Modulating Two Pairs of Chiral Dy III Enantiomers by Distinct β-Diketone Ligands to Show Giant Differences in Single-Ion Magnet Performance and Nonlinear Optical Response.

Using Dy(dbm) 3 (H 2 O) and Dy(btfa) 3 (H 2 O) 2 to react with enantiopure N -donors, (-)/(+)-4,5-pinenepyridyl-2-pyrazine (L R /L S ), respectively, two pairs of chiral Dy III enantiomers, Dy(dbm) 3 L R /Dy(dbm) 3 L S ( R -1-Dy / S -1-Dy ) and Dy(btfa) 3 L R /Dy(btfa) 3 L S ( R -2-Dy / S -2-Dy ) were obtained, wherein one of the benzene rings of dbm - (dibenzoylmethanate) in R -1-Dy / S -1-Dy is displaced by the -CF 3 group of btfa - (4,4,4-trifluoro-1-phenyl-1,3-butanedionate) in R -2-Dy / S -2-Dy . Interestingly, this substitution results not only in giant differences in their single-ion magnetic (SIM) performances but also in their completely different nonlinear optical (NLO) responses. R -1-Dy presents a large effective energy barrier ( U eff = 265.47 K) under zero applied field, being more than 4 × R -2-Dy (61.40 K). The discrepancy on their magnetic performances has been further elucidated by ab initio calculations. Meanwhile, R -1-Dy/ S -1-Dy display the strongest third-harmonic generation responses (35/33 × α-SiO 2 ) among the known lanthanide NLO-active coordination compounds (CCs). On the contrary, R -2-Dy/ S -2-Dy exhibit moderate second-harmonic generation responses (0.65/0.70 × KDP). These results not only give the first example of the CCs with both SMM/SIM behavior and a THG response but also provide an efficient strategy for achieving the function regulation and switch in multifunctional CCs.