Dual-Function Cobalt-Nickel Nanoparticles Tailored for High-Temperature Induction-Heated Steam Methane Reforming.

The tailored chemical synthesis of binary and ternary alloy nanoparticles with a uniform elemental composition is presented. Their dual use as magnetic susceptors for induction heating and catalytic agent for steam reforming of methane to produce hydrogen at temperatures near and above 800 °C is demonstrated. The heating and catalytic performance of two chemically synthesized samples of CoNi and Cu⊂CoNi are compared and held against a traditional Ni-based reforming catalyst. The structural, magnetic, and catalytic properties of the samples were characterized by X-ray diffraction, elemental analysis, magnetometry, and reactivity measurements. For induction-heated catalysts, the conversion rate of methane is limited by chemical reactivity, as opposed to the case of traditional externally heated reformers where heat transport limitations are the limiting factor. Catalyst production by the synthetic route allows controlled doping with miniscule concentrations of auxiliary metals.

[ReF(6)](2-) : a robust module for the design of molecule-based magnetic materials.

A facile synthesis of the [ReF6 ](2-) ion and its use as a building block to synthesize magnetic systems are reported. Using dc and ac magnetic susceptibility measurements, INS and EPR spectroscopies, the magnetic properties of the isolated [ReF6 ](2-) unit in (PPh4 )2 [ReF6 ]⋅2 H2 O (1) have been fully studied including the slow relaxation of the magnetization observed below ca. 4 K. This slow dynamic is preserved for the one-dimensional coordination polymer [Zn(viz)4 (ReF6 )]∞ (2, viz=1-vinylimidazole), demonstrating the irrelevance of low symmetry for such magnetization dynamics in systems with easy-plane-type anisotropy. The ability of fluoride to mediate significant exchange interactions is exemplified by the isostructural [Ni(viz)4 (ReF6 )]∞ (3) analogue in which the ferromagnetic Ni(II) -Re(IV) interaction (+10.8 cm(-1) ) dwarfs the coupling present in related cyanide-bridged systems. These results reveal [ReF6 ](2-) to be an unique new module for the design of molecule-based magnetic materials.

Molecular multifunctionality preservation upon surface deposition for a chiral single-molecule magnet.

The synthesis and characterization of a chiral, enneanuclear Mn(iii)-based, Single-Molecule Magnet, [Mn9O4(Me-sao)6(L)3(MeO)3(MeOH)3]Cl (1; Me-saoH2 = methylsalicylaldoxime, HL = lipoic acid) is reported. Compound 1 crystallizes in the orthorhombic P212121 space group and consists of a metallic skeleton describing a defect super-tetrahedron missing one vertex. The chirality of the [MnIII 9] core originates from the directional bridging of the Me-sao2- ligands via the -N-O- oximate moieties, which define a clockwise (1ΔΔ) or counter-clockwise (1ΛΛ) rotation in both the upper [MnIII 3] and lower [MnIII 6] subunits. Structural integrity and retention of chirality upon dissolution and upon deposition on (a) gold nanoparticles, 1@AuNPs, (b) transparent Au(111) surfaces, 1ΛΛ@t-Au(111); 1ΔΔ@t-Au(111), and (c) epitaxial Au(111) on mica surfaces, 1@e-Au(111), was confirmed by CD and IR spectroscopies, mass spectrometry, TEM, XPS, XAS, and AFM. Magnetic susceptibility and magnetization measurements demonstrate the simultaneous retention of SMM behaviour and optical activity, from the solid state, via dissolution, to the surface deposited species.

Imposing high-symmetry and tuneable geometry on lanthanide centres with chelating Pt and Pd metalloligands.

Exploitation of HSAB preferences allows for high-yield, one-pot syntheses of lanthanide complexes chelated by two Pd or Pt metalloligands, [MII(SAc)4]2- (SAc- = thioacetate, M = Pd, Pt). The resulting complexes with 8 oxygen donors surrounding the lanthanides can be isolated in crystallographically tetragonal environments as either [NEt4]+ (space group: P4/mcc) or [PPh4]+ (space group: P4/n) salts. In the case of M = Pt, the complete series of lanthanide complexes has been structurally characterized as the [NEt4]+ salts (except for Ln = Pm), while the [PPh4]+ salts have been structurally characterized for Ln = Gd-Er, Y. For M = Pd, selected lanthanide complexes have been structurally characterized as both salts. The only significant structural difference between salts of the two counter ions is the resulting twist angle connecting tetragonal prismatic and tetragonal anti-prismatic configurations, with the [PPh4]+ salts approaching ideal D4d symmetry very closely (φ = 44.52-44.61°) while the [NEt4]+ salts exhibit intermediate twist angles in the interval φ = 17.28-27.41°, the twist increasing as the complete 4f series is traversed. Static magnetic properties for the latter half of the lanthanide series are found to agree well in the high temperature limit with the expected Curie behavior. Perpendicular and parallel mode EPR spectroscopy on randomly oriented powder samples and single crystals of the Gd complexes with respectively Pd- and Pt-based metalloligands demonstrate the nature of the platinum metal to strongly affect the spectra. Consistent parametrization of all of the EPR spectra reveals the main difference to stem from a large difference in the magnitude of the leading axial term, B02, this being almost four times larger for the Pt-based complexes as compared to the Pd analogues, indicating a direct Pt(5d z2 )-Ln interaction and an arguable coordination number of 10 rather than 8. The parametrization of the EPR spectra also confirms that off-diagonal operators are associated with non-zero parameters for the [NEt4]+ salts, while only contributing minimally for the [PPh4]+ salts in which lanthanide coordination approximates D4d point group symmetry closely.