Formation of radical anions after adsorption of 1,3,5-trinitrobenzene (TNB) on electron donor sites of fully oxidized Al₂O₃ samples with different phase compositions is studied by EPR. It is shown that the maximum concentration of the radical anions does not substantially depend on the choice of solvent and reaction temperature, and can be used to measure the total concentration of the donor sites. The donor sites are observed in almost the same concentration about 5 × 10¹⁶ m⁻² on all alumina polymorphs except for α-Al₂O₃. The formation rate of the TNB radical anions and the activation energy of this process are found to depend on the donor properties of the solvent. The EPRin situ experiments showed that a substantial amount of the adsorbate forming a liquid phase is required for generation of the radical anions. These results prove that the sites measured by the formation of the TNB radical anions are not genuine electron donor sites capable of direct electron transfer to the adsorbed TNB molecules. A model of the observed paramagnetic species based on the obtained experimental data and the results of quantum chemical simulations is suggested. According to this model, a TNB radical anion substitutes a hydroxyl group forming a neutral ion pair with a surface aluminum cation. The suggested mechanism for the formation of such ion pairs involves the migration of simple radicals and does not require long-distance charge separation. It is supposed that the donor site where the process is initiated includes a negatively charged surface hydroxyl group.

Carbon-coated MgO nanoparticles, with carbon forming a porous coating on the surface of MgO nanoparticles, have been prepared by two different techniques. Resorcinol has been found to be an efficient agent for the modification of magnesium methoxide leading to carbon-coated MgO nanocrystals of small crystallite size and high surface area. Decomposition of dry magnesium methoxide under an inert gas flow proved to be another efficient and economical way to synthesise carbon-coated MgO. The carbon coating acts as a hydrophobic barrier partially protecting the core metal oxide from water adsorption and conversion to magnesium hydroxide. However, destructive adsorption reactions can still proceed on the metal oxide surface, as evidenced by the dehydrochlorination of 2-chloroethyl ethyl sulfide (2-CEES) and 1-chlorobutane. The overall stability of the material in the presence of water vapor is significantly improved in comparison with non-coated nanocrystalline MgO.