Structural study of six cyclo­alkyl­ammonium cinnamate salt structures featuring one-dimensional columns and two-dimensional hydrogen-bonded networks

Six ammonium carboxyl­ate salts, namely cyclo­pentyl­ammonium cinnamate, C₅H₁₂N⁺·C₉H₇O₂⁻, (I), cyclo­hexyl­ammonium cinnamate, C₆H₁₄N⁺·C₉H₇O₂⁻, (II), cyclo­heptyl­ammonium cinnamate form I, C₇H₁₆N⁺·C₉H₇O₂⁻, (IIIa), and form II, (IIIb), cyclo­octylammonium cinnamate, C₈H₁₈N⁺·C₉H₇O₂⁻, (IV), and cyclo­dodecyl­ammonium cinnamate, C₁₂H₂₆N⁺·C₉H₇O₂⁻, (V), are reported. Salts (II)–(V) all have a 1:1 ratio of cation to anion and feature three N⁺—H...O⁻ hydrogen bonds forming one-dimensional hydrogen-bonded columns consisting of repeat­ing R₄³(10) rings, while salt (I) has a two-dimensional network made up of alternating R₄⁴(12) and R⁶₈(20) rings. Salt (III) consists of two polymorphic forms, viz. form I having Z′ = 1 and form II with Z′ = 2. The latter polymorph has disorder of the cyclo­heptane rings in the two cations, as well as whole-mol­ecule disorder of one of the cinnamate anions. A similar, but ordered, Z′ = 2 structure is seen in salt (IV).

Rietveld refinement of the cocrystal 2,4-dihy­droxy­benzoic acid-N'-(pro­pan-2-yl­idene)nicotinohydrazide (1/1)

A further example of using a covalent-bond-forming reaction to alter supra­molecular assembly by modification of hydrogen-bonding possibilities is presented. This concept was introduced by Lemmerer, Bernstein & Kahlenberg [CrystEngComm (2011), 13, 55-59]. The title structure, C₉H₁₁N₃O·C₇H₆O₄, which consists of a reacted niazid mol­ecule, viz. N'-(propan-2-yl­idene)nicotinohydrazide, and 2,4-di­hy­droxy­benzoic acid, was solved from powder diffraction data using simulated annealing. The results further demonstrate the relevance and utility of powder diffraction as an analytical tool in the study of cocrystals and their hydrogen-bond inter­actions.