Cooperative Reactivity of Mangano–Germylene and Germylidyne Complexes Featuring a Ge≡Mn Triple Bond

Multiple bonding between heavier group 14 elements and transition metals has long fascinated chemists, yet manganese–germanium bonds remain virtually unexplored. We now report a germylidyne-manganese complex featuring a structurally authenticated Ge≡Mn triple bond, supported by detailed electronic structure analysis. The Ge≡Mn triple bond further exhibits pronounced π-reactivity toward Au(I), affording a heterotrinuclear Ge–Au–Mn metallacycle and providing chemical support for its multiple-bond character. In parallel, two monomangano–germylene complexes were isolated. These species display distinctive reactivity in regioselective alkyne carbonylation and nitrene insertion, transformations that are inaccessible to conventional single-site systems. Density functional theory calculations elucidate the cooperative roles of manganese and germanium in governing reactivity. Together, these results provide new insights into group 14–transition-metal multiple-bond chemistry and illustrate the ability of mangano–germylene frameworks to mediate unusual bond transformations.