Intra- and supra­molecular inter­actions in cis,mer-diaqua­tris­(1H-imidazole-κN³)(terephthalato-κO)cobalt(II) monohydrate

In the title compound, [Co(C₈H₄O₄)(C₃H₄N₂)₃(H₂O)₂]·H₂O, the cisoid angles are in the range 85.59 (5)–93.56 (5)°, while two equal transoid angles deviate significantly from the ideal linear angle, the third being almost linear. One carboxyl­ate group is almost coplanar [1.23 (13)°] with the plane of its parent aromatic ring, although it has one O-atom donor involved in one coordination and one hydrogen bond as acceptor. The other carboxyl­ate group does not coordinate and is rotated out of this plane with a torsional twist of 17.27 (20)°. The coordination neutral entity, based on aqua ligands and two cyclic co-ligands seems, at first sight, monomeric. Strongly tight, via one intra­molecular hydrogen bond between aqua and carboxyl­ate O atoms, it brings out a quasi-planar six-membered ring around the Co^II atom, turning the CoN₃O₃ coordination octa­hedron into a new building block. The rigidity of this feature associated with several hydrogen-bonded arrays yields an extended structure. In the resulting supra­molecular packing, a binuclear hydrated Co^II assembly, built up from triple strands driven by different heterosynthons, embodies the synergy of coordination, covalent and hydrogen bonds.

L-Leucinium fluoride monohydrate

The asymmetric unit of the title hydrated salt, C₆H₁₄NO₂⁺·F⁻·H₂O, contains a discrete cation with a protonated amino group, a halide anion and one water mol­ecule. The crystal structure is composed of double layers parallel to (010) held together by N—H...O, N—H...F, O—H...F and C—H...F hydrogen bonds, forming a two-dimensional network, and stacked along the c axis, viz. hydro­philic layers at z = 0 and 1/2 and hydro­phobic layers at z = 1/3 and 2/3.

DL-Tyrosinium chloride dihydrate

In the title compound, C₉H₁₂NO₃⁺·Cl⁻·2H₂O, the cation has a protonated amino group resulting from proton transfer from chloridric acid. The structure displays double layers parallel to the [010] direction held together by N—H...O, N—H...Cl, O—H...O and O—H...Cl hydrogen bonds. These layers are stacked along the c axis at b = 1/2; within each layer, the tyrosinium cations are arranged in an alternating head-to-tail sequence, forming inversion dimers [R₂²(10) motif]. The water mol­ecules allow for the construction of a three-dimensional hydrogen-bonded network formed by centrosymmetric R₆⁶(28) and R₈⁸(34) motifs.

Bis(adeninium) bis­(hydrogensulfate) sulfate

The title compound, 2C₅H₇N₅²⁺·2HSO₄⁻·SO₄²⁻, was synthesized from adenine and sulfuric acid. The asymmetric unit contains two diprotonated adeninium cations, two bis­ulfate anions and one sulfate anion. The crystal structure is stabilized by classical N—H...O and O—H...O hydrogen bonds, and weak C—H...O and C—H...N hydrogen bonds, generating a three-dimensional network.