C₂O₄²⁻-templated cage-shaped Ln₂₈(Ln = Gd, Eu) nanoclusters with magnetocaloric effect and luminescence

Abstract

The assembly of high-nuclearity lanthanide nanoclusters with favourable magnetocaloric effects suffers from a significant challenge. Herein, two outstanding examples of cage-shaped nanoclusters, namely, [Ln28(IN)25(C2O4)6(HCOO)(μ3-OH)36(µ2-OH)2(H2O)36]·8Br·xH2O (Ln = Gd and Eu; x...

Self-Assembly of Lanthanide–Aluminum Cluster-Organic Frameworks with Magnetocaloric Effect and Luminescence

“…In this regard, it is commonly referred to as the “antenna effect,″ which can enhance their luminescent sensing capability. , Moreover, at a maximum excitation wavelength of 394 nm, Eu 6 Al exhibited a luminescence lifetime of 371.6 μs and a solid-state photoluminescence quantum yield of 6.64% (Figures c and S15). On comparing the reported Eu 28 and Eu 18 featuring HIN ligands, Eu 6 Al showed a longer luminescence lifetime and higher QY, which unambiguously demonstrates that the extension sites of Al III ions in lanthanide metal–organic frameworks could enhance the photoluminescence efficiency. , …”

“…On comparing the reported Eu 28 and Eu 18 featuring HIN ligands, Eu 6 Al showed a longer luminescence lifetime and higher QY, which unambiguously demonstrates that the extension sites of Al III ions in lanthanide metal−organic frameworks could enhance the photoluminescence efficiency. 27,29 Actually, the whole process of ET is quite intricate and includes the major four steps as flowing: the first excited step is achieved owing to the Laporte-allowed as well as spin-allowed ligand-centered absorptions under the UV lamp irradiation; second, through nonradiative intersystem crossing (ISC), the energy of a singlet excited state (S 1 ) is transferred to the lowerenergy triplet excited state (T 1 ) of HIN; third, the process of intramolecular ET from T 1 to Eu III ions occurs concurrently with the population of excited 4f states of Eu III ; finally, the radiative course experiences with its typical line luminescent (as shown in Figure 5d). This observation supplies valuable insights into the emission features of lanthanide−aluminumbased cluster-organic frameworks.…”

“…To date, the time-honored ligand-controlled hydrolysis strategy is the key point to assembling the discrete clusters to multidimensional metal–organic frameworks. − It has been indicated that suitable multidentate ligands play a crucial role in welding and stabilizing lanthanide ions, endowing the framework expansion regularly. − Isonicotinic acid and lengthened isonicotinic acid ligands, as a significant sort of multifunctional bridging ligands, the carboxyl group may impart the oxophilic lanthanide ion aggregate, the pyridine nitrogen atoms as potential extension sites can connect with other lanthanide cores . For example, the sandwich frameworks, characterized by the connection of two separate layered networks ( Ln 18 and Cu 24 ), are formed by HIN ligands .…”

An unprecedented {Y2⊂Y10} type disk-like Y12 nanocluster featuring electroluminescence property in OLED device

“…In the past few decades, great efforts have been devoted to the construction and investigation of the properties of polynuclear rare-earth (RE) clusters owing to not only their intriguing geometrical features and fascinating physical and chemical properties but also their potential applications in the field of single-molecule magnetism (SMM), magnetocaloric materials, catalysis, luminescence devices, etc. 1–5 Although some exclusive polynuclear RE-clusters, especially the lanthanide (Ln) cluster with different nuclear numbers and geometrical features, such as Ln 5 , Ln 10 , Ln 12 , Ln 18 , Ln 20 , Ln 22 , Ln 24 , Ln 27 , Ln 28 , Ln 36 , Ln 37 , Ln 38 , Ln 48 , Ln 60 , Ln 76 , Ln 104 , and Ln 140 , have been reported, 6–21 the rational design and fabrication of exclusive polynuclear RE-clusters with high nuclear number ( n > 10) and specific geometric conformation still remains a formidable challenge owing to the high coordination numbers, versatile coordination geometries of RE 3+ ions, and mutual repulsion effect between the RE 3+ ions with high positive charges. 12,13,22 Furthermore, the assembly process of the polynuclear rare earth clusters is mainly determined by RE 3+ ion hydrolysis, which could produce the hydroxy intermediates for further assembly.…”

“…1–5 Although some exclusive polynuclear RE-clusters, especially the lanthanide (Ln) cluster with different nuclear numbers and geometrical features, such as Ln 5 , Ln 10 , Ln 12 , Ln 18 , Ln 20 , Ln 22 , Ln 24 , Ln 27 , Ln 28 , Ln 36 , Ln 37 , Ln 38 , Ln 48 , Ln 60 , Ln 76 , Ln 104 , and Ln 140 , have been reported, 6–21 the rational design and fabrication of exclusive polynuclear RE-clusters with high nuclear number ( n > 10) and specific geometric conformation still remains a formidable challenge owing to the high coordination numbers, versatile coordination geometries of RE 3+ ions, and mutual repulsion effect between the RE 3+ ions with high positive charges. 12,13,22 Furthermore, the assembly process of the polynuclear rare earth clusters is mainly determined by RE 3+ ion hydrolysis, which could produce the hydroxy intermediates for further assembly. 19 Thus, the construction conditions are always sensitive to the ratio of ligands/RE 3+ ions and other external factors ( i.e.…”