Examinando por Autor "Báez-Grez, Rodrigo"
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- PublicaciónSólo datosCarbon rings decorated with group 14 elements: new aromatic clusters containing planar tetracoordinate carbon(New Journal of Chemistry, 2019-04-03) Yañez, Osvaldo; Vásquez-Espinal, Alejandro; Báez-Grez, Rodrigo; Rabanal-León, Walter A.; Osorio, Edison; Ruiz, Lina; Tiznado, WilliamA simple and chemically intuitive approach is used to design ptC-containing E–C clusters (E = Si–Pb). This approach consists in replacing three or two consecutive protons from an aromatic hydrocarbon by one E24+ or one E2+ fragment, respectively. In the model, electrons from E are removed from the pz orbitals, emptying them. Si–Pb favors the formation of a 3c-2e (E–C–E) σ-bond, which involves the ptC. Additionally, the π-electronic cloud is delocalized through the E-pz orbitals allowing the E atoms to effectively take part in the electronic delocalization, preserving the 4n + 2 Hückel's rule from the parent hydrocarbon. Two aromatic monocycles and one aromatic bicycle – benzene (C6H6), cyclopentadienyl anion (C5H5−) and pentalene dianion (C8H62−) – have been transformed into C–E systems. After an extensive exploration of their potential energy surfaces, four new global minima with ptC are identified, resulting from the substitution of the protons by Si and Ge cations in C5H5− and C8H62− (E3C5 and E4C8). The analysis of both the chemical bonding and the magnetic response to an external magnetic field confirms the aromatic character of these species.
- PublicaciónSólo datosExploring the Potential Energy Surface of Trimetallic Deltahedral Zintl Ions: Lowest-Energy [Sn6Ge2Bi]3– and [(Sn6Ge2Bi)2]4– Structures(Inorganic Chemistry, 2019-07-09) Báez-Grez, Rodrigo; Garza, Jorge; Vásquez-Espinal, Alejandro; Osorio, Edison; Rabanal-León, Walter A.; Yañez, Osvaldo; Tiznado, WilliamThe synthesis and structural characterization of the dimer [(Sn6Ge2Bi)2]4– raise the possibility of obtaining a broad variety of analogous compounds with different Sn/Ge/Bi proportions. Several combinations of nine atoms have been detected by electrospray mass spectrometry as potential assembly units. However, [(Sn6Ge2Bi)2]4– remains as the unique experimentally characterized species in this series. This fact has motivated us to explore its potential energy surface, as well as its monomers’ [Sn6Ge2Bi]3–/2–, in an effort to gain insight into the factors that might be privileging the experimental viability of this species. Our results show that the lowest-energy [Sn6Ge2Bi]3– structure remains in its oxidized product [Sn6Ge2Bi]2–, which corresponds to that identified in the dimer [(Sn6Ge2Bi)2]4–. Additionally, local minima, very close in energy to the lowest-energy monomer, are chiral mixtures that dimerize into diverse structures with a probable energetic cost, making them noncompetitive isomers. Finally, the global minimum of the dimer [(Sn6Ge2Bi)2]4– presents the most stable monomers as assembly units. These results show the importance of considering the simultaneity of all of these conditions for the viability of these types of compounds.