon atoms

Carbolong complexes, constituting a fundamental class of metallaaromatics, include metallapentalynes and metallapentalenes. While third-row transition metal-based carbolong skeletons exhibit carbon counts spanning 7-12 and 15, those derived from other metals exhibit carbon numbers limited to a narrower range of 7-9. Here, we report the synthesis of a series of ruthenium 10C-carbolong complexes through a [8C+2C] strategy via alkyne insertion into a ruthenium 8C-carbolong complex. These complexes show broad UV-Vis absorptions, and their aromaticity has been revealed by both experimental data and theoretical calculations. This work achieves the longest carbolong skeleton based on a non-third-row transition metal, expanding the structural diversity of carbolong chemistry.