An ice-like water hexamer with \overline{3} symmetry in the hydrogen-bonded structure of 2,3,5,6-tetrafluoro-1,4-bis(imidazol-1-ylmethyl)benzene dihydrate

Abstract

An ice-like hexameric water cluster, stabilized by the flexible bis-imidazolyl compound 2,3,5,6-tetrafluoro-1,4-bis(imidazol-1-ylmethyl)benzene (Fbix), is found in the trigonal R3 crystal structure of the title compound, C(14)H(10)F(4)N(4).2H(2)O or Fbix.2H(2)O. The Fbix molecule lies about an inversion centre with one water molecule in the asymmetric unit in a general position. A cyclic chair-like hexameric water cluster with 3 symmetry is generated with a hydrogen-bonded O...O distance within the hexamer of 2.786 (3) A. The Fbix molecule adopts a trans conformation, where the imidazole ring makes a dihedral angle of 70.24 (11) degrees with the central tetrafluorinated aromatic ring. Each water hexamer is connected by six Fbix molecules through intermolecular O-H...N hydrogen bonds [N...O = 2.868 (3) A] to yield a three-dimensional supramolecular network with primitive cubic (pcu) topology. Large voids in each single pcu network lead to fourfold interpenetrated aggregates of Fbix.2H(2)O.