Crystal structure of zwitterionic 3,3′-[1,1′-(butane-1,4-di­yl)bis­(1 H-imidazol-3-ium-3,1-di­yl)]bis­(propane-1-sulfonate) dihydrate

Abstract

A known N-heterocyclic carbene precursor, zwitterionic 3,3′-[1,1′-(butane-1,4-di­yl)bis­(1 H-imidazol-3-ium-3,1-di­yl)]bis­(propane-1-sulfonate) crystallized as its dihydrate and was characterized by single-crystal X-ray diffraction, revealing point group symmetry for the zwitterionic mol­ecule.

Abstract

The crystal structure of the title compound, C ₁₆H ₂₆N ₄O ₆S ₂·2H ₂O, a water-soluble di- N-heterocyclic carbene ligand precursor was determined using a single crystal grown by the slow cooling of a hot N, N-di­methyl­formamide solution of the compound. The dihydrate crystallizes in the monoclinic space group P2 ₁/ c, with half of the zwitterionic mol­ecule and one water mol­ecule of crystallization in the asymmetric unit. The remaining part of the mol­ecule is completed by inversion symmetry. In the mol­ecule, the imidazole ring planes are parallel with a plane-to-plane distance of 2.741 (2) Å. The supra­molecular network is consolidated by hydrogen bonds of medium strength between the zwitterionic mol­ecules and the water mol­ecules of crystallization, as well as by π–π stacking inter­actions between the imidazole rings of neighbouring mol­ecules and C—H⋯O hydrogen-bonding inter­actions.