2,2,3,3,5,5,6,6-Octa-p-tolyl-1,4-dioxa-2,3,5,6-tetragermacyclohexane dichloromethane disolvate

The title compound, C56H56Ge4O2·2CH2Cl2 or Tol8Ge4O2·2CH2Cl2 (Tol = p-CH3C6H4), was obtained serendipitously during the attempted synthesis of a branched oligogermane from Tol3GeNMe2 and PhGeH3. The molecule contains an inversion center in the middle of the Ge4O2 ring which is in a chair conformation. The Ge—Ge bond distance is 2.4418 (5) Å and the Ge—O bond distances are 1.790 (2) and 1.785 (2) Å. The torsion angles within the Ge4O2 ring are −56.7 (1) and 56.1 (1)° for the Ge—Ge—O—Ge angles and −43.9 (1)° for the O—Ge—Ge—O angle.

The title compound, C 56 H 56 Ge 4 O 2 Á2CH 2 Cl 2 or Tol 8 Ge 4 O 2 Á-2CH 2 Cl 2 (Tol = p-CH 3 C 6 H 4 ), was obtained serendipitously during the attempted synthesis of a branched oligogermane from Tol 3 GeNMe 2 and PhGeH 3 . The molecule contains an inversion center in the middle of the Ge 4 O 2 ring which is in a chair conformation. The Ge-Ge bond distance is 2.4418 (5) Å and the Ge-O bond distances are 1.790 (2) and 1.785 (2) Å . The torsion angles within the Ge 4 O 2 ring are À56.7 (1) and 56.1 (1) for the Ge-Ge-O-Ge angles and À43.9 (1) for the O-Ge-Ge-O angle.

Related literature
The related phenyl-substituted derivative Ph 8 Ge 4 O 2 (Drä ger & Hä berle, 1985) is essentially isostructural with the title compound. (1), are the same within experimental error as those in (2) (1.786 (1) and 1.781 (2) Å). The Ge -Ge single bond distance in (1) is 2.4418 (5) Å and is slightly shorter than that in (2) (2.448 (1) Å). The Ge1-C21 bond distance of 1.953 (3) Å is elongated relative to the remaining three Ge -C ipso bonds, which are all the same within experimental error. The Ge -C ipso bonds are nearly identical to those in the phenyl-substituted derivative (2).
Part of the crystal structure is shown in Fig. 2. One germanium atom of two of the four symmetry related molecules shown lies within the selected unit cell, while a germanium atom and an oxygen atom in the remaining two molecules lie within this unit cell. The distances between the centroids of the Ge4O2 rings are 10.78 (1) Å parallel to the a axis and 111.91 (1) Å parallel to the b axis.

Experimental
The title compound (1) was unexpectedly obtained during the attempted preparation of (Tol 3 Ge)3GePh (Tol = pCH 3 C 6 H 4 ) from Tol 3 GeNMe 2 and PhGeH 3 . The crude reaction mixture was recrystallized from dichloromethane which yielded a three X-ray quality crystals, all of which were determined to be compound (1).

Refinement
All hydrogen atoms were placed in calculated positions using a riding-model. Their positions were constrained realtive to their parent atom using the appropriate HFIX instruction in SHELXL97 (Sheldrick, 2008 Fig. 1. The molecular structure of (1), with displacement ellipsoids drawn at the 50% probability level. Primed atoms are related by the symmetry operator (-x, -y, -z+1).  (1), viewed approximately along the c axis.