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Taking advantage of a pH-dependent solubility equilibrium, we have developed an aqueous synthesis of chemically and colloidally stable bismuth(0) glyconanoparticles. The synthetic method results in potentially biocompatible elemental bismuth nanoparticles (BiNPs) and involves the reduction of aqueous bismuth(III) cations by sodium borohydride in a pH-controlled solution. Medical-grade dextran (75 000 MW) was found to protect the nanocrystals from oxidation, in addition to promoting colloidal stability and separation of individual nanocrystallites. The rate of particle formation was dependent on synthesis pH, and decreasing the reaction rate by increasing the pH produced a greater number of individual and isolated Bi(0) nanocrystals. Stable, aqueous colloids of the dextran-coated BiNPs decomposed under prolonged light exposure, and the NPs dissolved both in acidic solutions (pH 12), but were stable in phosphate buffered saline solution (pH 7.4) and in other aqueous so...

We have developed a versatile, one-step melt synthesis of water-soluble, highly emissive silicon nanoparticles using bi-functional, low-melting solids (such as glutaric acid) as reaction media. Characterization through transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy shows that the one-step melt synthesis produces nanoscale Si cores surrounded by a silicon oxide shell. Analysis of the nanoparticle surface using FT-IR, zeta potential, and gel electrophoresis indicates that the bi-functional ligand used in the one-step synthesis is grafted onto the nanoparticle, which allows for tuning of the particle surface charge, solubility, and functionality. Photoluminescence spectra of the as-prepared glutaric acid-synthesized silicon nanoparticles show an intense blue-green emission with a short (ns) lifetime suitable for biological imaging. These nanoparticles are found to be stable in biological media and have been used to examine cellular uptake and distribution in live N2a cells.

Single crystals of EuGa2Pn2 (Pn = P, As) were grown from a molten Ga flux and characterized by single-crystal X-ray diffraction at 100(1) K. They are isostructural and crystallize in a new structure type (monoclinic, P2/m, a = 9.2822(9) A, b = 3.8967(4) A, c = 12.0777(11) A, β = 95.5220(10)°, R1 = 0.0148, wR2 = 0.0325 (EuGa2P2) and a = 9.4953(7) A, b = 4.0294(3) A, c = 12.4237(9) A, β = 95.3040(10)°, R1 = 0.0155, wR2 = 0.0315 (EuGa2As2)). The structures consist of alternating layers of two-dimensional Ga2Pn2 anions and Eu cations. The anion layers are composed of Ga2Pn6 staggered, ethane-like moieties having a rare Ga−Ga bonding motif; these moieties are connected in a complex fashion by means of shared Pn atoms. Both structures show small residual electron densities that can be modeled by adding a Eu atom and removing two bonded Ga atoms, resulting in structures (