Two systems of carbonate complexes are constructed via chemical fixation of atmospheric CO₂, in which solvent-induced different structures and magnetic behaviors are observed.

Three Dy₂ complexes with similar crystal structure have been synthesized. Magnetic studies reveal that they exhibit different magnetic relaxation behaviors, originating from the different chemical environments of the center Dy³⁺ ions with different β-diketonate coligands.

Three Dy₄ clusters based on a flexible and attractive Schiff base ligand HL have been synthesized, and they showed different tetranuclear core arrangements. Magnetic studies reveal that clusters 1–3 display distinct slow relaxation of magnetization.

Herein, ten new linear-shaped Ln^III ₄ and Ln^III ₆ clusters, with the formula [Ln₄(acac)₆L₂(CH₃O)₂(CH₃OH)₄]·xCH₃OH (Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), and Tm (8), Hacac = acetylacetone), [Ln₆(acac)₄L₄(CH₃O)₆]·xCH₃OH (Er (7) and Yb (9)), and [Lu₄(acac)₆L₂(OH)₂]·2CH₂Cl₂ (10), based on a polydentate Schiff base ligand, H₂L, and a β-diketone co-ligand were successfully synthesized and structurally characterized. Single crystal X-ray diffraction measurements reveal that the structures of the clusters 1–6, 8 and 10 are very similar and their central Ln(III) ions are linearly arranged Ln₄; however, the clusters 7 and 9 possess a rare linearly arranged Ln₆. The investigations on the solid-state fluorescence properties show that the clusters 2, 3, 5 and 6 display the characteristic lanthanum luminescence at room temperature. Magnetic studies reveal that weak antiferromagnetic interactions exist between adjacent Gd(III) ions in cluster 4. More importantly, the cluster 4 exhibits significant MCE with the maximum −ΔS_m value of 27.96 J kg⁻¹ K⁻¹ at 2.0 K and 7.0 T, whereas the cluster 6 displays a slow magnetic relaxation behavior under a zero dc field with the effective energy barrier ΔE/k_B = 8.64 K and τ₀ = 6.98 × 10⁻⁶ s.