The feasibility of high-resolution Lu solid-state NMR spectroscopy in intermetallic compounds crystallizing with cubic crystal structures is explored by magic-angle spinning NMR at different magnetic flux densities. The large quadrupole moment of this isotope (3.49 × 10 m) restricts observation of the NMR signal to nearly perfectly ordered crystalline samples. Signals are successfully detected and analyzed in the binary pnictides LuPn (NaCl-type structure; Pn = P, As, Sb) and the intermetallic compounds LuPtSb and LuAuSn, both crystallizing with the MgAgAs-type structure. Sources of line broadening are discussed based on field-dependent static and MAS-NMR spectra, providing guidance with respect to measurement conditions resulting in reliable results. The results highlight the importance of ionic/covalent bonding effects for the detectability of the signal, which reduce the probability of real structure effects commonly observed in intermetallic compounds. No Lu NMR signals can be observed in various cubic Heusler compounds. This is attributed to mixed site occupancies and other structural defects producing electric field gradients whose interaction with the Lu quadrupole moments broadens the signal beyond detection.
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http://dx.doi.org/10.1016/j.ssnmr.2019.05.003 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
State Key Laboratory of Fine Chemicals, Laboratory of Advanced Materials and Catalytic Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
The industrial advancement of downstream products resulting from the directed hydrogenation of maleic anhydride is hindered by the limitations related to the activity and stability of catalysts. The development of nonprecious metal intermetallic compounds, in which active sites are adjustable in the local structures and electronic properties embedded within a distinct framework, holds immense potential in enhancing catalytic efficacy and stability. Herein, we report that nickel-based silicides catalysts, RNiSi (R = Ca, La, and Y), afford high efficiency in the selective hydrogenation of maleic anhydride.
View Article and Find Full Text PDFChemistry
January 2025
The University of British Columbia, Department of Chemistry, 2036 Main Mall, V6T 1Z1, Vancouver, CANADA.
The field of platinum chemistry is ubiquitous in the research of anticancer drugs and new OLED materials. Within the vast library of existing compounds, the majority of work focuses on complexes in the +2 and +4 oxidation states, with comparatively few examples of PtIII complexes reported without bridging ligands. PtIII complexes with metal-metal bonding can be made by mild oxidation of PtII complexes having bis(phenylpyridine) ligands.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
College of Energy Engineering, Huanghuai University, Zhumadian 463000, China. Electronic address:
Herein, a novel liquid nitrogen quenching treatment is proposed to achieve multifaceted modulation involving morphological modulation, lattice tensile strain modulation, metal active centre coordination reconstruction and grain boundary construction within a series of intermetallic compounds modified on a carbon substrate (CoFe-550/C, CoNi-550/C and FeNi-550/C, where 550 refers to liquid nitrogen quenching temperature and C refers to the carbon substrate). Noteworthily, the optimising intermediate absorption/desorption process is achieved by multifaceted modulation. Consequently, CoFe-550/C, CoNi-550/C and FeNi-550/C demonstrate considerable overpotential for hydrogen evolution reaction (59.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Department of Applied Mechanics, FEMTO-ST Institute, CNRS, Université de Franche-Comté, 25000 Besançon, France.
Hydrogen storage in intermetallic compounds, known as solid-state storage, relies on a phase change by the metal alloy. This phenomenon causes a violent change in volume at the crystalline scale, inducing a change of volume for the millimetric particles and, with time, important stresses on the tanks. It is thus necessary to know the mechanical behavior of the material to report these phenomena and improve the tanks' reliability.
View Article and Find Full Text PDFIsostructural Dy(III) and Er(III) complexes [L12Ln(H2O)5][I]3·L12·(CH2Cl2) (Ln = Dy (1), Er (3)) and [L22Ln(H2O)5][I]3·L22·(CH2Cl2)2 (Ln = Dy (2), Er (4)), with distorted pentagonal bipyramidal geometry (D5h) around the central metal were synthesized by utilizing two bulky phosphonamide ligands, adamantyl phosphonamide, (Ad)P(O)(NHiPr)2 (L1) and carbazolyl phosphoramide (Cz)P(O)(NHiPr)2 (L2). The resultant complexes were investigated for their magnetic properties in order to elucidate the impact of modification of the coordinating P-O bond environment either by increasing steric bulk and/or introduction of a third P-N bond at the central phosphorus atom. Magnetic studies revealed substantial energy barriers (Ueff) of 640 K and 560 K for Dy compounds 1 and 2, respectively, rendering them as some of the best-performing air-stable SIMs amongst the class of SIMs with D5h symmetry.
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