Regulating the slow magnetic relaxation behavior of two different shapes Dy4clusters with in situ formed penta‐ and heptadentate Schiff base ligands

The design and synthesis of clusters possessing the same number of cores but different connection methods and properties have always been difficult. Herein, we used 2‐pyridinaldehyde, 1,3‐diamino‐2‐propanol, and Dy (ClO 4 ) 3 ·6H 2 O at room temperature (RT) to obtain the cluster [Dy 4 (L 1 ) 4 ( μ 2 ‐OH) 4 ]·4ClO 4 − ( 1 , HL 1 = 2‐pyridinecarboxaldehyde‐1,3‐diamino‐2‐propanol) with square Dy 4 O 8 cluster cores. Cluster 1 consisted of four Schiff base ligands (L 1 ) − , four Dy(III) ions, four bridged ( μ 2 ‐OH) − , and four free ClO 4 − . The ligand HL 1 was formed by in situ Schiff base reaction with 2‐pyridinecarbaldehyde and 1,3‐diamino‐2‐propanol in the presence of Dy(III) ions. 2‐Aldehyde‐8‐hydroxyquinoline, 1,3‐diamino‐2‐propanol, and Dy (NO 3 ) 3 ·6H 2 O reacted at RT to yield a tetranuclear Dy(III) cluster [Dy 4 (L 2 ) 2 ( μ 3 ‐OH) 2 (NO 3 ) 4 (EtOH) 2 ]·2CH 3 CN ( 2 , H 3 L 2 = 2‐aldehyde‐8‐hydroxyquinoline‐1,3‐diamino‐2‐propanol) with butterfly‐shaped Dy 4 O 6 cluster core. Cluster 2 consisted of two ligands (L 2 ) 3− , four Dy(III) ions, two bridged μ 3 ‐OH, two end‐group‐coordinated ethanol molecules, and four bidentate‐chelated NO 3 − . The in situ reaction of 2‐aldehyde‐8‐hydroxyquinoline and 1,3‐diamino‐2‐propanol under Dy(III) ion‐assisted catalytic conditions provided the ligand H 3 L 2 . It is worth noting that the magnetic test showed that 1 is a typical single‐molecule magnet (SMM), whereas 2 only showed a significant frequency dependence behavior. We considered Orbach and Raman processes ( τ −1 = τ 0 −1 exp(− U eff / k B T ) + CT n ) to fit 1 and 2 in the high‐temperature range and obtained U eff = 7.01 and 5.43 K and τ 0 = 1.18 × 10 −4 and 4.14 × 10 −5 s, respectively.