Rare-Earth-Free Magnets: Enhancing Magnetic Anisotropy and Spin Exchange Toward High- HfIrB ( = Mn, Fe).

Designing new rare-earth-free (REF) permanent magnetic materials (PMM) to replace the high performing but critically restrained rare-earth-based PMM remains a great challenge to the scientific community. Here, we report on the rational design of new REF PMM, HfIrB ( = Fe, Mn) via a theory-experiment combined approach. Density functional theory (DFT) predicted strong interchain - spin-exchange coupling and large magnetocrystalline anisotropy energies () for the new compounds, suggesting potential intrinsic PMM properties.

A Delicate Balance between Antiferromagnetism and Ferromagnetism: Theoretical and Experimental Studies of A MRu B (A=Zr, Hf; M=Fe, Mn) Metal Borides.

Metal-rich borides with the Ti Co B -type structure represent an ideal playground for tuning magnetic interactions through chemical substitutions. In this work, density functional theory (DFT) and experimental studies of Ru-rich quaternary borides with the general composition A MRu B (A=Zr, Hf, M=Fe, Mn) are presented. Total energy calculations show that the phases Zr FeRu B and Hf FeRu B prefer ground states with strong antiferromagnetic (AFM) interactions between ferromagnetic (FM) M-chains.

High-Current-Density HER Electrocatalysts: Graphene-like Boron Layer and Tungsten as Key Ingredients in Metal Diborides.

Transition-metal borides belong to a small class of non-noble-metal electrocatalysts that exhibit excellent activity toward the hydrogen evolution reaction (HER) already in bulk form; those containing graphene-like (flat) boron layers, such as α-MoB , are particularly promising. In this study, the first tungsten-based boride HER electrocatalysts were studied experimentally and theoretically. Tungsten, the diborides of which (α- and β-WB ) contain both the active graphene-like (flat) boron layer and the less active phosphorene-like (puckered) boron layer, could be successfully substituted (up to 30 at %) for molybdenum in α-MoB .

Effect of Substitution on the Hysteretic Phase Transition in a Bistable Phenalenyl-Based Neutral Radical Molecular Conductor.

The ability to tune the physical properties of bistable organic functional materials by means of chemistry can facilitate their development for molecular electronic switching components. The butylamine-containing biphenalenyl boron neutral radical, [Bu] B, crystalline compound has recently attracted significant attention by displaying a hysteretic phase transition accompanied by simultaneous bistability in magnetic, electrical, and optical properties close to room temperature. In this report, substitutional doping was applied to [Bu] B by crystallizing solid solutions of bistable [Bu] B and its non-radical-containing counterpart [Bu] Be.

Unexpected Competition between Antiferromagnetic and Ferromagnetic States in HfMnRuB: Predicted and Realized.

Materials "design" is increasingly gaining importance in the solid-state materials community in general and in the field of magnetic materials in particular. Density functional theory (DFT) predicted the competition between ferromagnetic (FM) and antiferromagnetic (AFM) ground states in a ruthenium-rich TiCoB-type boride (HfMnRuB) for the first time. Vienna ab initio simulation package (VASP) total energy calculations indicated that the FM model was marginally more stable than one of the AFM models (AFM1), indicating very weak interactions between magnetic 1D Mn chains that can be easily perturbated by external means (magnetic field or composition).

Chemical Tuning of Magnetic Properties through Ru/Rh Substitution in ThFe-type FeRhRuB (n = 1-5) Series.

The new quaternary boride series FeRhRuB (n = 1-5) was synthesized by arc melting and characterized by powder and single-crystal X-ray diffraction (XRD), energy-dispersive X-ray analysis, and superconducting quantum interference device magnetometry. Single-crystal structure refinement showed the distribution of the iron atoms in two of three possible crystallographic 4d metal sites in the structure (ThFe-type, space group P6mc). Rietveld refinements of the powder XRD data indicated single-phase synthesis of all the members.

Supraicosahedral polyhedra in metallaboranes: synthesis and structural characterization of 12-, 15-, and 16-vertex rhodaboranes.

Syntheses and structural characterization of supraicosahedral rhodaborane clusters are reported. Reaction of [(Cp*RhCl2)2], (Cp* = η(5)-C5Me5) with [LiBH4·thf] followed by thermolysis with excess of [BH3·thf] afforded 16-vertex closo-[(Cp*Rh)3B12H12Rh{Cp*RhB4H9}], 1, 15-vertex [(Cp*Rh)2B13H13], 2, 12-vertex [(Cp*Rh)2B10Hn(OH)m], (3a: n = 12, m = 0; 3b: n = 9, m = 1; 3c: n = 8, m = 2) and 10-vertex [(Cp*Rh)3B7H7], 4, and [(Cp*Rh)4B6H6], 5. Cluster 1 is the unprecedented 16-vertex cluster, consists of a sixteen-vertex {Rh4B12} with an exo-polyhedral {RhB4} moiety.

Syntheses and characterization of new vinyl-borylene complexes by the hydroboration of alkynes with [(μ3-BH)(Cp*RuCO)2(μ-CO)Fe(CO)3].

Room temperature photolysis of a triply-bridged borylene complex, [(μ(3)-BH)(Cp*RuCO)(2)(μ-CO)Fe(CO)(3)] (1 a; Cp* = C(5)Me(5)), in the presence of a series of alkynes, 1,2-diphenylethyne, 1-phenyl-1-propyne, and 2-butyne led to the isolation of unprecedented vinyl-borylene complexes (Z)-[(Cp*RuCO)(2)(μ-CO)B(CR)(CHR')] (2: R, R' = Ph; 3: R = Me, R' = Ph; 4: R, R' = Me). This reaction permits a hydroboration of alkyne through an anti-Markovnikov addition. In stark contrast, in the presence of phenylacetylene, a metallacarborane, closo-[1,2-(Cp*Ru)(2)(μ-CO)(2){Fe(2)(CO)(5)}-4-Ph-4,5-C(2)BH(2)] (5 a), is formed.