Two Dy4 complexes, namely, [Dy4(L 1 )4(NO3)2(μ3-OH)2]­·2C2H5OH­·3H2O (1) and [Dy4(L 2 )4(NO3)2(μ3-OH)2]­·3C2H5OH­·8H2O (2), were successfully designed and synthesized under solvothermal conditions. X-ray diffraction results show that both of them display unique {Dy4O8} cores, and the four central Dy­(III) ions are arranged in a regular rhombic frame coplane. Surprisingly, 1 and 2 with a similar structure show the same metal ion coordination environment, but the topological stacking mode has changed drastically due to the introduction of −CH3 into the ligand of 2. Complex 1 shows a fcu network topology with 10 connections, while 2 displays a bcu topology with 8 connections. In addition, magnetic studies revealed that both of them are single-molecular magnets with effective energy barriers of 79.22 and 67.61 K, respectively. Interestingly, complex 2 has undergone a transition from single relaxation of the zero field to two-step relaxation process of the optimal field. The discussion of the magnetic structure relationship in this work provides a good example for exploring the factors affecting magnetic relaxation dynamics.

It is difficult to subject simple reaction starting materials to a “one-pot” in situ tandem reaction without post-treatment under mild reaction conditions to obtain multimers with complex structural linkages. In organic synthesis, acetal reactions are often used to protect derivatives containing carbonyl functional groups. Therefore, acetal products tend to have very low stability, and performing multi-step condensation to obtain complex multimeric products is difficult. Herein, we achieved the first efficient multiple condensation of o-vanillin derivatives using Dy(OAc)3·6H2O undergoing a “one-pot” in situ tandem reaction under mild solvothermal conditions to obtain a series of dimers (I and II, clusters 1 and 2) and trimers (I and II, clusters 3 and 4). When methanol or ethanol is used as the solvent, the alcoholic solvent participates in acetal and dehydration reactions to obtain dimers (I and II). Surprisingly, when using acetonitrile as the reaction solvent, the o-vanillin derivatives undergo acetal and dehydration reactions to obtain trimers (I and II). In addition, clusters 1–4 all showed distinct single-molecule magnetic behaviors under zero-field conditions. To the best of our knowledge, this is the first time that multiple acetal reactions catalyzed by coordination-directed catalysis under “one-pot” conditions have been realized, opening a new horizon for the development of fast, facile, green, and efficient synthetic methods for complex compounds.