Received 13 May 2013
The co-crystal, C7H9N4O2+·ClO4-·C20H24O6·3.25H2O, consists of theobrominium (3,7-dimethyl-2,6-dioxo-1H-purin-9-ium) cations, perchlorate anions and dibenzo-18-crown-6 and water molecules. The crown ether is in a bent conformation, in which the planes of the aromatic rings subtend an angle of 63.7 (1)°. Intermolecular O-HO hydrogen bonding between the water molecules and the O atoms of the cyclic ether delimit an empty space reminiscent of a hollow cage. The water molecules are additionally linked to the cations by N-HO hydrogen bonding. One of the positions of the water molecules is occupied only fractionally (25%) and is located outside this framework.
For applications of crown ethers, see: Lehn (1995). For host-guest chemistry of dibenzo-18-crown-6 with nitrogen bases, see: Lämsä et al. (1998). For the crystal structure of dibenzo-18-crown-6, see: Lima et al. (2008).
Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Crystal Impact, 2012); software used to prepare material for publication: SHELXL97.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: NC2312 ).
VK is grateful to the Studienstiftung des Deutschen Volkes for a PhD scholarship.
Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343-350.
Crystal Impact (2012). DIAMOND. Crystal Impact GbR, Bonn, Germany.
Flack, H. D. (1983). Acta Cryst. A39, 876-881.
Lämsä, M., Huuskonen, J., Rissanen, K. & Pursiainen, J. (1998). Chem. Eur. J. 4, 84-92.
Lehn, J.-M. (1995). In Supramolecular Chemistry: Concepts and Perspectives. Weinheim: VCH Verlagsgesellschaft mbH.
Lima, G. M. de, Wardell, J. L. & Harrison, W. T. A. (2008). Acta Cryst. E64, o2001.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Stoe & Cie (1999). X-SHAPE. Stoe & Cie GmbH, Darmstadt, Germany.
Stoe & Cie (2001). X-RED. Stoe & Cie GmbH, Darmstadt, Germany.
Stoe & Cie (2002). X-AREA. Stoe & Cie GmbH, Darmstadt, Germany.