A pair of mononuclear Dy(iii) enantiomers showing single-ion magnetic and ferroelectric propertiesElectronic supplementary information (ESI) available: Table S1 and Fig. S1-S3. CCDC 1583260 (R-1) and 1583261 (S-1). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c8nj01659c

Using enantiopure ligands (-)/(+)-4,5-pinene-2,2′-bipyridine (L R /L S ) to react with Dy(btfa) 3 ·2H 2 O, respectively, a pair of Dy( iii ) enantiomers with the formulae Dy(btfa) 3 L R ( R -1 ) and Dy(btfa) 3 L S ( S -1 , btfa − = 3-benzoly-1,1,1-trifluoroacetonate) were obtained and structurally characterized. Each Dy( iii ) ion in R -1 and S -1 is octa-coordinate and adopts approximately a square-antiprismatic (SAP) geometry with D 4d symmetry. Studies on the magnetic and ferroelectric properties of R -1 were carried out and the investigation results of the magnetic properties revealed that it displays a slow magnetic relaxation behavior under a zero direct-current (dc) field, confirming its single-ion magnetic (SIM) characteristic with an effective energy barrier of 95.4(1.5) K. Moreover, R -1 crystallizes in the ferroelectric point group C 1 , and exhibits ferroelectricity with a notable remnant polarization ( P r ) value of 3.75 μC cm −2 at room temperature. All these research results also suggested that R -1 and S -1 are potential multifunctional molecule-based materials combining chiroptical activities, and ferroelectric and SIM properties within one molecule. A new pair of Dy( iii )-β-diketonate enantiomers with chiral N,N ′-donor ligands display chiroptical activities and ferroelectric and single-ion magnetic properties, and act as potential multifunctional molecule-based materials.