Benzidine Derivatives as Electroactive Materials for Aqueous Organic Redox Flow Batteries.

This paper presents a theoretical and experimental evaluation of benzidine derivatives as electroactive molecules for organic redox flow batteries. These redox indicators are novel electroactive materials that can perform multielectron transfers in aqueous media. We performed the synthesis, electrochemical characterization, and theoretical study of the dimer of sodium 4-diphenylamine sulfonate, a benzidine derivative with high water solubility properties.

Charge-transfer electronic states in organic solar cells: a TDDFT study.

The prediction of new organic photovoltaic materials in organic solar cells (OSCs) must include a precise description of charge-transfer states because they are involved in electron-transfer processes such as charge separation and charge recombination which govern the device efficiency. Also, as the experimental performance of an optoelectronic device is measured for nonequilibrium nanostructures, computational approaches need models that can incorporate morphology effects. Usually, this aspect is treated by molecular dynamics simulation (MDS) methodologies; however, methodologies and formalisms to calculate the electron-transfer processes are still controversial and sometimes do not connect their information with the phase morphologies.

Electronic structure data at ground and excited state of the structural and opto-electronic properties of organic photovoltaic materials.

This work presents data coming from electronic structure calculations at the Density Functional Theory level, performed in a series of organic photovoltaic materials. The data represents the Cartesian coordinates of such molecular systems at the lowest energy geometry and at the first excited state. Data evidencing the nature of the photo-isomerization in the OPV systems was also obtained.

Saliva is a reliable and accessible source for the detection of SARS-CoV-2.

Objectives: The aim of this study was to investigate the feasibility of saliva sampling as a non-invasive and safer tool to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to compare its reproducibility and sensitivity with nasopharyngeal swab samples (NPS). The use of sample pools was also investigated.

Methods: A total of 2107 paired samples were collected from asymptomatic healthcare and office workers in Mexico City.

Atomistic simulations of bulk heterojunctions to evaluate the structural and packing properties of new predicted donors in OPVs.

Organic photovoltaic materials (OPVs), with low cost and structure flexibility, are of great interest and importance for their application in solar cell device development. However, the optimization of new OPV structures and the study of the structure arrangements and packing morphologies when materials are blended takes time and consumes raw materials, thus theoretical models could be of considerable value. In this work, we performed molecular dynamics simulations of present OPVs to understand the morphological packing of the donor-acceptor (DA) phases and DA heterojunction during evaporation and annealing processes, following inter and intramolecular properties like frontier orbitals, π-π stacking, coordination, distances, angles, and aggregation.

Theoretical exploration of 2,2'-bipyridines as electro-active compounds in flow batteries.

Compounds from the 2,2'-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2'-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pKa for the second deprotonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations.

Parameterization of prototype organic small molecules suitable for OPVs and molecular dynamics simulations: the BTT and BPT cases.

Organic photovoltaics (OPV) have been theoretically studied within the usual parameters: open circuit voltage (V), short circuit current (J), and fill factor (FF). The first two refer mostly to electronic properties, whereas the last contains all other possible contributions to cell efficiency, importantly including molecular geometrical and topological structures, both within a single molecule as amongst a system of molecules. In order to study the effects of molecular morphology of the heterostructures used in OPVs, molecular dynamic simulations (MDS) are imperative, and therefore parameterization of force fields to account for the description of planarity between aromatic rings, both intra- and inter-molecules, is of key importance.

Reassessment of the Four-Point Approach to the Electron-Transfer Marcus-Hush Theory.

The Marcus-Hush theory has been successfully applied to describe and predict the activation barriers and hence the electron-transfer (ET) rates in several physicochemical and biological systems. This theory assumes that in the ET reaction, the geometry of the free Gibbs energy landscape is parabolic, with equal curvature near the local minimum for both reactants and products. In spite of its achievements, more realistic models have included the assumption of the two parabolas having not the same curvature.

Accelerating resolution-of-the-identity second-order Møller-Plesset quantum chemistry calculations with graphical processing units.

The modification of a general purpose code for quantum mechanical calculations of molecular properties (Q-Chem) to use a graphical processing unit (GPU) is reported. A 4.3x speedup of the resolution-of-the-identity second-order Møller-Plesset perturbation theory (RI-MP2) execution time is observed in single point energy calculations of linear alkanes.

Reagents for electrophilic amination: a quantum Monte Carlo study.

Electrophilic amination is an appealing synthetic strategy to construct carbon-nitrogen bonds. The authors explore the use of the quantum Monte Carlo method and a proposed variant of the electron pair localization function--the electron pair localization function density--as a measure of the nucleophilicity of nitrogen lone pairs as a possible screening procedure for electrophilic reagents.