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.