Synthesis and Isolation of a Silylsilicate Containing Two Pentacoordinated Silicon Atoms by Monoprotonation of a Disilicate and Monodeprotonation of a Disilane

A silylsilicate, which is an intermediate in double protonation of a disilicate bearing two sets of a C,O-bidentate ligand at two pentacoordinated silicon atoms to give a disilane, was synthesized and isolated. The X-ray crystallographic analysis of both the silylsilicate and the disilane revealed intramolecular O···Si coordination, giving the silicon atoms pentacoordinated states. In the silylsilicate, the Si1–O2 and Si2–O3 bonds are almost in parallel. Deprotonation of the silylsilicate, which was also prepared by monodeprotonation of the disilane, gave the disilicate. The oxidation potential and UV/vis absorption maximum are both intermediate between those of the disilicate and the disilane, reflecting the changes in the charges

Interconversion among Dianionic, Anionic, and Neutral Compounds Bearing a Bond between Two Pentacoordinated Germanium Atoms

The first dianionic compounds bearing a bond between two pentacoordinated germanium atoms have been synthesized in a stable form as candidates for a core unit to construct unprecedented structures in group 14 element chemistry. X-ray crystallographic analysis and computational study indicated the single-bond character of the Ge–Ge bond. They were reversibly converted to the anionic and neutral Ge–Ge-bonded compounds while maintaining the coordination number of the germanium atoms. The interconversion features changes in structures around the germanium atoms, including changes from a staggered conformation of the Ge–O bonds to a parallel conformation

Interconversion among Dianionic, Anionic, and Neutral Compounds Bearing a Bond between Two Pentacoordinated Germanium Atoms

The first dianionic compounds bearing a bond between two pentacoordinated germanium atoms have been synthesized in a stable form as candidates for a core unit to construct unprecedented structures in group 14 element chemistry. X-ray crystallographic analysis and computational study indicated the single-bond character of the Ge–Ge bond. They were reversibly converted to the anionic and neutral Ge–Ge-bonded compounds while maintaining the coordination number of the germanium atoms. The interconversion features changes in structures around the germanium atoms, including changes from a staggered conformation of the Ge–O bonds to a parallel conformation

Anionic Iron Complexes with a Bond between an Ate-Type Pentacoordinated Germanium and an Iron Atom

The first stable anionic iron(0) complexes bearing an ate-type pentacoordinated germanium­(IV) ligand were synthesized. The X-ray crystallographic analysis shows trigonal-bipyramidal and piano-stool geometries of germanium and iron, respectively. The complexes have moderately electron-rich iron centers and polar Ge–Fe bonds which can be cleaved by oxidation

Anionic Iron Complexes with a Bond between an Ate-Type Pentacoordinated Germanium and an Iron Atom

The first stable anionic iron(0) complexes bearing an ate-type pentacoordinated germanium­(IV) ligand were synthesized. The X-ray crystallographic analysis shows trigonal-bipyramidal and piano-stool geometries of germanium and iron, respectively. The complexes have moderately electron-rich iron centers and polar Ge–Fe bonds which can be cleaved by oxidation