Abstract: After an introduction to lithium insertion compounds and the principles of Li-ion cells, we present a comparative study of the physical and electrochemical properties of positive electrodes used in lithium-ion batteries (LIBs). Electrode materials include three different classes of lattices according to the dimensionality of the Li+ ion motion in them: olivine, layered transition-metal oxides and spinel frameworks. Their advantages and disadvantages are compared with emphasis on synthesis difficulties, electrochemical stability, faradaic performance and security issues.
Abstract: This review deals with the reactions of diarylplatinum(II) complexes with N-donor ligands to produce a variety of cycloplatinated compounds including endo-five-, endo-seven-, endo-six- or exo-five-membered platinacycles. The observed reactions result from a series of oxidative addition/reductive elimination processes taking place at platinum(II)/platinum(IV) species and involving C–X (X = H, Cl, Br) bond activation, arene elimination, and, in some cases, Caryl–Caryl bond formation.
Abstract: The continuous rising of the cancer patient death rate undoubtedly shows the pressure to find more potent and efficient drugs than those in clinical use. These agents only treat a narrow range of cancer conditions with limited success and are associated with serious side effects caused by the lack of selectivity. In this frame, innovative syntheses approaches can decisively contribute to the success of “smart compounds” that might be only selective and/or active towards the cancer cells, sparing the healthy ones. In this scope, ruthenium chemistry is a rising field for the search of proficient metallodrugs by the use of macromolecular ruthenium complexes (dendrimers and dendronized polymers, coordination-cage and protein conjugates, nanoparticles and polymer-“ruthenium-cyclopentadienyl” conjugates) that can take advantage of the singularities of tumor cells (vs. healthy cells).
Abstract: Systematic studies in the systems Cs–Na–Ga–Si, Rb–Na–Ga–Si, and Rb–Na–Zn–Si yielded the novel type-I clathrates with refined compositions Cs6Na2Ga8.25Si37.75(3), Rb6.34Na1.66(2)Ga8.02Si37.98(3), and Rb5.20Na2.80(4)Zn3.85Si42.15(2) (cubic, ), as well as the type-II clathrates with formulae Cs8Na16Ga22.7Si113.3(1), Rb8.4Na15.6(1)Ga19.6Si116.4(1), and Rb8Na16Zn8.4Si127.6(1) (cubic, ). In each system, the type-I and -II compounds are always co-crystallizing, irrespective of the reaction conditions. The structures derived from single-crystal X-ray diffraction confirm complete ordering of Cs and Na atoms, and nearly complete ordering of the Rb and Na guest atoms. The framework-building Si atoms are randomly substituted by Ga or Zn atoms on all framework sites with notable difference in the substitution patterns between the type-I and type-II structure. This, and other details of the crystal chemistry are discussed in this paper.
Abstract: Ammonothermal synthesis is a method for synthesis and crystal growth suitable for a large range of chemically different materials, such as nitrides (e.g., GaN, AlN), amides (e.g., LiNH2, Zn(NH2)2), imides (e.g., Th(NH)2), ammoniates (e.g., Ga(NH3)3F3, [Al(NH3)6]I3 · NH3) and non-nitrogen compounds like hydroxides, hydrogen sulfides and polychalcogenides (e.g., NaOH, LiHS, CaS, Cs2Te5). In particular, large scale production of high quality crystals is possible, due to comparatively simple scalability of the experimental set-up. The ammonothermal method is defined as employing a heterogeneous reaction in ammonia as one homogenous fluid close to or in supercritical state. Three types of milieus may be applied during ammonothermal synthesis: ammonobasic, ammononeutral or ammonoacidic, evoked by the used starting materials and mineralizers, strongly influencing the obtained products. There is little known about the dissolution and materials transport processes or the deposition mechanisms during ammonothermal crystal growth. However, the initial results indicate the possible nature of different intermediate species present in the respective milieus.
Abstract: In this paper we examine the effect of doping phosphate into BaCe1−yAyO3−y/2 (A = Y, Yb, In). The samples were analysed through a combination of X-ray diffraction, TGA, Raman spectroscopy and conductivity measurements. The results showed that phosphate could be incorporated into this system up to the 10% doping level, although this required an increased Y/Yb/In content, e.g., BaCe0.6(Y/In/Yb)0.3P0.1O2.9. The phosphate doping was, however, shown to lead to a decrease in conductivity; although at low phosphate levels high conductivities were still observed, e.g., for BaCe0.65Y0.3P0.05O2.875, σ = 4.3 × 10−3 S cm−1 at 600 °C in wet N2. In terms of the effect of phosphate incorporation on the CO2 stability, it was shown to lead to a small improvement for the In containing samples, whereas the yttrium doped compositions showed no change in CO2 stability.