Raúl Mera‐Adasme

University of Tarapacá

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Moisés Domínguez

Universidad de Santiago de Chile

Dage Sundholm

University of Helsinki

Paulo C. T. Souza

Inserm

‪J

‪Siewert J. Marrink

University of Groningen

Rocío Araya‐Osorio

University of Tarapacá

Luís Borges-Araújo

École Normale Supérieure de Lyon

Sangwook Wu

Pukyong National University

Fernando Mendizábal

University of Chile

Riccardo Alessandri

University of Chicago

Christian Ochsenfeld

Ludwig-Maximilians-Universität München

Cooperative Institutions

Universidad de Santiago de Chile

University of Helsinki

University of Chile

Centre National de la Recherche Scientifique

Universidad Bernardo O'Higgins

Université Claude Bernard Lyon 1

University of Groningen

Universidad Andrés Bello

Ludwig-Maximilians-Universität München

Universidad de Oviedo

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Computational Studies of the Metal-Binding Site of the Wild-Type and the H46R Mutant of the Copper, Zinc Superoxide Dismutase

Inorganic Chemistry (2012)

Raúl Mera‐Adasme Fernando Mendizábal Maurício González Sebastián Miranda‐Rojas Claudio Olea‐Azar

Impairment of the Zn(II)-binding site of the copper, zinc superoxide dismutase (CuZnSOD) protein is involved in a number of hypotheses and explanations for the still unknown toxic gain of function mutant varieties of CuZnSOD that are associated with familial forms of amyotrophic lateral sclerosis (ALS). In this work, computational chemistry methods have been used for studying models of the metal-binding site of the ALS-linked H46R mutant of CuZnSOD and of the wild-type variety of the enzyme. By comparing the energy and electronic structure of these models, a plausible explanation for the effect of the H46R mutation on the zinc site is obtained. The computational study clarifies the role of the D124 and D125 residues for keeping the structural integrity of the Zn(II)-binding site, which was known to exist but its mechanism has not been explained. Earlier results suggest that the explanation for the impairment of the Zn(II)-site proposed in this work may be useful for understanding the mechanism of action of the ALS-linked mutations in CuZnSOD in general.

Wild type

10.1021/ic202416d

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Citations (12)

Insights on the Reactivity of Terminal Phosphanido Metal Complexes toward Activated Alkynes from Theoretical Computations

Inorganic Chemistry (2017)

Daniel Álvarez Raúl Mera‐Adasme L. Riera Gloria Cárdenas‐Jirón J. Pérez

Herein we present a theoretical study on the reaction of [Re(PPh2) (CO)3(phen)] (phen = 1,10-phenanthroline) and [Re(PPh2) (CO)3(bipy)] (bipy = 2,2'-bipyridine) toward methyl propiolate. In agreement with experimental results for the phen ligand, the coupling of the substituted acetylenic carbon with the nonsubstituted ortho carbon of the phen ligand is the preferred route from both kinetic and thermodynamic viewpoints with a Gibbs energy barrier of 18.8 kcal/mol and an exoergicity of 11.1 kcal/mol. There are other two routes, the insertion of the acetylenic fragment into the P-Re bond and the coupling between the substituted acetylenic carbon and a carbonyl ligand in cis disposition, which are kinetically less favorable than the preferred route (by 2.8 and 1.9 kcal/mol, respectively). Compared with phen, the bipy ligand shows less electrophilic character and also less π electron delocalization due to the absence of the fused ring between the two pyridine rings. As a consequence, the route involving the coupling with a carbonyl ligand starts to be kinetically competitive, whereas the product of the attack to bipy is still the most stable and would be the one mainly obtained after spending enough time to reach thermal equilibrium.

Reactivity

10.1021/acs.inorgchem.7b00767

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On the Mechanism of the Reactivity of 1,3‐Dialkylimidazolium Salts under Basic to Acidic Conditions: A Combined Kinetic and Computational Study

Angewandte Chemie International Edition (2018)

Daniel Rico del Cerro Raúl Mera‐Adasme Alistair W. T. King Jesús E. Perea‐Buceta Sami Heikkinen

Abstract Comprehensive spectroscopic kinetic studies illustrate an alternative mechanism for the traditional free‐carbene intermediated H/D exchange reaction of 1,3‐dialkylimidazolium salts under neutral (D 2 O) and acidic conditions (DCl/D 2 O 35 wt % solution). The deuteration of high purity [bmim]Cl in D 2 O is studied at different temperatures, in absence of catalyst or impurities, to yield an activation energy. DFT transition‐state modelling, of a small water cluster and [bmim] cation, also yields an activation energy which strongly supports the proposed mechanism. The presence of basic impurities are shown to significantly enhance the exchange reaction, which brings into question the need for further analysis of technical purities of ionic liquids and the implications for a wide range of chemical reactions in such media.

Reactivity

10.1002/anie.201805016

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A Computationally Efficient and Reliable Bond Order Measure

The Journal of Physical Chemistry A (2011)

Raúl Mera‐Adasme Fernando Mendizábal Claudio Olea‐Azar Sebastián Miranda‐Rojas Patricio Fuentealba

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.

Bond market index

Natural bond orbital

10.1021/jp107498h

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Aminocarbonyl Fluorophores with a Strong Emissive Inverted Solvatochromism

The Journal of Physical Chemistry Letters (2024)

Simone Morales Matías Vidal Fabián Martínez‐Gómez Raúl Mera‐Adasme Carolina Aliaga

Three aminocarbonyls were synthesized, and their emissive spectral behavior recorded at various solvent polarities showed marked inverted solvatofluorochromism. The emission energy inversion occurs at moderate solvent polarities and was found to be triggered by a change in the solute-solvent interaction responsible for the stabilization of the highly zwitterionic excited state of the dyes, from dipolarity to acidity.

Solvatochromism

10.1021/acs.jpclett.4c02457

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A comparison of computational methodologies for the structural modelling of biologically relevant zinc complexes

Journal of Molecular Modeling (2019)

Gökçen Savaşçı Merlys Borges‐Martínez Raphael J. F. Berger Christian Ochsenfeld Raúl Mera‐Adasme

10.1007/s00894-019-4139-8

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Citations (1)

On the physical-chemical nature of solvent polarizability and dipolarity

Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy (2019)

Raúl Mera‐Adasme Marcos Caroli Rezende Moisés Domínguez

Solvatochromism

10.1016/j.saa.2019.118008

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Citations (12)

Synthesis and study of the trypanocidal activity of catechol-containing 3-arylcoumarins, inclusion in β-cyclodextrin complexes and combination with benznidazole

Arabian Journal of Chemistry (2021)

Josué Pozo-Martínez Francisco Salgado Ana Liempi Ulrike Kemmerling Raúl Mera‐Adasme

American trypanosomiasis or Chagas disease is caused by the protozoan parasite Trypanosoma cruzi, and is considered a neglected disease, being an important problem for public health. Benznidazole (BZN) is the drug used to treat the disease. However, it has limited efficacy and adverse side effects. Therefore, the development of new therapeutic alternatives is necessary. In this work, the trypanocidal activity and cytotoxicity of a series of catechol-containing 3-arylcoumarins, their combination with BZN, and the inclusion in β-cyclodextrins (β-CDs), were evaluated. The results obtained showed that the entire series has moderate trypanocidal activity on the trypomastigote form of the parasite, being the 3-(4′-bromophenyl)-6,7-dihydroxycoumarin (8) the most active compound (IC50 = 34 μM) and the most cytotoxic in Vero cells (IC50 = 162 μM) as well. By forming the inclusion complex 8-β-CDs, the trypanocidal activity and cytotoxicity decreased. In addition, the formation of inclusion complexes increased the solubility. The possible mechanism of action of 8 was evaluated and proved to be through the generation of oxidative stress. The combination with BZN presented a synergistic effect on the trypanocidal activity, reducing the necessary dose of BZN. The presence of a catechol in the studied scaffold seems to modulate the trypanocidal activity, and the combination of drugs proved to be a promising alternative strategy for treating the disease.

Benznidazole

Trypanocidal agent

Chagas Disease

Catechol

10.1016/j.arabjc.2021.103641

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Citations (6)