Homochiral Dy₂Zn₂ zero-field single-molecule magnets derived from (<i>R</i>)/(<i>S</i>)-2-methoxy-2-phenylacetic acids

Despite the unique advantages of multifunctional integration at the nanoscale, chiral zero-field single-molecule magnets (SMMs), especially those based on homochiral carboxylic acids, are still difficult to obtain. Herein, homochiral (<i>R</i>)/(<i>S</i>)-2-methoxy-2-phenylacetic acids (<i>R</i>-HMPA)/(<i>S</i>-HMPA) were selected as the bridging ligands to assemble a pair of Dy₂Zn₂ enantiomers based on the Schiff base ligand (<i>E</i>)-2-((2-hydroxy-3-methoxybenzylidene)amino)phenol (H₂L_Schiff), [Dy₂Zn₂(<i>S</i>-MPA)₂(L_Schiff)₄(DMF)₂]·2DMF (<i>S</i>-1) (DMF = <i>N</i>,<i>N</i>-dimethylformamide) and [Dy₂Zn₂(<i>R</i>-MPA)₂(L_Schiff)₄(DMF)₂]·2DMF (<i>R</i>-1), which possess a [Dy₂Zn₂O₆] defective dicubane core. The CD spectra of <i>R</i>-1 and <i>S</i>-1 confirmed their enantiomeric nature and chiral optical activities. Magnetic studies revealed that they are good zero-field SMMs, with a relatively large <i>U</i>_eff/<i>k</i> value of 234.6 K at 0 Oe and an obvious hysteresis loop at 3.0 K; notably, these magnetic properties could be explained using <i>ab initio</i> calculations.