Supramolecular architectures built of biimidazole complexes and sulfate or nitrate anions

Four new supramolecular architectures constructed via charge-assisted hydrogen bonds between M2+–H2biim fragments (M = Zn, Cd, and Cu) and inorganic counter-anions (sulfate or nitrate) have been established. Type II (R21(8)) and III (R22(9)) hydrogen bonds have been found to dominate their crystal structure formation. An unusual four-membered water hexamer has been found in 2.

Graphical abstractThe strong affinity of coordinated biimidazole for inorganic counter-anions (sulfate or nitrate) via N–H…O hydrogen bonding has been used as a strategy to build up four different modular assemblies, [Zn(H2biim)3]SO4, [Cu(H2biim)2(H2O)]SO4 · 3H2O, [Cd(H2biim)2(NO3)(H2O)]4(NO3)4 and [Zn(H2biim)2(H2O)](NO3)2. An unusual four-membered water hexamer has been found in 2.Figure optionsDownload full-size imageDownload as PowerPoint slide