Effect of diamagnetic Zn(II) ions on the SMM properties of a series of trinuclear ZnDy 2 and tetranuclear Zn 2 Dy 2 (Ln III = Dy, Tb, Gd) complexes: combined experimental and theoretical studies.

To study the effect of diamagnetic ions on magnetic interactions, utilizing a compartmental ligand ( Z )-2-(hydroxymethyl)-4-methyl-6-((quinolin-8-ylimino)methyl)phenol (LH 2 ), two different series of Zn II -Ln III complexes, namely the trinuclear series of [DyZn 2 (L) 2 (μ 2 -OAc) 2 (CH 3 OH) 2 ]·NO 3 ·MeOH (1), [TbZn 2 (L) 2 (μ 2 -OAc) 2 (CH 3 OH) 2 ]·NO 3 ·5MeOH·H 2 O (2), and [GdZn 2 (L) 2 (μ 2 -OAc) 2 (CH 3 OH) 2 ]·NO 3 ·MeOH·CHCl 3 (3) and the tetranuclear series of [Dy 2 Zn 2 (LH) 4 (NO 3 ) 4 (μ 2 OAc)]·NO 3 ·MeOH·H 2 O (4), [Tb 2 Zn 2 (LH) 4 (NO 3 ) 4 (μ 2 -OAc)]·NO 3 ·MeOH·2H 2 O (5), and [Gd 2 Zn 2 (LH) 4 (NO 3 ) 4 (μ 2 -OAc)]·NO 3 ·MeOH·2H 2 O (6), were synthesized. Trinuclear Zn II -Ln III complexes 1-3 consist of one Ln III ion sandwiched between two peripheral Zn II ions forming a bent type Zn II -Dy III -Zn II array with an angle of 110.64°. Tetranuclear Zn II -Ln III complexes 4-6 are basically a combination of two dinuclear moieties of [LnZn(LH) 2 (NO 3 ) 2 ] + connected by one bidentate bridging acetate ion in μ 2 -OAc coordination mode. The detailed magnetic analysis reveals that complexes 1 and 4 are single molecule magnets having energy barriers of 34.98 K and 46.71 K with relaxation times ( τ 0 ) of 5.05 × 10 -4 s and 5.24 × 10 -4 s, respectively. Ab initio calculations were employed to analyze the magnetic anisotropy and magnetic exchange interaction between the Zn II and Ln III centers with the aim of gaining better insights into the magnetic dynamics of complexes 1-6.