sp-Hybridized Seesaw Ge

We report the first examples of two linear trigermanium complexes (μ-Ge)(κ2-N2Ge2Ar) (Ar = 2,4,6-Me3C6H2 (4), 2,6-Et2C6H3 (5)), in which each central Ge0 atom displays a seesaw geometry enforced by a four-electron cyclic N2Ge2Ar ligand. The pyridine-stabilized sp-hybridized Ge0 center is a four-electron donor and two terminal germylenes are electron-acceptors. Comparative studies show that the N2Ge2 scaffold uniquely stabilizes the Ge0 atom. This work not only introduces a new class of main-group seesaw complexes but also demonstrates ligand-driven control over hybridization and donor-acceptor dynamics. Compound 5 underwent one-electron reduction, followed by ligand rearrangement and dimerization, to afford a novel hexanuclear homounivalent germanium cluster, 10, featuring a snake-like Ge6 core. In 10, each Ge atom in the central GeI-GeI unit is solely stabilized one amido ligand, while each of the remaining four Ge atoms is supported by one amido and one pyridyl donor. The isolation of a bulkier analogue (11) and a heteronuclear Ge4Sn2 cluster (16) further underscores the crucial role of ligand sterics in stabilizing these assemblies. These findings expand the structural diversity of low-valent group 14 compounds and establish a new paradigm for constructing multinuclear tetrel clusters.