Square-Planar Ruthenium Alkylidyne Complexes Undergo Stepwise Rather Than Concerted [2 + 2] Cycloadditions with Alkynes.

ABSTRACT: A new entry into square-planar, formally d⁴-configured ruthenium alkylidyne complexes is disclosed, using p-tolyl(trimethylsilyl)diazomethane as a convenient and safe alkylidyne synthon. The method furnished complex 12 supported by an electron-rich PNP-pincer ligand, which undergoes remarkably facile [2 + 2] cycloaddition with electron-rich, electron-deficient, and strained alkynes; these reactions represent the first examples of metallacyclobutadiene formation by a d⁴-configured transition metal alkylidyne complex. Strikingly, however, the cycloadditions proceed by a stepwise mechanism, which stands in marked contrast to the concerted pathway entertained by all prototypical d⁰ and d² Schrock-type alkylidynes, including the molybdenum, tungsten,

SUBMITTER: Cui M 

PROVIDER: S-EPMC12759212 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature