Although great achievements have been made in the synthesis of giant lanthanide clusters, novel structural models are still scarce. Herein, we report a giant lanthanide cluster Dy76, constructed from [Dy3(μ3‐OH)4] and [Dy5(μ4‐O)(μ3‐OH)8] building blocks. As the largest known Dy cluster, the structure of Dy76 can be seen as arising from the fusion of two Dy48 clusters; these clusters can be isolated under various synthetic conditions and were characterized by single‐crystal X‐ray diffraction. This new, fused structural model of the pillar motif has not been found in Ln clusters. Furthermore, the successful conversion of Dy76 back into Dy48 in a retrosynthetic manner supports the proposed fusion formation mechanism of Dy76. Electrospray ionization mass spectrometry (ESI‐MS) analysis suggests that the metal cluster skeleton of Dy76 shows good stability in various solvents. This work not only reveals a new structural type of Ln clusters but also provides insight into the novel fusion assembly process.
Combining Ising-type magnetic anisotropyw ith collinear magnetic interactions in single-molecule magnets (SMMs) is as ignificant synthetic challenge.H erein we report aD y[15-MC Cu-5] (1-Dy)S MM, where aD y III ion is held in ac entral pseudo-D 5h pocket of ar igid and planar Cu 5 metallacrown (MC). Linking two Dy[15-MC Cu-5] units with as ingle hydroxideb ridge yields the doubledecker {Dy[15-MC Cu-5]} 2 (2-Dy)S MM where the anisotropya xes of the two Dy III ions are nearly collinear,resulting in magnetic relaxation times for 2-Dy that are approximately 200 000 times slower at 2Kthan for 1-Dy in zero external field. Whereas 1-Dy and the Y III-diluted Dy@2-Y analogue do not show remanence in magnetic hysteresis experiments,t he hysteresis data for 2-Dy remain open up to 6Kwithout asudden drop at zero field. In conjunction with theoretical calculations,these results demonstrate that the axial ferromagnetic Dy-Dy coupling suppresses fast quantum tunneling of magnetization (QTM). The relaxation profiles of both complexes curiously exhibit three distinct exponential regimes,a nd hold the largest effective energy barriers for any reported d-f SMMs up to 625 cm À1 .
It is a challenge to synthesize metal‐organic frameworks (MOFs) catalysts with high catalytic activity and stability under reaction conditions. For this study, the combinations of two‐dimensional (2D) ultrathin nickel‐organic framework (Ni‐UMOF) with layered graphitic carbon nitride (g‐C3N4) or graphene oxide (GO) as promising composite catalysts for the hydrogenation of 4‐nitrophenol were reported. The ultrathin nanosheet composites (Ni‐UMOF/g‐C3N4 and Ni‐UMOF/GO) are obtained by a simple sol‐gel method and exhibit higher hydrogenation activity and recyclability than commercial Pd/C or Pt/C catalysts. The structures and properties of the catalysts are elucidated by X‐ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), atomic force microscope (AFM), fourier transform infrared spectra (FT‐IR), Raman, ultraviolet–visible spectroscopy (UV‐Vis), X‐ray photoelectron spectroscopy (XPS), electron spin‐resonance spectroscopy (ESR) and temperature‐programmed reduction (TPR). The results reveal that oxygen vacancies are produced on the surface of Ni‐UMOF composites and act as the dominating active sites during hydrogenation process. This sol‐gel method can be applied to synthesize other 2D ultrathin MOFs composites with high catalytic activities and recyclability for redox reactions.
A series of heterometallic Ni II /Co II coordination polymers with 2D networks were synthesized by tetrazole-1-acetate ligands and structurally characterized. With increasing concentration of cobalt(II), 1062another different connectivity patterns have been observed. The influence of cobalt(II) is not only on the crystallization, but also on the variation of magnetic properties. Scheme 1. Coordination modes of tetrazole-1-acetate ligand. Synthesis ofCompound 4: The ratio of Ni(OAc) 2 ·4H 2 O/CoCl 2 ·6H 2 O was used: 0.49 mmol/ 0.21 mmol. FT-IR (KBr): ν = 3476, 3131, 3002, cm -1 . ICP-AES: for the ratio of Ni : Co = 0.70:0.30. Synthesis of Compound 5: The ratio of Ni(OAc) 2 ·4H 2 O/CoCl 2 ·6H 2 O was used: 0.42 mmol/ 0.28 mmol. cm -1 . ICP-AES for the ratio of Ni : Co = 0.62:0.38. Synthesis of Compound 6: The ratio of Ni(OAc) 2 ·4H 2 O/CoCl 2 ·6H 2 O was used: 0.35 mmol/0.35 mmol. cm -1 . ICP-AES for the ratio of Ni : Co = 0.52:0.48. Synthesis of Compound 7: The ratio of Ni(OAc) 2 ·4H 2 O/CoCl 2 ·6H 2 O was used: 0.28 mmol/0.42 mmol. FT-IR (KBr): ν = 3458, 3137, 3004, , 580 cm -1 . ICP-AES for the ratio of Ni : Co = 0.44:0.56. Supporting Information (see footnote on the first page of this article): XRPD patterns of complexes with different ratio of Ni:Co and additional magnetic data for complexes 1-7.
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