X-ray Diffraction Study of the First Monomeric Dioxygermylene Ge(OCH_2CH_2NMe_2)_2 Stabilized by Two Ge ← N Intramolecular Coordination Bonds: The Influence of Ge ← N Intramolecular Coordination Bonds on the Structure and Packing of Molecules in Cr

摘要

The molecular and crystal structures of the first monomeric dioxygermylene Ge(OCH_2CH_2NMe_2)_2 (I) stabilized by two Ge ← N intramolecular coordination bonds are determined by X-ray diffraction analysis. The Ge ← N bond lengths in two independent molecules are equal to 2.329(2), 2.337(2) and 2.324(2), 2.346(2) A, respectively. The central germanium atom plays the role of a spiro atom between two five-membered heterocycles in the envelope conformation and adopts a trigonal-bipyramidal configuration with a lone electron pair in the equatorial position. Compound I has two planar-chiral isomers which crystallize jointly. Molecules in the crystal have a layered packing (Molecular layers are perpendicular to the [001] direction) composed of four translationally independent equivalent layers. These layers are spaced at 1/4c intervals and displaced with respect to each other by approximately +0.35a, -1/4b, -0.35a, and +1/4b, respectively. The characteristic displacement of the layers and their proper symmetry (pba2) that differs from the symmetry of the crystal (space group P2_12_22_1) determine a large variety of pseudosymmetry operations.