Ligand Field Affected Single-Molecule Magnet Behavior of Lanthanide(III) Dinuclear Complexes with an 8‑Hydroxyquinoline Schiff Base Derivative as Bridging Ligand

New dinuclear lanthanide­(III) complexes based on an 8-hydroxyquinoline Schiff base derivative and β-diketonate ligands, [Ln₂(hfac)₄(L)₂] (Ln­(III) = Gd (<b>1</b>), Tb (<b>2</b>), Dy (<b>3</b>), Ho (<b>4</b>), Er (<b>5</b>)), [Ln₂(tfac)₄(L)₂] (Ln­(III) = Gd (<b>6</b>), Tb (<b>7</b>), Dy (<b>8</b>), Ho (<b>9</b>)), and [Dy­(bfac)₄(L)₂·C₇H₁₆] (<b>10</b>) (L = 2-[[(4-fluorophenyl)­imino] methyl]-8-hydroxyquinoline, hfac = hexafluoroacetylacetonate, tfac = trifluoroacetylacetonate, and bfac = benzoyltrifluoroacetone), have been synthesized. The single-crystal X-ray diffraction data show that complexes <b>1</b>–<b>10</b> are phenoxo-<i>O</i>-bridged dinuclear complexes; each eight-coordinated center Ln­(III) ion is in a slightly distorted dodecahedral geometry with two bidentate β-diketonate coligands and two μ₂-O bridging 8-hydroxyquinoline Schiff base derivative ligands. The magnetic study reveals that <b>1</b> and <b>6</b> display cryogenic magnetic refrigeration properties, whereas complexes <b>3</b>, <b>8</b>, and <b>10</b> show different SMM behaviors with energy barriers of 6.77 K for <b>3</b>, 19.83 K for <b>8</b>, and 25.65 K for <b>10</b>. Meanwhile, slow magnetic relaxation was observed in <b>7</b>, while no out-of-phase alternating-current signals were found for <b>2</b>. The different dynamic magnetic behaviors of two Tb₂ complexes and the three Dy₂ complexes mainly derive from the tiny crystal structure changes around the Ln­(III) ions. It is also proved that the β-diketonate coligands can play an important role in modulating magnetic dynamics of the lanthanide 8-hydroxyquinoline Schiff base derivative system