Heteronuclear complexes [MDyM](M=Cu; Zn; Ni) constructed by Schiff base ligands with different amine backbone exhibiting significant single-molecule magnets.

• Different electronic and steric effects of amine backbone led to linear-type M-Dy-M, one-dimensional (1D) chain and interlayer-type structures of complexes. • Align the magnetic easy axis of lanthanide ions as closely as possible with the direction of M-M facilitating the mitigation of quantum tunneling of magnetization. • Notable hysteresis loops at maximum temperature of 3.5 K, 7.5 K, and 4 K are observed for Cu 2 Dy, Zn 2 Dy and Ni 2 Dy complexes, respectively. Series of 3d-4f heterotrinuclear complexes [ M Dy M ] (M =Zn, Cu, Ni) with formula [Cu 2 (L1) 2 DyCl 2 (H 2 O)]·Cl·MeCN (1), [Cu 2 (L2) 2 DyCl 2 ] n (2), [Cu 2 (L3) 2 DyCl 2 (MeOH) 2 ]·Cl·(MeOH) 3 (3), [Zn 2 (L1) 2 DyCl 2 (H 2 O)]·Cl·MeCN (4) and [Ni 2 (L1) 2 DyCl 3 ]·(CH 2 Cl 2) 2 (5) were constructed by three hexadentate compartment Schiff bases (L1 = N ,N'-bis(3-methoxysalicylidene)-2,2-dimethylpropane-1,3-diamine; L2 = N ,N'-bis(3-methoxysalicylidene)-1,3-propanediamine; L3 = N ,N'-bis(2‑hydroxy-3-methoxybenzylidene)-1,2-phenylenediamine). Different electronic and steric effects of amine backbone lead to linear-type M -Dy- M , one-dimensional (1D) chain and interlayer-type structures of complexes 1 – 5 , respectively. Among these, complexes 1, 4 and 5 were constructed as the M -Dy- M linear-type coordination configuration containing diamagnetic zinc(II) ions and paramagnetic copper(II) ions or nickel(II) ions respectively. Molecular magnetic studies reveal that complexes 1, 4, 5 and chain complex 2 exhibited significant single-molecule magnets (SMMs) behavior and the notable hysteresis loops at maximum temperature of 3.5 K, 3 K, 7.5 K, and 4 K are observed, which are comparable among the outstanding heteronuclear (d/f) SMMs constructed by Schiff base ligands. Series of 3d-4f heterotrinuclear [MDyM] SMMs were constructed, different electronic and steric effects of amine backbone lead to very different structure and displaying significant magnetic relaxation with hysteresis loops at maximum temperature of 3.5 K, 3 K, 7.5 K, and 4 K, respectively, which are comparable among the outstanding heteronuclear (d/f) SMMs constructed by Schiff base ligands. [Display omitted] [ABSTRACT FROM AUTHOR]