ConspectusHigh-nuclearity cluster-type metal complexes are a unique class of compounds, many of which have aesthetically pleasing molecular structures. Their interesting physical and chemical properties arise primarily from the electronic and/or magnetic interplay between the component metal ions. Among the extensive studies in the past two decades, those on lanthanide-containing clusters, lanthanide-exclusive or heterometallic with transition metal elements, are most notable. The research was driven by both the synthetic challenges for these generally elusive species and their intriguing magnetic properties, which are useful for the development of energy-efficient and environmentally friendly magnetic cooling technologies.Our efforts in this vein have been concentrated on developing rational synthetic methods for high-nuclearity lanthanide-containing clusters. By means of the now widely adopted approach of “ligand-controlled hydrolysis” of lanthanide ions, a great variety of cluster-type lanthanide hydro...

High-Nuclearity Lanthanide-Containing Clusters as Potential Molecular Magnetic Coolers.

In-situ synthesis of molecular magnetorefrigerant materials

Recent advances in the assembly of high-nuclearity lanthanide clusters

Despite wide potential applications of Gd-clusters in magnetocaloric effect (MCE) owing to f7 electron configuration of Gd(III), the structural improvement in order to enhance MCE remains difficult. A new approach of the situ hydrolysis of acetonitrile is reported, and the slow release of small ligand CH3COO– is realized in the design and synthesis of high-nuclearity lanthanide clusters. A large lanthanide-exclusive cluster complex, [Gd60(CO3)8(CH3COO)12(μ2-OH)24(μ3-OH)96(H2O)56](NO3)15Br12(dmp)5·30CH3OH·20Hdmp (1-Gd60), was isolated under solvothermal conditions. To the best our knowledge, cluster 1 possesses the high metal/ligand ratio (magnetic density) and the largest magnetic entropy change (−ΔSmmax = 48.0 J kg–1 K–1 at 2 K for ΔH = 7 T) among previously reported high-nuclearity lanthanide clusters.

Exploring the Performance Improvement of Magnetocaloric Effect Based Gd-Exclusive Cluster Gd60

Four seven-nuclearity 3d-4f heterometallic cluster {Fe6LnO28} substituted polyoxometalates (HPz)11K4Fe6Ln(μ3-O)2(B-α-GeW9O34)2(GeW6O26)· xH2O (1-Ln, Pz = piperazine, Ln = Tb, Dy, Ho, Er for x = 27, 25, 25, 24, respectively) have been hydrothermally prepared and structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, infrared spectrometry, thermogravimetric analyses, elemental analyses, and electrospray ionization mass spectrometry. Single-crystal X-ray diffraction analyses revealed that 1-Ln contain an unprecedented banana-shaped polyanion constructed from an iron-lanthanide heterometallic {Fe6LnO28} cluster, two trilacunary {B-α-GeW9O34} units, and one hexalacunary {GeW6O26} fragment. The magnetic susceptibility surveying proved the presence of antiferromagnetic coupling in 1-Ln.

A Series of Banana-Shaped 3d-4f Heterometallic Cluster Substituted Polyoxometalates: Syntheses, Crystal Structures, and Magnetic Properties

Three homometallic high-nuclearity clusters, formulated as [(CO3)2@Ln37(LH3)8(CH3COO)21(CO3)12(μ3-OH)41(μ2-H2O)5(H2O)40]·(ClO4)21·(H2O)100 (abbreviated as Ln37, Ln = Gd (1); Tb (2); Eu (3), LH3 = 1,2,3-cyclohexanetriol) and featuring a double cage-like structure, were obtained through the reaction of 1,2,3-cyclohexanetriol, acetate ligand, and Ln(ClO4)3. The largest odd-numbered lanthanide cluster Gd37 exhibits an entropy change (−ΔSm) of 38.7 J kg–1 K–1.

Three Giant Lanthanide Clusters Ln37 (Ln = Gd, Tb, and Eu) Featuring A Double-Cage Structure.

A series of heterometallic 3d–4f clusters, formulated as Na17[Ln3(H2O)5NiII(H2O)3(Sb4O4)(SbW9O33)3(NiIIW6O24)(WO2)3(CH3COO)]·(H2O)65 [abbreviated as Ln3Ni2, where Ln = La3+ (1), Pr3+ (2), and Nd3+ (3)], K5Na11[Ln3(H2O)3NiII3(H2O)6(SbW9O33)3(WO4)(CO3)]·(H2O)40 [abbreviated as Ln3Ni3, where Ln = La3+ (4), Pr3+ (5), and Nd3+ (6)], and K3Na27[Ln3NiII9(μ3-OH)9(SbW9O33)2(PW9O34)3(CH3COO)3]·(H2O)80 [abbreviated as Ln3Ni9, where Ln = Dy3+ (7) and Er3+ (8)], were obtained through the reaction of the lacunary {SbW9O33} precursor with Ln(NO3)3·6H2O and NiCl2·6H2O in a NaAc/HAc buffer in the presence of different anions. Single-crystal X-ray structure analysis revealed that compounds 1–3 possessed tetrameric architectures featuring three Keggin-type {SbW9O33} and one Anderson-type {NiIIW6O24} building blocks encapsulating one {Sb4O4} cluster, three WO2 units, three Ln3+ metal ions, and two Ni2+ metal ions. Compounds 4–6 displayed cyclic trimeric aggregates of three {SbW9O33} units enveloping one CO32–-templated trinu...

Jing Cai

Papers

Three Giant Lanthanide Clusters Ln37 (Ln = Gd, Tb, and Eu) Featuring A Double-Cage Structure.

Anion-Dependent Assembly of Heterometallic 3d–4f Clusters Based on a Lacunary Polyoxometalate

Cardiac glycosides from the roots of Streblus asper Lour. with activity against Epstein-Barr virus lytic replication.