Adducts of meso and racemic 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane with trigonally trisubstituted benzene carboxylic acids: supramolecular structures in one and two dimensions

Abstract

The meso and racemic forms of 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, C16H36N4 (tet-a and tet-b, respectively), form adducts with trigonally trisubstituted benzene carboxylic acids; tet-a–3,5-dinitrobenzoic acid (1/2) (1), tet-a–5-hydroxyisophthalic acid–water (1/1/1) (3) and tet-b–5-hydroxyisophthalic acid–water (1/1/1) (4) are all salts, [C16H38N4]2+·2[C7H3N2O6]− (1) and [C16H38N4]2+·[C8H4O5]2−·H2O (3) and (4). The conformations of the [(tet-a)H2]2+ and [(tet-b)H2]2+ cations are entirely different: [(tet-a)H2]2+ is precisely centrosymmetric in (1) and approximately so in (3), while [(tet-b)H2]2+ has approximate C 2 symmetry in (4). In each salt the cation forms two intramolecular N—H...N and four intermolecular N—H...O hydrogen bonds. In (1) the supramolecular structure is one-dimensional, a C 2 2(13)[R 2 4(16)] chain of rings. Compounds (3) and (4) crystallize in space groups P212121 and P21/c, respectively, but the supramolecular structures are very similar: in each, the anions and the water molecules form a C(7)[R 3 3(13)] chain of rings, generated in (3) by a 21 axis and in (4) by a glide plane. These chains are linked, in both (3) and (4), by cations to form sheets. Adjacent meso cations in (3) are related by a 21 axis and adjacent chiral cations in (4) are related by a glide plane.