Hexaaryltetragermabuta-1,3-diene: A Molecule with Conjugated Ge−Ge Double Bonds

The longest wavelength absorption of the dark blue solution of the tetragermabutadiene 1 (Tip=2,4,6-iPr3C6H2) in n-hexane at 560 nm indicates a pronounced conjugation of the two Ge−Ge double bonds. In the crystal, 1 adopts the s-cis conformation with a dihedral angle for the Ge4 framework of 22.5°.