2,8,15,18,21,24,31,37,44,47,50,53-Dodecaoxaheptacyclo[52.4.0.04,35.06,33.09,14.025,30.038,43]octapentaconta-1(54),4,6(33),9(14),10,12,25(30),26,28,34,38(43),39,41,55,57-pentadecaene dichloromethane disolvate

In the title compound, C46H50O12·2CH2Cl2, each dual 20-crown-6 unit crystallizes with two dichloromethane solvent molecules. The crown unit molecule lies about an inversion centre located at the central benzene ring. The two crown ring groups adopt an anti conformation, stabilized by weak intramolecular C—H⋯O interactions. In the crystal, the crown unit molecules and the solvent molecules are linked by C—H⋯O interactions into a three-dimensional network.

In the title compound, C 46 H 50 O 12 Á2CH 2 Cl 2 , each dual 20crown-6 unit crystallizes with two dichloromethane solvent molecules. The crown unit molecule lies about an inversion centre located at the central benzene ring. The two crown ring groups adopt an anti conformation, stabilized by weak intramolecular C-HÁ Á ÁO interactions. In the crystal, the crown unit molecules and the solvent molecules are linked by C-HÁ Á ÁO interactions into a three-dimensional network.

Chemical context
In a previous article we reported the synthesis and complexation behavior of common-nuclear bis-crown ethers (Lee et al., 1992(Lee et al., , 1997. Within this context we also reported the precursor of the common-nuclear biscrown ether, bearing three aromatic subunits (Lee et al., 2009;Beack et al., 2012). The reaction of 1,2,4,5-tetrakis(bromomethyl)benzene and bisphenol in the presence of sodium hydride afforded the title compound, C 46 H 50 O 12 , that crystallizes with two molecules of dichloromethane.

Structural commentary
In the title molecule ( Fig. 1), in the A-to-B ring and A-to-C ring connectivities, the torsion angles C2-C3-O1-C4 and C23-C22-O6-C21 are -72.7 (3) ° and 99.0 (3)°, respectively. This indicates that the A ring is situated gauche to the B ring, also situated gauche to the C ring, with dihedral angles of 81.64 (14)° between A and B and 81.16 (14)° between A and C. The dihedral angle between the B and C ring is 1.92 (15)°. All C-C-O-C torsion angles in the triethylene glycol group are related to trans conformations. Weak intramolecular C-H···O hydrogen bonds (C22-H22B···O1; C1-H1A···O6) stabilize the conformation of the crown unit molecule (Fig. 1, Table 1).

Supramolecular features
In the crystal, the crown unit molecules and the solvent molecules are linked by C-H···O interactions (Figs. 1, 2; Table   1). The C atom of the dichloromethane molecule (C24) is shifted by 2.383 Å outwards to the crown ring cavity (least squares plane defined by atoms O1-O6), and forms two C-H···O hydrogen bonds with two O atoms (O3 and O6) in the crown ring (Fig. 1, Table 1).

Synthesis and crystallization
To a refluxing suspension of sodium hydride (10.6 mmol) in THF under nitrogen was added dropwise a solution of 1,2,4,5-tetrakis(bromomethyl)benzene (2.20 mmol) and 1,8-bis(2-hydroxyphenoxy)-3,6-dioxaoctane (4.40 mmol) in THF over a period of 3 h. The mixture was then refluxed for additional 3 days. After cooling to room temperature, 10% wt aqueous hydrochloric acid was added. The solvent was removed under reduced pressure and the residual mixture was extracted with dichloromethane. The organic layer was washed with water, dried over anhydrous magnesium sulfate, and evaporated in vacuo. The crude product was chromatographed on a silica-gel column using a mixed solvent of ethyl acetate and n-hexane (1:1) as eluent. Recrystallization from dichloromethane/n-hexane (1:20, v/v) resulted in 53% yield

Refinement details
All H-atoms were positioned geometrically and refined using a riding model with d(C-H)=0.95 Å, U iso =1.2U eq (C) for aromatic and 0.99 Å, U iso =1.2U eq (C) for CH 2 atoms. Reflection (110) was affected by the beamstop and was omitted from the refinement.

Figure 1
The molecular entities of the title compound with the atom numbering scheme and C-H···O interactions (dotted lines).  Crystal packing of the title compound with intra-and intermolecular C-H···O hydrogen bonds shown as dashed lines.