Publicaciones 2011-2020

@article{RN359,
title = {Electronic Structure and Optical Properties Calculation of Zn-Porphyrin with N-Annulated Perylene Adsorbed on Tio2 Model for Dye-Sensitized Solar Cell Applications: A Dft/Td-Dft Study},
author = { K. Paredes-Gil and F. Mendizabal and D. Paez-Hernandez and R. Arratia-Perez},
url = {/brokenurl#<Go to ISI>://WOS:000389089900058},
doi = {10.1016/j.commatsci.2016.09.042},
issn = {0927-0256},
year = {2017},
date = {2017-01-01},
journal = {Computational Materials Science},
volume = {126},
pages = {514-527},
publisher = {2016 Elsevier B.V.},
abstract = {The current work scrutinizes the chemical behavior of a set of promissory dyes, the Zn-porphyrins with N-annulated Perylene, WW3m-WW8m, within the most important steps in the solar cell: photoexcitation, electron injection and dye regeneration. The photoexcitation step was studied through TD-DFT frame-work, finding that the most intense band in WW4m, WW6m-WW8m corresponds to the electronic transition of the frontier orbitals HOMO-LUMO. Among these, WW6m is highlighted, because the electronic density of the LUMO is localized over the anchoring group. Therefore, the presence of two ethynylene spacers in the WW6m porphyrin originate an enhancement in the light absorption. On the other hand, we analyze the electron injection modelling two (mono and bidentate) adsorbing modes in WW3m
@Ti0(2)-WW8m
@TiO2 using DFT (B3LYP+D3) calculations. Adsorption energies. show that WW3m
@Ti0(2)-WW8m
@TiO2 are coordinated in bidentate mode. In this sense, to analyze the density of states (DOS) we found that WW6m
@TiO2 present the narrowest band gap (1.53 eV), promoting an easy electron injection, which could explain the origin of the highest overall efficiency of the solar cell for this porphyrin. Finally, dye regeneration, was studied through the free energy associated, Delta G(regen,) the values are between -6.61 and -6.93 eV for WW3m
@Ti02-WW8m
@TiO2 showing that this step is spontaneous and similar in all porphyrins.},
keywords = {computational density-functional dye, efficiency, electrochemistry, energy-levels, excited-states, families, light-harvesting model, n-annulated n719 perylene properties, related solar spectroscopic studies, theory, tio2 zn-porphyrin},
pubstate = {published},
tppubtype = {article}
}

@article{RN343,
title = {Theoretical Insights into the Regioselectivity of a Pictet-Spengler Reaction: Transition State Structures Leading to Salsolinol and Isosalsolinol},
author = { I. Almodovar and M.C. Rezende and B.K. Cassels and M. Garcia-Arriagada},
url = {/brokenurl#<Go to ISI>://WOS:000406979900005},
doi = {10.1002/poc.3666},
issn = {0894-3230},
year = {2017},
date = {2017-01-01},
journal = {Journal of Physical Organic Chemistry},
volume = {30},
number = {8},
abstract = {The mechanism of the cyclization step of the Pictet-Spengler reaction between acetaldehyde and dopamine to give salsolinol and isosalsolinol was studied computationally, using density functional theory. The preferential formation in acidic media of salsolinol, the product of para-cyclization, and the requirement of a neutral pH for the formation of the ortho-cyclized isosalsolinol are explained in terms of 2 different mechanistic routes with an iminium ion or a phenolate-iminium zwitterion as starting reactants.},
keywords = {borylation, calculations, catalyzed condensation, density-functional-approach, derivatives dft dopamine, frontier-electron isosalsolinol, mechanism, norcoclaurine of pictet-spengler regioselectivity, salsolinol, synthase, tautomerism, theory},
pubstate = {published},
tppubtype = {article}
}

@article{RN208,
title = {Surface Enhanced Raman Scattering Study of the Antioxidant Alkaloid Boldine Using Prismatic Silver Nanoparticles},
author = { M.A. Herrera and G.P. Jara and R. Villarroel and A.E. Aliaga and J.S. Gomez-Jeria and E. Clavijo and C. Garrido and T. Aguayo and M. Campos-Vallette},
url = {/brokenurl#<Go to ISI>://WOS:000340330900076},
doi = {10.1016/j.saa.2014.05.070},
issn = {1386-1425},
year = {2014},
date = {2014-01-01},
journal = {Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy},
volume = {133},
pages = {591-596},
publisher = {2014 Elsevier B.V.},
abstract = {Prismatic silver nanoparticles (PNps) were used in the surface enhanced Raman scattering (SEAS) study of the antioxidant alkaloid boldine (5,6,6a,7-tetrahydro-1,10-dimethoxy-6-methyl-4H-dibenzo[de,g]quinoline-2,9-diol). Prismatic and quasi-spherical (QsNps) silver nanoparticles were synthesized and characterized by UV Vis spectra, topographic profile (AFM) and zeta potential measurements. Raman and infrared (IR) spectra of the boldine were registered. Theoretical model calculations of the boldine onto the Ag surface predict a nearly coplanar orientation of the benzo[de]quinoline moiety and non-bonded interactions (electrostatic).},
keywords = {approximations, aromatic-hydrocarbons, boldine, enhanced extended hartree-fock huckel molecular-orbital nanoparticles, polycyclic prismatic raman scattering, sers silver spectroscopy, surface theories, theory, type},
pubstate = {published},
tppubtype = {article}
}

@article{garrido2012interaction,
title = {Interaction of the C-Terminal Peptide from Pigeon Cytochrome C with Silver Nanoparticles. A Raman, Sers and Theoretical Study},
author = { C. Garrido and A.E. Aliaga and J.S. Gomez-Jeria and J.J. Carcamo and E. Clavijo and M. Campos-Vallette},
url = {/brokenurl#<Go to ISI>://WOS:000304686400014},
doi = {10.1016/j.vibspec.2012.01.011},
issn = {0924-2031},
year = {2012},
date = {2012-01-01},
journal = {Vibrational Spectroscopy},
volume = {61},
pages = {94-98},
publisher = {2012 Elsevier B.V.},
abstract = {The Raman and surface-enhanced Raman scattering (SERS) spectra of the C-terminal peptide of pigeon cytochrome C (PCC87-104). were recorded. This peptide is widely used to study the immune response in vivo. Hydrophobicity and net charge parameters of PCC87-104, allowed prediction of the nature of its interaction with colloidal nanostructured silver surfaces. The SERS spectrum provided information about the organization and orientation of PCC87-104 on the surface of silver nanoparticles (AgNPs). The batch to batch reproducible SERS spectra were obtained by adding the colloidal AgNPs solution onto the dried analyte sample. On the basis of the SERS information and the analysis of the net charge of each amino acid residue in the peptide sequence, it is concluded that the interaction of the peptide and the AgNPs is mainly induced and oriented by the lysine residues. The spectroscopic results are supported by quantum chemical calculations, performed by using Extended Huckel theory for a model of PCC87-104 interacting with a silver surface.},
keywords = {amino-acids, approximations aromatic-hydrocarbons, charge, enhanced extended hartree-fock huckel hydrophobicity, molecular-orbital net pcc87-104 peptide, polycyclic proteins, raman raman, scattering, spectroscopy, surface, surface-enhanced theories, theory, type},
pubstate = {published},
tppubtype = {article}
}

@article{RN425,
title = {Electrochemical, Esr and Theoretical Insights into the Free Radical Generation by 1,1 '-Hydrocarbylenebisindazoles and Its Evaluation as Potential Bio-Active Compounds},
author = { B. Aguilera-Venegas and C. Olea-Azar and V.J. Aran and J.D. Maya and U. Kemmerling and H. Speisky and F. Mendizabal},
url = {/brokenurl#<Go to ISI>://WOS:000306399700009},
issn = {1452-3981},
year = {2012},
date = {2012-01-01},
journal = {International Journal of Electrochemical Science},
volume = {7},
number = {7},
pages = {5837-5863},
abstract = {A comprehensive multidisciplinary study is conducted here in order to assess the electrochemical behavior of a series of 1,1'-hydrocarbylenebisindazoles derivatives and its potential use as anti-T.cruzi drugs. At first, we have determined the electrochemical reduction mechanisms of this family by cyclic voltammetry (CV) studies, from which three kind of reduction mechanisms -depending on the substituent at positions 3 and 3'-were established, but sharing a first common step corresponding to the generation of a nitro anion radical, which was corroborated by ESR spectroscopy, showing a comparable hyperfine splitting pattern and a strong influence on the ESR spectral linewidths due to the radical-solvent interactions. Furthermore, in order to give a rational description about the electrochemical and ESR results, open- and closed-shell structures of bisindasoles were subjected to theoretical estimations at different levels of theory. For open-shell structures, the hyperfine splitting patterns were confirmed while for the closed-shell systems case, clear evidence about the electrochemical reactivity -in terms of their frontiers orbitals-were obtained. To conclude, all these compounds were assayed as growth inhibitors against T. cruzi, from which some degree of activity was observed for this family, highlighting a compound almost as active as the reference drug. Finally, in order to get some information about the potential action mechanisms involved in the trypanocidal activity, molecular modeling and spin trapping studies were also done.},
keywords = {antiprotozoal biological bisnitroindazoles, carbonyl chagas-disease control, density-functional derivatives, electron-spin-resonance, evaluation, free metabolism microsomal oxidative production, radical, reductase, reduction, ros spin stress, theory, thiol trapping, trypanosoma-cruzi, trypanothione},
pubstate = {published},
tppubtype = {article}
}

@article{RN107,
title = {A Local Extension of the Electrophilicity Index Concept},
author = { A. Cedillo and R. Contreras},
url = {/brokenurl#<Go to ISI>://WOS:000311506100005},
issn = {1870-249x},
year = {2012},
date = {2012-01-01},
journal = {Journal of the Mexican Chemical Society},
volume = {56},
number = {3},
pages = {257-260},
abstract = {A local measure of the electrophilicity has been recently proposed to analyze the chemical reactivity of several kinds of molecules. In this work a theoretical rationalization of the local extension is proposed following the quantitative definition of the molecular electrophilic power and a variational method for the distribution of the transferred charge. A condensation scheme to atoms or fragments follows from its relation to the Fukui function and the local softness. Differences between these quantities are discussed and they are tested in a model system. The analysis shows that the local electrophilicity is more appropriate to describe differences among a set of substituted molecules.},
keywords = {chemical chemical-reactivity, concept, density density-functional descriptors, electrophilicity, fukui function, functional hardness, intermolecular local parameter philicity reactivity, selectivity, softness, theory},
pubstate = {published},
tppubtype = {article}
}

@article{RN83,
title = {Enhancement of the Catalytic Activity of Fe Phthalocyanine for the Reduction of O-2 Anchored to Au(111) Via Conjugated Self-Assembled Mono Layers of Aromatic Thiols as Compared to Cu Phthalocyanine},
author = { I. Ponce and J.F. Silva and R. Onate and M.C. Rezende and M. Paez and J.H. Zagal and J. Pavez and F. Mendizabal and S. Miranda-Rojas and A. Munoz-Castro and R. Arratia-Perez},
url = {/brokenurl#<Go to ISI>://WOS:000306725200017},
doi = {10.1021/jp301093q},
issn = {1932-7447},
year = {2012},
date = {2012-01-01},
journal = {Journal of Physical Chemistry C},
volume = {116},
number = {29},
pages = {15329-15341},
abstract = {We have prepared self-assembled monolayers (SAMs) of 4-aminothiophenol (4-ATP) and 1-(4-mercaptophenyl)-2,6-diphenyl-4-(4-pyridyl)pyridinium tetrafluoroborate (MDPP) functionalized with iron phthalocyanine (Fe Pc) and copper phthalocyanine (Cu Pc) adsorbed on gold (111) electrodes. The catalytic activity of these SAMs/MPc was examined for the reduction of O-2 in aqueous solutions and compared to that of bare gold and with gold coated directly with preadsorbed MPc molecules. Scanning tunneling microscopy (STM) studies confirm the functionalization of the 4-ATP by MPc. STM images reveal that iron phthalocyanine molecules are chemically anchored to 4-aminothiophenol organic monolayers, probably having an "umbrella" type orientation with regards to the surface. The electrocatalytic studies carried out with Au/4-ATP/FePc and Au/MDPP/FePc electrodes show that the O-2 reduction takes place by the transfer of 4-electron to give water in contrast to a 2-electron transfer process observed for the bare gold. The modified electrode obtained by simple adsorption of FePc directly to the Au(111) surface still promotes the 4-electron reduction process, but it shows a lower activity than the electrodes involving SAMs with FePc molecules positioned at the outmost portion of the self-assembled monolayers. The activity of the electrodes increases as follow: Au < Au/FePc < Au/4-ATP/FePc < Au/MDPP/FePc with the highest activity when FePc molecules are more separated from the Au surface. In contrast, the less active CuPc shows almost the same activity in all three configurations. Theoretical calculations suggest the importance of the back-bonding into the adduct formation, showing the relevance of the supporting gold surface on the electron-transfer process mediated by anchoring ligands.},
keywords = {activity, alkylation, density-functional electrocatalytic electronic-structure, electroreductive hydrogen-peroxide, iron materials, metal-complexes molecular oxygen phthalocyanine, reduction, scanning-tunneling-microscopy, theory},
pubstate = {published},
tppubtype = {article}
}

@article{RN13,
title = {A Computationally Efficient and Reliable Bond Order Measure},
author = { R. Mera-Adasme and F. Mendizabal and C. Olea-Azar and S. Miranda-Rojas and P. Fuentealba},
url = {/brokenurl#<Go to ISI>://WOS:000289824500031},
doi = {10.1021/jp107498h},
issn = {1089-5639},
year = {2011},
date = {2011-01-01},
journal = {Journal of Physical Chemistry A},
volume = {115},
number = {17},
pages = {4397-4405},
abstract = {Bond order indexes are useful measures that connect quantum mechanical results with chemical understanding. One of these measures, the natural bond order index, based on the natural resonance theory procedure and part of the natural bond orbital analysis tools, has been proved to yield reliable results for many systems. The procedure's computational requirements, nevertheless, scales so highly with the number of functions in the basis set and the delocalization of the system, that the calculation of this bond order is limited to small or medium size molecules. We present in this work a bond order index, the first order perturbation theory bond order (fopBO), which is based on and strongly connected to the natural bond orbital analysis tools. We present the methodology for the calculation of the fopBO index and a number of test calculations that shows that it is as reliable as the natural bond orbital index, with the same weak sensitivity to variations among commonly used basis sets and, as opposed to the natural bond order index, suitable for the study of large systems, such as most of those of biological interest.},
keywords = {auxiliary basis-sets, density, electron elements, exchange, localization, natural program resonance split-valence, superoxide-dismutase, theory, zinc},
pubstate = {published},
tppubtype = {article}
}