At the second order Douglas-Kroll-Hess (DKH2) level, the B3PW91 functional in conjunction with the relativistic all-electron basis set of valence triple zeta quality plus polarization functions are employed to compute bond lengths, dissociation energies, vertical ionization potentials, and the highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps of the small iridium clusters (Ir n , n 8). These results are compared with the experimental and theoretical data available in the literature. Our results confirm the theoretical predictions made by Feng et al. about the catalytic activities of the Ir 4 and Ir 6 clusters. From the optimized geometries, DKH2 calculations of static electric mean dipole polarizabilities and polarizability anisotropies are also carried out. It is the first time that the polarizabilities of small iridium clusters have been studied. For n 4, the mean dipole polarizabilities per atom present an odd-even oscillatory behavior, whereas from Ir 5 to Ir 8 , they decrease with the cluster size increasing. The dependence of the polarizability anisotropy on the structure symmetry of the iridium cluster is verified.

COVID-19 triggered by Sars-CoV-2 has caused hundreds of thousands of deaths worldwide. Organic and inorganic compounds have been tested as potential inhibitors of this lethal virus. For these tests, several techniques are use to design molecules of biological interest for drug composition, in which molecular coupling plays an important role. In the present work, the compounds acids kaurenoic, copalic, and beta-caryophyllene that form the copaiba oil were studied as anti-inflammatories and opens the possibility to inhibit Sars-CoV-2. Molecular docking showed alkyl, pi-alkyl, conventional H-bond, unfavorable bump, and Van der Waals interactions. The calculated electrostatic potential maps showed the nucleophilic and electrophilic regions. The negative binding energies obtained for the three acids suggest the stability of the complexes. The minimum energy states for β-caryophyllene are lower than the other compounds analyzed, and it can be predicted that this is the most stable.

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The use of markers of organic compounds by dansyl chloride (DNS-Cl) through fluorescence can be widely used in areas such as pharmacology, toxicology, organic synthesis, and biochemistry. The theoretical computational study of the molecular structure of DNS-Cl in crystalline form is not reported in the literature. In this work, we calculate the structural, electronic, optical, and vibrational properties. Using density functional theory, we consider general gradient approximation with dispersion correction (GGA+TS) and local density approximation (LDA-CAPZ). We hope that this work will be of great importance for the theoretical study of the crystal structure of DNS-Cl and serve as a database for future studies.