Results 1 - 6 of 6
Results 1 - 6 of 6. Search took: 0.015 seconds
|Sort by: date | relevance|
[en] This report describes affinity measurements for two, water-soluble, methyl-alkylated diamides incorporating the malonamide functionality, N,N,N?,N? tetramethylmalonamide (TMMA) and a bicyclic diamide (1a), towards actinide metal cations (An) in acidic nitrate solutions. Ligand complexation to actinides possessing oxidation states ranging from +3 to +6 was monitored through optical absorbance spectroscopy, and formation constants were obtained from the refinement of the spectrophotometric titration data sets. Species analysis gives evidence for the formation of 1, 4, 1, and 2 spectrophotometrically observable complexes by TMMA to An(III, IV, V, and VI), respectively, while for 1a, the respective numbers are 3, 4, 2, and 2. Consistent with the preorganization of 1a towards actinide binding, a significant difference is found in the magnitudes of their respective formation constants at each complexation step. It has been found that the binding affinity for TMMA follows the well established order: An(V)< An(III)< An(VI)< An(IV). However, with 1a, Np(V) forms stronger complexes than Am(III). The complexation of 1a with Np(V) and Pu(VI) at an acidity of 1.0 M is followed by reduction to Np(IV) and Pu(IV), whereas TMMA does not perturb the initial oxidation state for these dioxocations. These measurements of diamide binding affinity mark the first time single-component optical absorbance spectra have been reported for a span of actinide-diamide complexes covering all common oxidation states in aqueous solution
[en] A new bicyclic diamide compound, 3,9-diaza-3,9-dioctylbicyclo[4.4.0]decane-2,10-dione (1) has been prepared, and its affinity for Eu3+ and Am3+ has been explored using liquid-liquid extraction methods. Molecular mechanics calculations have shown that the two amide oxygen atoms in 1 should be ideally situated for binding to trivalent actinide or lanthanide ions and should form strong complexes. The data in this report support this hypothesis. As determined by liquid-liquid extraction, the affinity of 1 for Eu3+ is on the order of 107 times greater than previously investigated malonamides. The extraction behavior for Am3+ is similar to that of Eu3+
[en] Tin-doped indium oxide (ITO) nanoparticles are useful precursors to transparent electrodes in a variety of technologically important applications. We synthesized ITO nanoparticles from indium and tin acetylacetonates in oleyl alcohol using a novel temperature ramp profile. The monodispersed ITO nanoparticles have an average diameter of 8.6 nm and form dense, flat films by simple spin coating. The thickness of the film can be controlled by varying the number of additional depositions. The resulting ITO film is transparent and has a resistivity of 7 × 10−3 Ω cm after sintering at 300 °C. Using a suitable solvent, it is possible to coat high-aspect-ratio structures with ITO nanoparticles. This approach to ITO coatings is greener and offers a number of advantages for transparent electrodes because it is highly versatile, easily scalable, and supports low-cost manufacturing.
[en] A critical barrier to the routine use of nanomaterials is the tedious, expensive means of their synthesis. Microreaction technology takes advantage of the large surface area-to-volume ratios within microchannel structures to accelerate heat and mass transport. This accelerated transport allows for rapid changes in reaction temperatures and concentrations leading to more uniform heating and mixing which can have dramatic impacts on macromolecular yields and nanoparticle size distributions. Benefits of microreaction technology include higher yield and reactant conversion, better energy efficiency and less by-product generation. Microreactors can help minimize the environmental impact of nanoproduction by enabling solvent free mixing, integrated separation techniques and reagent recycling. The possibility of synthesizing nanomaterials in the required volumes at the point-of-use eliminates the need to store and transport potentially hazardous materials and provides the flexibility for tailoring complex functional nanomaterials. Recognizing these benefits for nanosynthesis, continuous flow microreactors have been used by several research groups to synthesize and characterize nanomaterials. An overview of these efforts and issues related to scale up and other post synthesis processes such as separation and deposition are presented in this paper.
[en] The quantity of information on nanomaterial properties and behavior continues to grow rapidly. Without a concerted effort to collect, organize and mine disparate information coming out of current research efforts, the value and effective use of this information will be limited at best. Data will not be translated to knowledge. At worst, erroneous conclusions will be drawn and future research may be misdirected. Nanoinformatics can be a powerful approach to enhance the value of global information in nanoscience and nanotechnology. Much progress has been made through grassroots efforts in nanoinformatics resulting in a multitude of resources and tools for nanoscience researchers. In 2012, the nanoinformatics community believed it was important to critically evaluate and refine currently available nanoinformatics approaches in order to best inform the science and support the future of predictive nanotechnology. The Greener Nano 2012: Nanoinformatics Tools and Resources Workshop brought together informatics groups with materials scientists active in nanoscience research to evaluate and reflect on the tools and resources that have recently emerged in support of predictive nanotechnology. The workshop goals were to establish a better understanding of current nanoinformatics approaches and to clearly define immediate and projected informatics infrastructure needs of the nanotechnology community. The theme of nanotechnology environmental health and safety (nanoEHS) was used to provide real-world, concrete examples on how informatics can be utilized to advance our knowledge and guide nanoscience. The benefit here is that the same properties that impact the performance of products could also be the properties that inform EHS. From a decision management standpoint, the dual use of such data should be considered a priority. Key outcomes include a proposed collaborative framework for data collection, data sharing and information integration. (paper)