From a historic point of view adenine was always presumed to be the product of HCN pentamerization. In this work a new mechanism for adenine synthesis in the gas phase without HCN is proposed. The concept of retrosynthetic analysis was employed to create a tautomer of adenine, which can be reached from previously observed interstellar molecules C3NH and HNCNH and its isomer H2NCN. MP2/6-311++G(2d,2p) calculations were performed to calculate the Gibbs free energy of the minimum and the transition state (TS) structures involved in the six step mechanism. This new mechanism requires a smaller number of steps, the reaction energy is twice as exergonic, and the rate determining TS is lower in energy than the corresponding ones proposed elsewhere in the literature.

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This work presents a theoretical study on the geometries and intramolecular energy transfer (IET) process of Tb3+‐complexes based on the Ruhemman's purple (RP) as ligands. Density functional theory and its time‐dependent extension are performed to examine the coordination energies and excited states using the ωB97X‐D3/MWB54/def2‐TZVP/polarizable continuum model level of theory. The inclusion of solvent effect causes a blueshift in all excitation energies, which is crucial for a better description of the electronic situations of RP isomers and coordination compounds. The IET rates are assessed for 18 Tb‐RP different compounds, each one with 44 IET pathways, also, it is obtained that the main energy transfer channel comes from the singlet state, in complete agreement with previous experimental data. The energy transfer from the singlet state is mainly composed of the nonradiative absorptions 7F6→5G6 and 7F5→5G5, representing together 97% of the total IET rate. As far as it is known, this is the first time that the solvent effect is included in the IET rates calculation, registering a step toward the development of IET analysis without any experimental or phenomenological input data.

A hydrothermal (HTMW) microwave method was used to synthesize ordered-disordered BaZrO 3 (BZ) nanoparticles at temperature of 140°C with times ranging from 15 min to 2 h. X-ray diffraction results verified the formation of BZ crystallites at a soaking time of 2 h while infrared data showed no traces of carbonate. Field emission scanning microcopy revealed a homogeneous size distribution of nanometric BZ powders. HTMW produced nanoparticles of pure BZ phase, with a size ranging from 40 to 80 nm. These results are in agreement with Raman scattering values which show that the HTMW synthesis route is rapid and cost effective. This method could be used as an alternative to obtain BZ nanoparticles as compared to other chemical methods. Intense photoluminescence in disordered BZ powders was observed at room temperature. The key of mystery of the intense PL emission is related to order-disorder structural in BZ lattice.

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