A Mo(VI) alkylidyne complex with polyhedral oligomeric silsesquioxane ligands: homogeneous analogue of a silica-supported alkyne metathesis catalyst.

A highly active alkyne metathesis catalyst is realized by replacing the amide ligands of a molybdenum(VI) trisamide alkylidyne complex with silanol groups from incompletely condensed POSS (polyhedral oligomeric silsesquioxane) ligands. This catalyst serves as an effective homogeneous mimic of an amorphous silica-supported catalyst. Reactivities of various catalytic mixtures are reported along with an X-ray structure of the aniline-coordinated amidodisiloxymolybdenum(VI) alkylidyne complex.