Three Pairs of Chiral Schiff Base Lanthanide Complexes Exhibiting Single‐Molecule Magnet, Fluorescence and SHG Properties

Multifunctional single‐molecule magnets (SMMs) that combine chirality and fluorescence properties have attracted considerable attention. In this work, the chiral Salen‐type Schiff base ligands H 2 L (H 2 L = (S,S/R,R)‐N,N′‐bis(3‐methoxysalicylidene)cyclohexane‐1,2‐diamine) are utilized to construct three pairs of enantiomeric chiral lanthanide complexes, namely {[Zn(NO 3 )(L)Ln(DMF)(NO 3 ) 2 ]·[EtOH]} 2 ( 1Dy S , Ln = Dy, L = L S ; 1Dy R , Ln = Dy, L = L R ; 2Yb S , Ln = Yb, L = L S ; 2Yb R , Ln = Yb, L = L R ) and [Zn(DMF)(L)Eu(NO 3 ) 3 ] 2 ( 3Eu S , L = L S ; 3Eu R , L = L R ). Single‐crystal X‐ray diffraction and circular dichroism characterizations confirm their chirality and optical activity. All six complexes exhibit the second harmonic generation (SHG) signal. Additionally, fluorescence studies demonstrate that the complexes exhibit strong temperature‐dependent fluorescence emission, characteristic of the typical narrow emission bands of lanthanide ions. In addition, the presence of Dy III ions and Yb III ions endows complexes 1Dy S – 2Yb R with SMM behavior, showing the effective energy barriers of 106.36 K ( 1Dy S ), 92.22 K ( 1Dy R ), 11.46 K ( 2Yb S ), and 18.12 K ( 2Yb R ), respectively.