The chain-shaped coordination polymers based on the bowl-like Ln18Ni24(23.5) clusters exhibiting favorable low-field magnetocaloric effect

Convective heat and mass transfer rate on 3D Williamson nanofluid flow via linear stretching sheet with thermal radiation and heat absorption

A mathematical analysis is communicated to the thermal radiation and heat absorption effects on 3D MHD Williamson nanoliquid (NFs) motion via stretching sheet. The convective heat and mass boundary conditions are taken in sheet when liquid is motion. As a novelty, the effects of thermal radiation, heat absorption and heat and mass convection are incorporated. The aim is to develop heat transfer. Williamson NFs are most important source of heat absorption, it having many significant applications in "energy generation, HT, aircraft, missiles, electronic cooling systems, gas turbines" etc. The suitable similarity transformations have been utilized for reduce basic governing P.D. E's into coupled nonlinear system of O.D. E's. Obtained O.D. Es are calculated by help of R-K-F ("Runge-Kutta-Fehlberg")4th order procedure with shooting technique in MATLAB programming. We noticed that, the skin friction coefficient is more effective in Williamson liquid motion when compared with NFs motion with higher numerical values of stretching ratio parameter, Williamson liquid motion is high when compared to NFs motion for large values of magnetic field. We compared with present results into previous results for various conditions. Finally, in the present result is good invention of previous results.

Platonic and Archimedean solids in discrete metal-containing clusters

Metal-containing clusters have attracted increasing attention over the past 2-3 decades. This intense interest can be attributed to the fact that these discrete metal aggregates, whose atomically precise structures are resolved by single-crystal X-ray diffraction (SCXRD), often possess intriguing geometrical features (high symmetry, aesthetically pleasing shapes and architectures) and fascinating physical properties, providing invaluable opportunities for the intersection of different disciplines including chemistry, physics, mathematical geometry and materials science. In this review, we attempt to reinterpret and connect these fascinating clusters from the perspective of Platonic and Archimedean solid characteristics, focusing on highly symmetrical and complex metal-containing (metal = Al, Ti, V, Mo, W, U, Mn, Fe, Co, Ni, Pd, Pt, Cu, Ag, Au, lanthanoids (Ln), and actinoids) high-nuclearity clusters, including metal-oxo/hydroxide/chalcogenide clusters and metal clusters (with metal-metal binding) protected by surface organic ligands, such as thiolate, phosphine, alkynyl, carbonyl and nitrogen/oxygen donor ligands. Furthermore, we present the symmetrical beauty of metal cluster structures and the geometrical similarity of different types of clusters and provide a large number of examples to show how to accurately describe the metal clusters from the perspective of highly symmetrical polyhedra. Finally, knowledge and further insights into the design and synthesis of unknown metal clusters are put forward by summarizing these "star" molecules.

An isolated doughnut-like molybdenum(V) cobalto-phosphate cluster exhibiting excellent photocatalytic performance for carbon dioxide conversion

An isolated doughnut-like molybdenum(V) cobalto-phosphate cluster with the formula (C₁₁NH₁₀)₂{[Co(H₂O)₆]@[H₂₉Co₁₆Mo₁₆(H₂O)₁₆(PO₄)₂₄O₃₆]}(H₂PO₄)·25H₂O has been successfully synthesized by a hydrothermal method. Single crystal X ray diffraction analysis shows that four {Co₄O₆₀} tetramers and eight {Mo₂O₁₀} dimers are linked by oxygen atoms and phosphate groups to construct a doughnut-type structure for [Co@{Co₁₆Mo₁₆}], in which one [Co^II(H₂O)₆]²⁺ octahedron is enclosed. More importantly, [Co@{Co₁₆Mo₁₆}] exhibits promising photocatalytic performance for CO₂ reduction with the CO formation rate of 6764.3 μmol g^-1 h^-1 and the selectivity of 96.89%. In addition, the cycling test indicated that [Co@{Co₁₆Mo₁₆}] can be reused for at least four cycles without significant loss of catalytic activity. The result of this work may provide new insight for the synthesis of highly efficient POM-based photocatalysts for CO₂ reduction.

Two SiO44--Templated Ln23Ni20 Clusters with Magnetic Cooling and Stability

Assembling and studying high-nuclearity 3d-4f metal clusters represent a pregnant and challenging research hotspot. Based on anionic template and ligand-controlled hydrolytic methods, two heterometallic metal clusters, formulated as [Gd₂₃Ni₂₀(DTA)₂₀(CO₃)₄(CH₃COO)₆(SiO₄)₄(CH₃CH₂OH)₂(μ₃-OH)₃₃(μ₂-OH)₄(H₂O)₁₆]·Cl₂·30H₂O and [Eu₂₃Ni₂₀(DTA)₂₀(CO₃)₄(CH₃COO)₆(SiO₄)₄(CH₃CH₂OH)₂(μ₃-OH)₃₃(μ₂-OH)₄(H₂O)₁₆]·Cl₂·46H₂O (abbreviated as Gd₂₃Ni₂₀, Eu₂₃Ni₂₀, H₂DTA = thiodiglycolic acid), are successfully obtained, which both feature similar double-shell-shaped structures with a Ni₂₀ building unit encapsulating a Ln₂₃ aggregation. The structural analysis illustrates that the SiO₄^4- anion, serving as the anionic template in this work, is reported for the second time in 3d-4f metal clusters. In terms of the magnetic properties, large amounts of Gd³⁺ and Ni²⁺ ions contribute to the MCE of compound Gd₂₃Ni₂₀, along with 38.15 J kg^-1 K^-1 at ΔH = 7.0 T for 2.0 K. It is worth mentioning that compound Gd₂₃Ni₂₀ exhibits an excellent magnetic entropy change at low fields (-ΔS_m = 19.10 J kg^-1 K^-1 at 2.0 K for ΔH = 2.0 T). In addition, Gd₂₃Ni₂₀ exhibits preferable solvent and thermal stability.

A new family of boat-shaped Ln8 clusters exhibiting the magnetocaloric effect and slow magnetic relaxation

Designing and synthesizing lanthanide clusters have always been a research hotspot. Herein, three lanthanide clusters with the formula [Ln₈(IN)₁₄(μ₃-OH)₈(μ₂-OH)₂(H₂O)₈]·xH₂O (Ln = 1-Gd and x = 11; Ln = 2-Dy and x = 8; Ln = 3-Eu and x = 8) have been isolated in the presence of isonicotinic acid under solvothermal conditions. Structural analysis indicates that those three compounds are isostructural, featuring boat-shaped {Ln₈} metal frameworks. Magnetic measurements reveal that 1-Gd exhibits a larger MCE with the maximum -ΔS_m value of 31.77 J kg^-1 K^-1 at 2 K for ΔH = 7 T, while 2-Dy displays slow magnetization relaxation. Besides, the photoluminescence properties of 3-Eu were investigated.