Donor-Stabilized Germyl Cations. Stable Pentacoordinate Germanium Chloride [PhGe(OCH₂CH₂NMe₂)₂][Cl]

Abstract

Intramolecularly coordinated phenylbis[N-(dimethylamino)ethoxy]germanium chloride (1) has been prepared, and its structure has been investigated by 1H and 13C NMR spectroscopy in solutions and by X-ray diffraction analysis in the crystal. Compound 1 tends to ionize in hydrogen-bond-donor solvents, such as CHCl3, with the formation of the ionic pentacoordinate form [PhGe(OCH2CH2NMe2)2][Cl] (1b) dominating over the neutral hexacoordinate form PhGe(OCH2CH2NMe2)2Cl (1a). Crystals grown from CHCl3 also represent the form 1b. Salt 1b is the first compound stable under ambient conditions containing a free germanium cation of the type [RGeX2]+ (R = Alk, Ar; X = substituent bonded to the germanium atom by a heteroatom: Hal, OR, NR2) without bulky substituents at the germanium atom in the presence of the highly nucleophilic chloride anion.