Reductive Retrocyclization of a Mangana(II)cyclopentasilane to Form Manganese(0) Bis(η 2 -disilene) Complexes.

Ligand-exchange reactions on a mangana(II)cyclopentasilane complex that contains two THF ligands with aryl isocyanides led to the formation of manganese(0) bis(η 2 -disilene) complexes via a retrocyclization. In stark contrast, ligand-exchange reactions with CN t Bu, an N-heterocyclic carbene, or pyridine-based ligands furnished manganese(II) complexes wherein the manganacyclopentasilane framework remained intact. The thermolysis of the obtained bis(η 2 -disilene) complex in the presence of mesityl isocyanide led to the formation of a cyclotetrasilane via the formal dimerization of the two η 2 -disilene moieties. The insertion of a mesityl isocyanide into the Mn-Si β bond results in the formation of a manganese(II) complex supported by a [SiCSi]-type tridentate ligand scaffold.