Histidine-Controlled Homochiral and Ferroelectric Metal–Organic Frameworks

A new multifunctional enantiopure ligand, (S)-2-(1,8-naphthalimido)-3-(4-imidazole)­propanoate (s-nip), containing a homochiral center derived from l-histidine and a strong π···π stacking 1,8-naphthalimide synthon, has been used to prepare three novel metal–organic frameworks. The frameworks of [Zn­(s-nip)₂]_n (1) and {[Co­(s-nip)₂]·(H₂O)_0.5}_n (2) are isostructural three-dimensional (3D) homochiral supramolecular structures organized one-dimensional (1D) ribbons by strong hydrogen bonds and π···π interactions, which display ferroelectric behavior at room temperature. The complex [Cu­(nia)₂·(H₂O)₅]_n (3) was constructed under a hydrothermal in situ ligand synthesis reaction, in which the new ligand 2-(1,8-naphthalimido)-3-(4-imidazole)­acrylate (nia) was formed from the s-nip ligand via a dehydrogenation reaction. The two-dimensional network of 3 stacks into a 3D structure via π···π interactions resulting in 1D hydrophilic channels.