title: 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).
authors.affiliation: Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, People's Republic of China.
authors.forename: Chun Shan
authors.initials: CS
authors.lastname: Zhou
authors.forename: Li Li
authors.initials: LL
authors.lastname: Ding
authors.forename: Hang
authors.initials: H
authors.lastname: Zhang
authors.forename: Min Na
authors.initials: MN
authors.lastname: Cao
authors.forename: Xiang Gao
authors.initials: XG
authors.lastname: Meng
mesh_terms: D001557:Benzenesulfonates; D001562:Benzimidazoles / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D007093:Imidazoles / Q000737:chemistry*; D008958:Models, Molecular; D012459:Salicylates / Q000737:chemistry*
chemical_list: D001557:Benzenesulfonates; D001562:Benzimidazoles; D007093:Imidazoles; D012459:Salicylates; C065541:2,2'-biimidazole; C029899:imidazole; C003366:sulfosalicylic acid