Supramolecular Architectures Constructed from Piperazine and Substituted Benzoic Acids

Piperazine (pip) were reacted with benzoic acid (Hba) and different substituted benzoic acid, such as o-chlorobenzoic acid (Hocba), m-chlorobenzoic acid (Hmcba), p-chlorobenzoic acid (Hpcba), o-aminobenzoic acid (Hoaba), p-aminobenzoic acid (Hpaba), affording a series of compounds [H(2)pip][ba](2) (1), [H(2)pip][ocba](2) (2), [H(2)pip][mcba](2) (3), [H(2)pip][pcba](2) (4), [H(2)pip][oaba](2) (5), and [H(2)pip][paba](2) (6). Extensive N-H center dot center dot center dot O hydrogen bonds are found in 1-6, featuring different hydrogen-bonding motifs. Compounds 1-4 have two-dimensional layers stabilized by strong N-H center dot center dot center dot O hydrogen bonds, while compounds 5 and 6 exhibit one-dimensional ribbons formed by N-H center dot center dot center dot O hydrogen bonds. Moreover, in compound 6, the existence of water molecules extends the one-dimensional ribbons into a three-dimensional supramolecular structure via hydrogen bonds. CCDC: 672374, (1); 672375, (2); 672376, (3); 672377, (4); 672378, (5); 672379, (6).