title: Theobrominium perchlorate dibenzo-18-crown-6 3.25-hydrate.
abstract: The co-crystal, C7H9N4O2 (+)·ClO4 (-)·C20H24O6·3.25H2O, consists of theobrominium (3,7-di-methyl-2,6-dioxo-1H-purin-9-ium) cations, perchlorate anions and dibenzo-18-crown-6 and water mol-ecules. The crown ether is in a bent conformation, in which the planes of the aromatic rings subtend an angle of 63.7 (1)°. Inter-molecular O-H⋯O hydrogen bonding between the water mol-ecules and the O atoms of the cyclic ether delimit an empty space reminiscent of a hollow cage. The water mol-ecules are additionally linked to the cations by N-H⋯O hydrogen bonding. One of the positions of the water molecules is occupied only fractionally (25%) and is located outside this framework.
authors.affiliation: Institut für Anorganische Chemie, Universität zu Köln, Greinstrasse 6, D-50939 Köln, Germany.
authors.forename: Vladislav
authors.initials: V
authors.lastname: Kulikov
authors.forename: Gerd
authors.initials: G
authors.lastname: Meyer
references.citation: Acta Crystallogr A. 2008 Jan;64(Pt 1):112-22
references.pmid: 18156677
references.citation: Acta Crystallogr Sect E Struct Rep Online. 2008 Sep 24;64(Pt 10):o2001
references.pmid: 21201199