Publicaciones 2011-2020

@article{RN308,
title = {Catalytic Aspects of Metallophthalocyanines Adsorbed on Gold-Electrode. Theoretical Exploration of the Binding Nature Role},
author = { S. Miranda-Rojas and P. Sierra-Rosales and A. Munoz-Castro and R. Arratia-Perez and J.H. Zagal and F. Mendizabal},
url = {/brokenurl#<Go to ISI>://WOS:000387024300053},
doi = {10.1039/c6cp06156g},
issn = {1463-9076},
year = {2016},
date = {2016-01-01},
journal = {Physical Chemistry Chemical Physics},
volume = {18},
number = {42},
pages = {29516-29525},
abstract = {The need of deeper insights regarding the inner working of catalysts represents a current challenge in the search of new ways to tune their activities towards new chemical transformations. Within this field, metallophthalocyanines-based (MPc) electrocatalysis has gained tremendous attention due to their versatility, low cost, great stability and excellent turn-over properties. In this concern, here we present a quantum chemical study of the formation of supramolecular complexes based on the adsorption of MPcs on gold substrates, and the effect of the substrate on their electrocatalytic properties. For this purpose, we used iron-(FePc), cobalt( CoPc) and copper-phthalocyanines (CuPc). To model the gold surface we used two gold clusters of different sizes, given by Au-26 and Au-58 accounting for gold electrode Au(111) surface. Thus, both electronic and binding strength features of the adsorption process between the complexes were analyzed in detail in order to gain a deeper description of the nature of the MPc-Au(111) formation, by using Density Functional Theory (DFT) calculations, at the PBE and TPSS levels including the dispersive contribution according to the Grimme approach (D3). Our results show that dispersion forces rule the MPc-gold interaction, with binding strengths ranging between 61 and 153 kcal mol(-1), in agreement to the reported experimental data. To provide a detailed picture of our findings we used the non-covalent interactions index (NCIs) analysis, which offers additional chemical insights regarding the forces that control their interaction strength. Finally, our calculations revealed that among the three MPcs, CuPc required less energy for its oxidation. However, the removal of the electron involves a tremendous decrease of the MPc-gold surface interaction strength thus suggesting its desorption, which would prevent the required reversibility of the redox reaction, explaining its low performance observed experimentally.},
keywords = {complexes, fe iron-phthalocyanine, metal monolayers, oxidation phthalocyanines, pseudopotentials, scanning-tunneling-microscopy, self-assembled supramolecular surfaces},
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}
}