Two 1D homochiral heterometallic chains: crystal structures, spectra, ferroelectricity and ferromagnetic properties

Two new homo chiral Cu–Ln (Ln = Gd and Ho) compounds bearing a chiral Schiff base ligand (1R,3S)-N′,N′′-bis[3-methoxysalicylidene]-1,3-diamino-1,2,2-trimethylcyclopentane (H2L) have been synthesized and characterized by elemental analysis, IR spectroscopic and single-crystal X-ray diffraction techniques. The compounds were found to exhibit 1D zig-zag skeletons with double μ-1,5 bridging dicyanamide anions. Circular dichroism (CD) spectra have been used to verify their chiroptical activities. Magnetic studies suggest that 1 and 2 hold the same magnetic behavior with the dinuclear compounds presenting ferromagnetic interaction. Furthermore, both compounds show ferroelectricity with the remnant polarization (Pr) value of 0.23 and 0.18 μC cm−2 at room temperature, respectively.