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Although progress has been made in the design and synthesis of chiral lanthanide clusters with pleasing structural connections and special shapes, assembly rules that guide their directional construction are still lacking. We reacted R/S -mandelic acid hydrazide, 2,3-dihydroxybenzaldehyde and DyCl3·6H2O under solvothermal conditions to obtain two octanuclear chirality clusters R-1 and S-1 , which are the enantiomers of each other. R/S -mandelic acid hydrazide and 2,3-dihydroxybenzaldehyde underwent an in situ reaction under "one-pot" conditions to generate a monohydrazone-type organic ligand R/S -mandelic acid hydrazide-2,3-dihydroxybenzaldehyde hydrazone (R/S -H2L). Four R/S -H2L ligands captured eight metal-centered Dy(III) ions and presented an annular arrangement, which assembled to form a pinwheel-shaped chiral cluster R/S-1. The benzene rings at the four vertices of R/S-1 can rotate freely as rotors. This is the first discovery of an annular growth mechanism during the self-assembly of lanthanide clusters. By changing the metal salt to Dy(NO3)3·6H2O, two twist-shaped hexanuclear clusters R-2 and S-2 , which are the enantiomers of each other were obtained. Four R/S -H2L and two R/S -H3L ligands captured six metal-centered Dy(III) ions, respectively, and were assembled through a linear growth mechanism to form the twist-shaped chiral clusters R/S-2. This is the first time that a linear growth mechanism has been proposed for the directional construction of lanthanide clusters with specific shapes. Circular dichroism results showed that R/S-1 and R/S-2 were both chiral clusters and enantiomers of each other. Magnetic studies showed that both R/S-1 and R/S-2 exhibit obvious single-molecule magnet (SMM) behaviors under zero-field conditions. This work is the first to propose an annular/linear growth mechanism for the design and synthesis of lanthanide clusters and allows the directional construction of chiral lanthanide clusters with special shapes and structural connections. [ABSTRACT FROM AUTHOR]

In the past two decades, tremendous progress has been made in the field of single-molecule magnets (SMMs), which not only achieves breakthroughs in various key indicators (flipping energy barrier and hysteresis temperature), but also expands SMMs of various types (3d, 4f, 3d–4f and 5f) and different connection methods. Among the many different types of SMM mentioned above, the SMM based on the 4f metal center has made the biggest breakthrough. Introducing 3d metal ions into lanthanide complexes to form 3d–4f heterometallic complexes can promote strong magnetic exchange between multiple metal centers, resulting in magnetic properties different from 3d and 4f complexes. Therefore, the expansion of the structure and magnetic properties of 3d–4f heterometallic complexes can promote the progress in the field of SMM. In this review, we summarize the structure and magnetic properties of 3d–4f heterometallic complexes formed by different types of organic ligands. [ABSTRACT FROM AUTHOR]

A dinuclear Dy (III) complex [Dy2(L1)2(NO3)4]·2CH3CN (1) (HL1 = 1,3‐bis{[(E)‐pyridin‐2‐ylmethylene]amino}propan‐2‐ol) was obtained via the reaction of 1,3‐diamino‐2‐propanol, 2‐pyridyaldehyde and Dy (NO3)3·6H2O at room temperature. In the structure of complex 1, two Dy (III) ions are in the N4O6 coordination environment provided by NO3− and (L1)−, and both of these ions are in the sphenocorona configuration. [Dy2(L2)2(NO3)4] (2) [HL2 = 2‐(pyridin‐2‐yl)hexahydropyrimidin‐5‐ol] was obtained using the same reaction material only when the reaction temperature was changed to 60°C. Structural analysis of complex 2 showed that the two Dy (III) ions with the same coordination configuration are in the N3O6 coordination environment provided by NO3− and (L2)− and are in the distorted spherical‐capped square antiprism. Surprisingly, HL2 with the parent of bipyridine was synthesized by the Schiff base reaction of 1,3‐diamino‐2‐propanol with 2‐pyridoxaldehyde followed by the ring‐closing reaction catalyzed by Dy (III) ions. Magnetic measurements of the Dy (III) complexes revealed no obvious frequency‐dependent behavior of complex 1. In contrast, complex 2 showed an obvious frequency dependence (Ueff = 0.49 K and τ0 = 6.62 × 10−4 s) under the condition of zero field and a weak double relaxation behavior (Ueff = 9.25 K and τ0 = 9.70 × 10−4 s) at 1500 Oe. [ABSTRACT FROM AUTHOR]