ABSTRACT
In the crystal structure of the title compound, C(8)H(5)FO(4), the complete molecule is generated by crystallographic twofold symmetry with two C atoms and the F atom lying on the axis. The mol-ecule is almost planar with the carboxyl group twisted with respect to the mean plane of the benzene ring by a dihedral angle of 2.01â (1)°. In the crystal, inter-molecular O-Hâ¯O hydrogen bonds and C-Hâ¯F inter-actions connect the mol-ecules into a two-dimensional supra-molecular array.
ABSTRACT
Entangled nets in coordination compounds with both self-penetrating and interpenetrating structural features have been first constructed by using a flexible bis-pyridinecarboxamide and isophthalate or 5-methylisophthalate. Distinct entangled systems showing both 3-fold interpenetration and polyrotaxane can also be obtained by altering the 5-substituents of isophthalate.
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.
