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The functionalization of graphene oxide with organosilanes is an important strategy to yield graphene-silica composites as well as to create nanomaterials for use as reinforcement in polymer nanocomposites and corrosion-inhibiting coatings for metals, among other uses. However, depending on the reaction conditions used, the organosilanes tend to self-condense, encapsulating the graphene oxide in a silica-like layer which can impair its properties by hiding its real surface and two-dimensionality. In this paper we describe a facile route for the functionalization of commercial graphene oxide with (3-aminopropyl) triethoxysilane using low concentrations and mild reaction conditions, and yielding amine and silanol surface-modified graphene nanohybrids while preserving its two-dimensional characteristics. The material obtained was characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), potentiometric titration, thermogravimetric analysis and electronic microscopy, evidencing the covalent and superficial nature of the functionalization.

Reactions of SnBu 3 Cl, TiCl 4 and NH 4 OH in ethanol followed by pyrolysis of the resultant product at 550• C, either in an atmosphere of oxygen or hydrogen, yielding new SnO 2 -TiO 2 based composites. In all, eight products were prepared with weight ratios of Sn-TiO 2 of 0% (1), 5% (2), 15% (3) and 30% (4) in O 2 and 0% (5), 5% (6), 15% (7) and 30% (8) in H 2 . XRD revealed diffraction patterns of TiO 2 (anatase) in the composites, but not those of SnO 2 due to its insufficient crystallinity. Scanning electron microscopy indicated the presence of Sn metal on the surface of composites 6-8. 119 Sn Mössbauer experiments revealed SnO 2 in all samples, and increasing amounts of tin in samples 7 and 8, respectively. The composites were used in experiments of photocatalytic degradation of indigo carmine dye. The catalytic experiments monitored by mass spectrometry and electronic spectroscopy revealed that, in the conditions of the experiments, composite 8 displays the highest activity. In addition, degradation products were characterised using electrospray ionization mass spectrometry (ESI-MS and ESI-MS/MS) data.

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Thalidomide was indicated as a sedative and antiemetic and prescribed for pregnant women. Its tragic teratogenic effects culminated in withdrawal from the market. Since the discovery of its anti-angiogenic and anti-inflammatory actions, thalidomide has been used in the treatment of leprosy and multiple myeloma, which justify studies of its stability. We investigated the effects of irradiation of thalidomide up to 100 kGy (fourfold the usual sterilizing dose for pharmaceutics). The β polymorph of thalidomide was obtained in an isothermal experiment at 270 °C. All samples underwent gamma irradiation for specific times. At different doses, decomposition of the pharmaceutical was not observed up to 100 kGy. The observed effect was angle turning between the phthalimide and glutarimide rings modulated by repulsion towards the carbonyl group, leading to a stable energetic configuration, as measured by the equilibrium in the torsion angle after irradiation. The thalidomide molecule has a center of symmetry, so a full turn starting from 57.3° will lead to an identical molecule. Further irradiation will start the process again. Samples irradiated at 30 and 100 kGy have more compact unit cells and a lower volume, which leads to an increase in the intermolecular hydrogen interaction within the unit cell, resulting in higher thermal stability for polymorph α.