Three-dimensional networks in the 1:2 organic salts 2,2′-biimidazolium bis(3-carboxy-4-hydroxybenzenesulfonate) and 2,2′-bibenzimidazolium bis(3-carboxy-4-hydroxybenzenesulfonate) trihydrate

Abstract

The two title compounds of 2,2'-biimidazole (Bim) with 5-sulfosalicylic acid (5-H(2)SSA) and 2,2'-bibenzimidazole (Bbim) with 5-H(2)SSA are 1:2 organic salts, viz. C(6)H(8)N(4)(2+).2C(7)H(5)O(6)S(-), (I), and C(14)H(12)N(4)(2+).2C(7)H(5)O(6)S(-).3H(2)O, (II). The cation of compound (I) lies on a centre of inversion, whereas that of (II) lies on a twofold axis. Whilst compound (I) is anhydrous, three water molecules are incorporated into the crystal structure of (II). The substitution of imidazole H atoms by other chemical groups may favour the incorporation of water molecules into the crystal structure. In both compounds, the component cations and anions adopt a homogeneous arrangement, forming alternating cation and anion layers which run parallel to the (001) plane in (I) and to the (100) plane in (II). By a combination of N-H...O, O-H...O and C-H...O hydrogen bonds, the ions in both compounds are linked into three-dimensional networks. In addition, pi-pi interactions are observed between symmetry-related benzene rings of Bbim(2+) cations in (II).

Cocrystallization of N-donor type compounds with 5-sulfosalicylic acid: The effect of hydrogen-bonding supramolecular architectures

“…Aromatic di-or polycarboxylic acid/N-donor compounds have been applied to achieve various coordination polymers or supramolecules with interesting extended frameworks and properties. As an excellent hydrogen donor and hydrogen acceptor, 5-sulfosalicylic acid (5-H 2 SSA) has been employed in constructing supramolecular architectures with 2,6-diaminopyridine, 1,4-phenylenediamine, 2,2′-biimidazole and 2,2′-bibenzimidazole and so on [16,17]. 5-Sulfosalicylic acid (5-H 2 SSA) has six potential coordination sites in the three functional groups (the sulfonic acid, the carboxylic acid and the hydroxyl groups), and it can give mono-, di-and trianionic ligand species through deprotonation.…”