Lithium manganese oxide, LiMn 2 O 4 , was synthesized in two temperature stages, where the first consisted by an ecofriendly solution combustion method at 300 °C. Finally, the as-burned powders were thermal treated at 500 and 700 °C. The structural and morphological changes were evaluated by the Rietveld method and density functional theory (DFT) calculations. The Rietveld refinement indicates obtaining the spinel cubic phase LiMn 2 O 4 and a small amount of Mn 2 O 3 . The analyses by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show a porous microstructure composed of nano-sized crystallites for the sample treated at 500 °C. In cyclic voltammetry, it was possible to observe that the reduction-oxidation reaction is reversible due to the shape of voltammograms and the anodic and cathodic peaks of Mn ions. The theoretical calculations considered the experimental crystallographic parameters. The unit cell volume change was evaluated according to distinct amounts of lithium ions in the structure. The removal of the Li + cations from the oxides promotes a volume contraction. Therefore, it was possible to evaluate the participation of the Mn 3+ ions in the frontier region between the valence and conduction bands. The density of states (DOS) calculation shows a predominant contribution of the O 2p and Mn 3d orbitals in the frontier orbitals.

In the pharmaceutical area, some drugs exhibit physicochemical properties that adversely affect the formulation processes to bioavailability and its effectiveness. Nevirapine (NVP) is an antiretroviral drug that presents low aqueous solubility, which impacts directly in its bioavailability. Among all possible modifications, multicomponent crystals, such as cocrystals and eutectic compositions, have been successfully used to improve the solubility of drugs. In this work, the propensity of the formation of multicomponent systems of NVP with seven possible co-formers were predicted and tested: salicylic acid (SA), 3-hydroxybenzoic acid (3HBZC), 4hydroxybenzoic acid (4HBZC), saccharin (SAC), theophylline (THEO), caffeine (CAF), and urea (URE). Results indicate that NVP-SA, NVP-SAC, NVP-3HBZC, and NVP-4HBZC are cocrystals, whereas NVP-THEO and NVP-CAF are eutectic materials, and NVP-URE is a solid physical mixture. A temperature-dependent disorder behavior was identified for NVP-SA cocrystal. Dissolution studies for the eutectic materials are reported, evidencing that these materials exhibit a significant increase in NVP dissolution kinetics.

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The chemical composition, [Mg0.015 (2),Al1.20 (2),Si2.99 (1),Ca3.00 (2),Ti0.027 (3),Mn0.017 (3), Fe0.75 (3)]O12 (magnesium alumin­ium silicon calcium titanium manganese iron dodeca­oxide), of a natural garnet collected at Diamantina, Minas Gerais, Brazil was determined by electron microprobe analysis. The structure refinement from X‐ray powder data is insensitive to the small amounts of Ti, Mn and Mg. The determined cation distribution using the Rietveld method is {Ca32+}[Al1.338 (8)3+,Fe0.662 (8)3+](Si34+)O122−, which is in agreement with a solid solution of the grossular‐andradite series. The arrangement of the cations around the O atom is best described as a highly distorted tetrahedral.

Chagas disease is a neglected tropical disease caused by the protozoan pathogen Trypanosoma cruzi. The disease is the major public health problem affecting about 6 to 7 million people worldwide,...

This paper reports the synthesis, structures, and photophysical and electroluminescence properties of low symmetry NIR emitting octa- and nona-coordinate Nd tris β-diketonate complexes.

In this work a microwave-assisted Knoevenagel/Michael/cyclization multicomponent domino methodology, using ethanol as solvent and the ionic liquid 1-methylimidazolium chloride as catalyst was developed for the synthesis of spiro compounds. The reaction conditions considered ideal were determined from a methodological study varying solvent, catalyst, amount of catalyst, temperature, and heating mode. Finally, the generality of the methodology was evaluated by exploring the scope of the reaction, varying the starting materials (isatin, malononitrile, and barbituric acid). Overall, the twelve spiro compounds were synthesized in good yields (43–98%) and the X-ray structure of compound 1b was obtained. In addition, the in vitro antiproliferative activities of the spirocycles against four types of human cancer cell lines including HCT116 (human colon carcinoma), PC3 (prostate carcinoma), HL60 (promyelocytic leukemia), and SNB19 (astrocytoma) were screened by MTT-based assay. It is noteworthy that spiro compound 1c inhibited the four cell lines tested with the lowest IC50 values: 52.81 µM for HCT116, 74.40 µM for PC3, 101 µM for SNB19, and 49.72 µM for HL60.

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