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Abstract: The aim of this work is the study of the H2 release from the thermal decomposition reaction of sodium tetrahydroboride (NaBH4) in the solid state. Computational and experimental methods have been used. NaBH4 thermodynamic properties at room temperature and its energy of formation from NaH and BH3 have been theoretically studied using a first-principles approach. Results obtained from ab initio calculations compared well with thermodynamic properties assessed by the CALPHAD method. The effect of annealing on phase transformations in NaBH4 has been followed with various experimental analytical techniques and the structure of the samples, after suitable thermal treatments, has been analysed by X-ray diffraction. A multi-step reaction has been observed after annealing, in both isothermal and scanning conditions. The conditions for H2 release from NaBH4 in the solid state have been clarified combining experimental and computational results. [Copyright &y& Elsevier]

Abstract: In the present paper, a review of our previously published results about the ab initio modeling on the interaction with the polarizing centers of proton- and metal-exchanged chabazites performed with the periodic ab initio CRYSTAL code is reported. The paper highlights how ab initio modeling allows to: (i) understand the interaction with solids at an atomistic level; (ii) infer the potential of zeolites as hydrogen storage materials; (iii) give insights in the design of new storage materials for applications. The calculations were performed within the periodic approach using the B3LYP functional with all-electron double zeta polarized Gaussian type basis sets. New data are reported using a richer basis set for both zeolite and , which ensures a better description of the intermolecular interaction components. In all the considered systems, mainly interacts side-on with zeolites’ charge balancer cations. Geometrical and energetic features were also refined at MP2 level adopting clusters cut out from the chabazite framework in order to gauge the dispersive contribution to the interaction energy, not accounted for by the B3LYP functional. Computed BSSE-free binding energies showed that interacts poorly with the protons of the Brønsted sites , whereas the interaction with , and in metal-exchanged chabazites was stronger, particularly for located in small framework rings . When divalent cation is used as a charge balancer, the becomes , showing that the interplay between cationic polarization and its spatial position in the zeolite framework is crucial in determining the sorption capacity of the material. [Copyright &y& Elsevier]

Abstract: A coupled ab initio and thermodynamic study of the Al–H–Mg system has been carried out and a self-consistent thermodynamic database has been obtained. Magnesium alanate Mg(AlH4)2, a candidate material for hydrogen storage, has been included into the database. According to Density Functional first principles calculations, the alanate is an insulator and its thermodynamic properties have been obtained at room temperature. This compound has been found metastable at 298.15 K and 1 bar. The alanate has been found thermodynamically stable only at high pressure when the formation of the binary β-MgH2 phase is neglected. A reassessment of thermodynamic parameters of the liquid phase in the binary Mg–H system has also been carried out in order to be consistent with the Al–H system. The present results can reproduce reasonably well the available experimental data. [Copyright &y& Elsevier]

The NS2B-NS3 protease is essential for the Dengue Virus (DENV) replication process. This complex constitutes a target for efficient antiviral discovery because a drug could inhibit the viral polyprotein processing. Furthermore, since the protease is highly conserved between the four Dengue virus serotypes, it is probable that a drug would be equally effective against all of them. In this article, a strategy is reported that allowed us to identify influential residues on the function of the Dengue NS2b-NS3 Protease. Moreover, this is a strategy that could be applied to virtually any protein for the search of alternative influential residues, and for non-competitive inhibitor development. First, we incorporated several features derived from computational alanine scanning mutagenesis, sequence, structure conservation, and other structure-based characteristics. Second, these features were used as variables to obtain a multilayer perceptron model to identify defined groups (clusters) of key residues as possible candidate pockets for binding sites of new leads on the DENV protease. The identified residues included: i) amino acids close to the beta sheet-loop-beta sheet known to be important in its closed conformation for NS2b ii) residues close to the active site, iii) several residues evenly spread on the NS2b-NS3 contact surface, and iv) some inner residues most likely related to the overall stability of the protease. In addition, we found concordance on our list of residues with previously identified amino acids part of a highly conserved peptide studied for vaccine development. [ABSTRACT FROM AUTHOR]