Examinando por Autor "Fuentealba, P."

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    Hardness and softness kernels, and related indices in the spin polarized version of density functional theory
    (Elsevier, 2006-02) Guerra, D.; Contreras, R.; Perez, P.; Fuentealba, P.
    In this Letter, the mathematical expressions corresponding to the kernel, local and global spin softness have been derived, and their relationship with other indices have been explored. Introducing various spin kernels, the mathematical framework of the spin polarized version of the chemical reactivity indices have been completed. Furthermore, new linear response functions have been defined and their relationship with the softness hierarchy are exposed. Finally, the importance of some of these indices has been illustrated for the reactivity pattern of open shell molecules.
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    Ítem
    Local reactivity index as descriptor of benzene adsorption in cluster models of exchanged zeolite-Y
    (Elsevier, 2004-01) Santos, J.; Chamorro, E.; Contreras, R.; Fuentealba, P.
    The adsorption of benzene over sites I, II and III of Cu- and Na-exchanged zeolite-Y, has been studied using the energy profiles for the host-guess interaction, and electronic descriptors of reactivity such as the electronic chemical potential and a local σk index recently defined. Both, the energy and the reactivity index based models consistently complement each other to give a correct interpretation of the reactivity and selectivity patterns experimentally established for these systems.
  • Miniatura
    Ítem
    Magnetic properties of composites based on the intercalation of ZnII and CuII bimetallic macrocyclic complexes in the MnPS3 phase
    (RSC Advances, 2017) Fuentealba, P.; Paredes-Garcia, V.; Venegas-Yazigi, D.; Silva, I.D.A.; Magon, C.J.; Costa De Santana, R.; Audebrand, N.; Manzur, J.; Spodine, E.
    Asymmetric macrocyclic complexes of the type [M2LCl2]·xH2O have been obtained and intercalated using the potassium precursor phase K0.4Mn0.8PS3·H2O (M: ZnII or CuII; LH2: macrocyclic ligand derived from 2-hydroxy-5-methyl-1,3-benzenedicarbaldehyde and two different amines, namely, ethylenediamine and o-phenylenediamine). The intercalation of the layered phase K0.4Mn0.8PS3·H2O by the macrocyclic species was carried out by a microwave-assisted reaction and enabled the partial exchange of the hydrated potassium ions located in the interlayer space to obtain the composites K0.32[Zn2L]0.04Mn0.8PS3 (1) and K0.24[Cu2L]0.08Mn0.8PS3 (2). These magnetic materials were studied by DC and AC magnetization measurements and electron paramagnetic resonance (EPR) spectroscopy. In comparison with the potassium precursor, both composites gave rise to broader and less intense spontaneous magnetization curves at low temperatures. The composite K0.32[Zn2L]0.04Mn0.8PS3 (1) exhibited spontaneous magnetization in the form of one broad asymmetric maximum at 27 K. However, K0.24[Cu2L]0.08Mn0.8PS3 (2) had two defined maxima at 24 and 12 K. The observation of a maximum in the imaginary part of the AC susceptibility data implies the existence of a spin canting phenomenon that would be responsible for the spontaneous magnetization. The EPR results are qualitatively consistent with the magnetization data and reveal that exchange narrowing effects were responsible for the narrowing and broadening of the line shapes. © 2017 The Royal Society of Chemistry.