Regulating the slow magnetic relaxation behavior of two different shapes Dy4 clusters with in situ formed penta‐ and heptadentate Schiff base ligands. (23rd May 2020)

• Record Type: Journal Article
• Authors: Zhu, Zhong‐Hong; Wang, Hai‐Ling; Fu, Xiao‐Xiao; Zou, Hua‐Hong; Liang, Fu‐Pei
• Is Part Of: Applied organometallic chemistry. Volume 34:Number 9(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-05-23
• Subjects: room temperature -- Schiff Base ligand -- shapes and connections -- single‐molecule magnet -- tetranuclear Dy(III) cluster; Organometallic chemistry -- Periodicals; Organometallic compounds -- Periodicals; 547.05
• DOI: 10.1002/aoc.5808
• Languages: English
• ISSNs: 0268-2605

Abstract

Abstract : 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 (ClO4 )3 ·6H2 O at room temperature (RT) to obtain the cluster [Dy4 (L 1 )4 ( μ 2 ‐OH)4 ]·4ClO4 − (1, HL 1 = 2‐pyridinecarboxaldehyde‐1, 3‐diamino‐2‐propanol) with square Dy4 O8 cluster cores. Cluster 1 consisted of four Schiff base ligands (L 1 ) −, four Dy(III) ions, four bridged ( μ 2 ‐OH) −, and four free ClO4 − . 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 (NO3 )3 ·6H2 O reacted at RT to yield a tetranuclear Dy(III) cluster [Dy4 (L 2 )2 ( μ 3 ‐OH)2 (NO3 )4 (EtOH)2 ]·2CH3 CN (2, H3 L 2 = 2‐aldehyde‐8‐hydroxyquinoline‐1, 3‐diamino‐2‐propanol) with butterfly‐shaped Dy4 O6 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 NO3 − . 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 H3 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. Abstract : We obtained two cases of tetranuclear Dy(III) clusters possessing different shapes and connections and different single‐molecule magnet properties by regulating Schiff base ligands at RT.