Solution Synthesis of NdTe Magnetic Nanosheets.

Neodymium tritelluride is a layered van der Waals material, with correlated electronic properties including high electronic mobility, charge density waves, and antiferromagnetism. We developed a solution synthesis method to form free-standing nanosheets of NdTe, with nanosheet lateral dimensions of 200-400 nm. The morphology of the nanosheet was influenced by the neodymium precursor.

Low-Temperature Synthesis of Magnetic Pyrochlores (RMnO, R = Y, Ho-Lu) at Ambient Pressure and Potential for High-Entropy Oxide Synthesis.

Rare-earth manganese pyrochlores (RMnO) are frustrated magnetic materials, which previously have only been accessed using expensive high-pressure and high-temperature synthesis. In the present work, we demonstrate a convenient synthetic approach to synthesize RMnO pyrochlores at ambient pressure. A series of pyrochlores (R = Y, Ho-Lu) were prepared by a simple and cost-effective molten salt method using NaCl and KCl as the flux.

Molecular Parameters Promoting High Relaxivity in Cluster-Nanocarrier Magnetic Resonance Imaging Contrast Agents.

We have investigated the mechanism of relaxivity for two magnetic resonance imaging contrast agents that both employ a cluster-nanocarrier design. The first system termed MnFe-coPS comprises the cluster MnFeO(L)(HO) or MnFe () (L = carboxylate) co-polymerized with polystyrene to form ∼75 nm nanobeads. The second system termed MnBpy-PAm used the cluster Mn(OCCH)(Bpy) or MnBpy () where Bpy = 2,2'-bipyridine, entrapped in ∼180 nm polyacrylamide nanobeads.

Lanthanide Luminescence and Thermochromic Emission from Soft-Atom Donor Dichalcogenoimidodiphosphinate Ligands.

The luminescence properties of two divalent europium complexes of the type Eu[N(SPPh)](THF) () and Eu[N(SePPh)](THF) () were investigated. The first complex, Eu[N(SPPh)](THF) (), was found to be isomorphous with the reported structure of complex and exhibited room temperature luminescence with thermochromic emission upon cooling. We found the complex Eu[N(SePPh)](THF) () was also thermochromic but the emission intensity was sensitive to temperature.

The Accessibility of the Cell Wall in Scots Pine ( L.) Sapwood to Colloidal FeO Nanoparticles.

This work presents a rapid and facile way to access the cell wall of wood with magnetic nanoparticles (NPs), providing insights into a method of wood modification to prepare hybrid bio-based functional materials. Diffusion-driven infiltration into Scots pine ( L.) sapwood was achieved using colloidal FeO nanoparticles.

Synthesis of Mixed-Valent Lanthanide Sulfide Nanoparticles.

In targeting reduced valent lanthanide chalcogenides, we report the first nanoparticle synthesis of the mixed-valent ferromagnets Eu S and EuSm S . Using divalent lanthanide halides with bis(trimethylsilyl)sulfide and oleylamine, we prepared nanoparticles of EuS, Eu S , EuSm S , SmS , and Sm S . All nanoparticle phases were identified using powder X-ray diffraction, transmission electron microscopy was used to confirm morphology and nanoparticle size, and magnetic susceptibility measurements for determining the ordering temperatures and valence.

Paramagnetic MnFe--Polystyrene Nanobeads as a Potential T-T Multimodal Magnetic Resonance Imaging Contrast Agent with Studies.

In developing a cluster-nanocarrier design, as a magnetic resonance imaging contrast agent, we have investigated the enhanced relaxivity of a manganese and iron-oxo cluster grafted within a porous polystyrene nanobead with increased relaxivity due to a higher surface area. The synthesis of the cluster-nanocarrier for the cluster MnFeO(OCCHCH═CH)(HO), cross-linked with polystyrene (the nanocarrier), under miniemulsion conditions is described. By including a branched hydrophobe, -octane, the resulting nanobeads are porous and ∼70 nm in diameter.

Dissolution-Precipitation Synthesis and Characterization of Zinc Whitlockite with Variable Metal Content.

In the present work, a series of zinc whitlockite (CaZn(HPO)(PO)) powders was synthesized by a low-temperature dissolution-precipitation process for the first time. The phase conversion from calcium hydroxyapatite to zinc whitlockite occurred in an acidic medium in the presence of Zn ions. Variable chemical composition of the synthesis products was achieved by changing Ca-to-Zn molar ratio in the reaction mixture.

Giant band splittings in EuS and EuSe magnetic semiconductor nanocrystals.

Using magnetic circular dichroism (MCD) spectroscopy, we demonstrate giant temperature- and field-dependent conduction-band splittings in colloidal EuS and EuSe nanocrystals.

Mononuclear to Polynuclear U Structural Units: Effects of Reaction Conditions on U-Furoate Phase Formation.

Uranium(IV) complexation by 2-furoic acid (2-FA) was examined to better understand the effects of ligand identity and reaction conditions on species formation and stability. Five compounds were isolated: [UCl (2-FA) (H O) ] (1), [U Cl O (THF) (2-FA) ]⋅2 THF (2), [U O (OH) (H O) (2-FA) ]⋅7 THF⋅H O (3), [U O (OH) (H O) (2-FA) ]⋅8.76 H O (4), and [U Cl O (OH) (H O) ]⋅m H O⋅n THF (5).

Paramagnetic Clusters of Mn(OCCH)(Bpy) in Polyacrylamide Nanobeads as a New Design Approach to a T- T Multimodal Magnetic Resonance Imaging Contrast Agent.

There is an increasing need for gadolinium-free magnetic resonance imaging (MRI) contrast agents, particularly for patients suffering from chronic kidney disease. Using a cluster-nanocarrier combination, we have identified a novel approach to the design of biomedical nanomaterials and report here the criteria for the cluster and the nanocarrier and the advantages of this combination. We have investigated the relaxivity of the following manganese oxo clusters: the parent cluster Mn(OCCH)(Bpy) (1) where Bpy = 2,2'-bipyridine and three new analogs, Mn(OCCHCH═CH)(Bpy) (2), Mn(OCC(CH)═CH)(Bpy) (3), and MnO(OCCH)(Pyr) (4) where Pyr = pyridine.

Magnetic nanobeads as potential contrast agents for magnetic resonance imaging.

Metal-oxo clusters have been used as building blocks to form hybrid nanomaterials and evaluated as potential MRI contrast agents. We have synthesized a biocompatible copolymer based on a water stable, nontoxic, mixed-metal-oxo cluster, Mn8Fe4O12(L)16(H2O)4, where L is acetate or vinyl benzoic acid, and styrene. The cluster alone was screened by NMR for relaxivity and was found to be a promising T2 contrast agent, with r1 = 2.

Determination of the surface coverage of adsorbed dextran and beta-cyclodextrin derivatives on gold by surface titration.

The self-assembly of thiophene-containing dextran and cyclodextrin derivatives on gold surfaces was investigated. Morphological studies (AFM) and the elemental characterization (XPS) of the surfaces show that the carbohydrate derivatives form either aggregates or uniform films depending on the structure and the solvent used. The real coverage of the surface, and hence the amount of unmodified free gold, was examined by a "titration" of the surface with a carboxyl-terminated SAM (11-mercaptoundecanoic acid, MUA) and with Mn-12, a manganese oxocluster.

Luminescence of LnIII dithiocarbamate complexes (Ln = La, Pr, Sm, Eu, Gd, Tb, Dy).

We have discovered room temperature photoluminescence in Sm3+ and Pr3+ dithiocarbamate complexes. Surprisingly, these complexes exhibit more intense emission than those of the Eu3+, Tb3+, and Dy3+ analogues. The electronic absorption, excitation, and emission spectra are reported for the complexes [Ln(S2CNR2)3L] and NH2Et2[Ln(S2CNEt2)4], where Ln = Sm, Pr; R = ethyl, ibutyl, benzyl; and L = 1,10-phenanthroline, 2,2'-bipyridine, and 5-chloro-1,10-phenanthroline.

Magnetic properties of lanthanide chalcogenide semiconducting nanoparticles.

To understand the importance of the band gap to the magnetic ordering in magnetic semiconductors, we have studied the effect of particle size on the ferromagnetic Curie temperature in semiconducting EuS. We have synthesized capped approximately 20 nm EuS nanoparticles using a single-source precursor, [Eu(S(2)CN(i)()Bu(2))(3)Phen] decomposed in trioctylphosphine. The nanoparticles have been characterized by X-ray powder diffraction, TEM, and magnetic susceptibility measurements as a function of temperature and field.

Copper K-Edge X-ray Absorption Studies of La(2)(-)(x)()K(x)()CuO(4) Superconductors, Ba(4)NaCuO(4)(CO(3))(2), and NdCu(2)O(4).

X-ray near-edge absorption spectroscopy (XANES) measurements are reported at the Cu K-edge for La(2)(-)(x)()K(x)()CuO(4) superconductors with x = 0.1 and 0.2.