The effect of co-ligands on the performance of single-molecule magnet behaviours in a family of linear trinuclear Zn-Dy-Zn complexes with a compartmental Schiff base.

We present herein magneto-structural studies of three heterometallic ZnDy complexes: ZnDy(L)Cl(HO)·4HO (1), ZnDy(L)Br(HO)·4HO (2) and [ZnDy(L)(OAc)I(HO)]I·4HO (3), utilizing a new Schiff base ligand, ,-bis(3-methoxy-5-methylsalicylidene)-1,2-diaminocyclohexane (HL). Complexes 1 and 2 exhibit remarkable magnetic relaxation behaviour with relatively high energy barriers in zero field (: 244 K for 1 and 211 K for 2) and notable hysteresis temperatures, despite the low local geometric symmetry around the central Dy ions. The SMM performance of these complexes is further enhanced under an applied magnetic field, with increasing to 309 K for 1 and 269 K for 2, positioning them as elite members within the Zn-Dy SMM family. These findings emphasize the substantial influence of remote modulation on Zn beyond the first coordination sphere of Dy ions on their dynamic magnetic relaxation properties. studies demonstrate that the relative orientation of the phenoxo-oxygen donor atoms around the Dy ion is critical for determining the magnetic anisotropy and relaxation dynamics in these systems. Additionally, experimental and theoretical investigations reveal that the coordination of the bridging acetate towards the hard plane, combined with significant distortion from the ideal ZnODy diamond core arrangement caused by the acetate ion, results in low magnetic anisotropy in complex 3, thereby leading to field-induced SMM behaviour. Overall, this study unveils the effects of co-ligands on the SMM performance in a series of linear trinuclear Zn-Dy-Zn complexes, which exhibit low local geometric symmetry around the Dy centres.