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

Abstract

Six ammonium carboxylate salts, namely cyclopentylammonium cinnamate, C(5)H(12)N(+)·C(9)H(7)O(2)(-), (I), cyclohexylammonium cinnamate, C(6)H(14)N(+)·C(9)H(7)O(2)(-), (II), cycloheptylammonium cinnamate form I, C(7)H(16)N(+)·C(9)H(7)O(2)(-), (IIIa), and form II, (IIIb), cyclooctylammonium cinnamate, C(8)H(18)N(+)·C(9)H(7)O(2)(-), (IV), and cyclododecylammonium cinnamate, C(12)H(26)N(+)·C(9)H(7)O(2)(-), (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 R(4)(3)(10) rings, while salt (I) has a two-dimensional network made up of alternating R(4)(4)(12) and R(6)(8)(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).