Acta Cryst. (2000). B56, 261-272 [ doi:10.1107/S0108768199012860 ]
Abstract: Co-crystallization of benzene-1,2,4,5-tetracarboxylic acid, C10H6O8, with 4,4'-bipyridyl, C10H8N2, or with hexamethylenetetramine, C6H12N4, from methanol solutions yields in each case a 2:1 salt, [(C10H9N2)+]2·[(C10H4O8)2-] (1) and [(C6H13N4)+]2·[(C10H4O8)2-] (2). In (1) the carboxylate anions lie across centres of inversion, but they contain no intramolecular O-H
O hydrogen bonds: the cations and anions are linked by strong O-HN and N-HO hydrogen bonds into a chain-of-rings, and these chains are further linked into a three-dimensional framework structure by means of C-HO hydrogen bonds and aromatic ![[bold pi]](/logos/entities/pi_bdgif.gif)
stacking interactions. Compound (2) contains two independent three-molecule aggregates, comprising a central anion and two cations, linked to the anion by means of short N-HO hydrogen bonds. One of these aggregates is centrosymmetric, but the other is not, and the two types of anion both form two intramolecular O-HO hydrogen bonds. The two types of three-molecule aggregate, in which all the anions are virtually parallel, are linked by short C-HO hydrogen bonds into a molecular staircase.
Keywords: Supramolecular structures; Hydrogen bonding; Adducts.
 |   Structure factor file (CIF format) (139.1 kbytes) |
| Structure factor file (CIF format) (299.8 kbytes) |
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