Two- and three-dimensional hydrogen-bonded networks built from 1,3,5-[(HO)2(O)P]3C6H3 and 4-(dimethylamino)pyridine

Crystallisation of 3,5-bis(phosphonophenyl)phosphonic acid, 1,3,5-[(HO)(2)(O)P](3)C6H3, from MeOH/H2O in the presence of 4-(dimethylamino)pyridine, 4-(Me2N)C5H4N, gave [1-{(HO)(2)(O)P}-3,5-{(HO)(O)(2)P}(2)C6H3](2-)[{4-(Me2N)C5H4NH}(+)](2) (2) and [1,3-{(HO)(2)(O)P}(2)-5-{(HO)(O)(2)P}C6H3](-)[4-(Me2N)-C5H4NH](+) (3). Single-crystal X-ray diffraction analyses revealed a two- and a three-dimensional hydrogen-bonded network for compounds 2 and 3, respectively. Compound 2 is composed of layers which are formed by hydrogen-bonded motifs of the type R2,2(8) and R4,4(16). These motifs are connected within the layer by additional hydrogen bonds and the benzene spacer. The cation [4-(Me2N)C5H4NH](+) is located between the layers and determines the interlayer separation of approximately 6.5 Angstrom. In compound 3 a layered network of the hydrogen-bonded building units R2,3(10) was observed. These units are interconnected by four additional hydrogen bonds within the network. The benzene spacer links the adjacent layers to give a three-dimensional structure. Within this network, channels with internal dimensions of ca. 8.5 x 11.3 Angstrom(2) which are occupied by the [4-(Me2N)C5H4NH](+) cations were observed. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.