Figure 9
(Top) A trimeric unit with the hanging contacts (red dashed lines) starting from the O—H and COO− hydrogen-bond donors and acceptors. (Bottom) The extended supramolecular structure, showing three trinuclear complexes above and below the starting unit; the expanded contacts are indicated in gray and the hanging contact is in red. In the images, the counter-ions, the piperonal moieties and H atoms which do not participate in the short contacts have been omitted for clarity. |