Dy4 and Dy5 complexes based on tautomeric hydrazone Schiff-base ligand regulated by temperature showing single-molecule magnet behaviour.

• Two dysprosium complexes Dy 4 and Dy 5 based on hydrazone Schiff-base ligand were synthesized, and their structures could be regulated by controlling temperature. • Complex Dy 4 is a typical field-induced single-molecule magnet with an effective energy barrier U eff of 42.9 K under 1 kOe dc field. Complex Dy 5 is a zero dc field single-molecule magnet with an effective energy barrier U eff of 4.18 K. Two dysprosium complexes [Dy 4 (H 2 L) 6 ]⋅4H 2 O (Dy 4) and [Dy 5 (H 2 L)(HL) 2 (L)(µ 3 OH) 2 Cl(H 2 O)(MeCN) 2 ]⋅4MeOH⋅7H 2 O (Dy 5) (H 4 L = (N',N'''E,N',N'''E)-N',N'''-(pyridine-2,6-diylbis(methanylylidene))bis(2-hydroxybenzohydrazide)) based on hydrazone Schiff-base ligand were synthesized, which could be regulated by controlling temperature (Dy 4 , below 293 K and Dy 5 , over 308 K). Magnetic studies show that complex Dy 4 is a typical field-induced single-molecule magnet with an effective energy barrier (U eff) of 42.9 K under 1 kOe dc field. Complex Dy 5 is a zero dc field single-molecule magnet with an effective energy barrier (U eff) of 4.18 K. The results indicate the synthesis of lanthanide complexes is sensitive to substitute of ligand and temperature. Two novel compounds, Dy 4 and Dy 5 , were synthesized by using hydrazone Schiff-base ligand and dysprosium ions. Their structures and single-molecule magnet properties can be regulated by synthetic temperature. [Display omitted] [ABSTRACT FROM AUTHOR]