bluuebunny/crossref_metadata_2025_split huggingface dataset:
Positively and Negatively Charged Porphyrin Metal Complexes That Form Ion-Pairing Assemblies
Authors: Maeda Hiromitsu 
Published: May 2020

An ordered arrangement of π-electronic species is crucial for the fabrication of functional organic materials such as organic electronic devices including field-effect transistors, light-emitting diodes, and photovoltaic cells. Synergetic uses of electrostatic interactions and other noncovalent interactions, including π–π stacking, is very important for the alignment of π-electronic charged species (cations and anions) and the formation of dimension-controlled assemblies including fiber and sheet solid materials, supramolecular gels, and liquid crystals.[1,2] An advantage of using electrostatic interactions is the formation of various ion-pairing materials by combining constituent π-electronic ions: for example, ten kinds of cations and ten kinds of anions are mixed to ideally provide one hundred kinds of ion pairs. Furthermore, assembling modes can be modulated by constituent ions as well as by the environment, thus exhibiting particular properties according to the arrangement of charged building units even in an ion pair. In this study, porphyrin–AuIII complexes were found to act as π-electronic cations which can combine with various counteranions, including π-electronic anions such as negatively charged porphyrin metal complexes. In the solid-state and soft materials, the formation of assemblies with contributions of charge-by-charge and charge-segregated assemblies, whose ionic components were highly organized by π–π stacking and electrostatic interactions, depended on the geometries and electronic states of constituent ionic species.[3,4]
References
1. Reviews: a) Haketa, Y.; Maeda, H. Bull. Chem. Soc. Jpn.
2018, 91, 420; b) Haketa, Y.; Urakawa, K.; Maeda, H. to be submitted.
2. Recent examples: a) Maeda, H.; Takeda, Y.; Haketa, Y.; Morimoto, Y.; Yasuda, N. Chem. Eur. J.
2018, 24, 8910; b) Maeda, H.; Okubo, T.; Haketa, Y.; Yasuda, N. Chem. Eur. J.
2018, 24, 16176; c) Yamakado, R.; Ishibashi, H.; Motoyoshi, Y.; Yasuda, N.; Maeda, H. Chem. Commun.
2019, 55, 326; d) Yamakado, R.; Haketa, Y.; Hara, M.; Nagano, S.; Seki, T.; Maeda, H. Chem. Commun. Chem. Commun.
2019, 55, 10269.
3. a) Haketa, H.; Bando, Y.; Sasano, Y.; Tanaka, H.; Yasuda, N.; Hisaki,I.; Maeda, H. iScience
2019, 14, 241; b) Tanaka, H.; Haketa, Y.; Yasuda, N.; Maeda, H. Chem. Asian J.
2019, 14, 2129; c) Tanaka, H.; Haketa, Y.; Bando, Y.; Yamakado, R.; Yasuda, N.; Maeda, H. to be submitted.
4. Assemblies of anionic porphyrins: Sasano, Y.; Haketa, Y.; Tanaka, H.; Yasuda, N.; Maeda, H. Chem. Eur. J.
2019, 25, 6712.
Pyrolysis of Self-Assembled Metalloporphyrins Toward ORR and/or CO2RR
Authors: Song Yujiang 
Published: May 2020

Oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO2RR) are of particular interest for energy conversion and storage and have drawn a lot of recent attentions. It is obvious that efficient electrocatalysts are highly needed to selectively accelerate the ORR and CO2RR at a low overpotential. Metalloporphyrins and the derivatives represent an important type of non-precious metal electrocatalysts (NPMEs). Herein, we introduce the synthesis of several types of metalloporphyrin-based NPMEs by pyrolysis of self-assembled porphyrins in the presence or absence of carbon supports. As-prepared NPMEs with core-shell structure or flower-like structure exhibit excellent performance toward ORR and CO2RR. This study shows that porphyrin-based materials may play an import role in the field of clean and renewable energy.

Keywords: oxygen reduction reaction, CO2 reduction reaction, metalloporphyrins, self-assembly, pyrolysis
References:
[1] Li, J.; Song, Y. J.; et al.
Adv.Funct. Mater. 2017, 27: 1604356.
[2] Cong, Y. Y.; Song, Y. J.; et al.
Nano Energy 2018, 44: 288.
[3] Zhang, X.; Song, Y. J.; et al. Chem. Commun. 2019, 55:5659.
[4] Xie, Y.; Song, Y. J.; et al. ACS Appl. Mater. Interfaces 2019, 11: 34203.
[5] Li, J.; Song, Y. J.; et al. J. Catal. 2019, 378: 113.
Application of Saddle-Distorted Porphyrins to Dioxygen Reduction
Authors: Kojima Takahiko 
Published: May 2020

Efficient and selective dioxygen (O2) reduction is an important process in biological dioxygen activation and also in fuel cells to gain a chemical potential. So far, O2 activation has been achieved using transition-metal complexes as observed in that by metalloenzymes such as cytochrome P-450. However, organic molecules have scarcely used for O2 reduction probably due to instability during redox reactions under oxic conditions. We report herein the utilization of diprotonated and saddle-distorted porphyrins for photocatalytic O2 reduction and unprecedented interconversion between O2 and H2O2.
The photocatalytic O2 reduction was performed using diprotonated dodecaphenylporphyrin (H4DPP2+) as a photocatalyst, 10-methyl-9,10-dihydroacridine (AcrH2) as a two-electron donor in CH3CN in the presence of CH2ClCOOH as a proton source.1 Under photoirradiation at 480 nm, H2O2 was produced in turnover number of > 3000 and turnover frequency of 500 h–1 in the yield of 99% and the quantum yield of 12%. The efficiency is the highest among porphyrin photocatalysts reported so far. This is due to a low energy level of the triplet excited state of H4DPP2+ to avoid energy transfer to 3O2 for the formation of 1O2.
On the other hand, an N22, N23-dimethylated H2DPP derivative (Me2Por) reacted with excess H2O2 to afford the corresponding isophlorin derivative (Me2IPh) and O2.2 The isophlorin derivative conversely reacted with O2 to form the dimethylated porphyrin and H2O2. This reversibility has been gained due to a small Gibbs free energy difference between the two states, Me2Por + H2O2 and Me2IPh + O2, and minimizing activation energy of the reaction. The hydrogen-bond formation, which is facilitated by the saddle distortion of the porphyrin to fix the direction of protons or lone pairs of the pyrroles, between Me2Por and H2O2 and between Me2IPh and O2 plays indispensable roles in each process to promote proton-coupled electron transfer. The interconversion can be repeated by converting the atmosphere between O2 and Ar at least 11 times without losing activity due to the robustness of the dimethylated porphyrin.

References

1. Aoki, W. Suzuki, H. Kotani, T. Ishizuka, H. Sakai, T. Hasobe, T. Kojima, Chem. Commun.
2019, 55, 4925.
2. W. Suzuki, H. Kotani, T. Ishizuka, T. Kojima, J. Am. Chem. Soc.
2019, 141, 5987.
Investigation By NMR Spectroscopy of the Structural Characteristics of Modified Oligo-Nucleotides with Pendant Porphyrins
Authors: Solladie Nathalie 
Published: May 2020

Exerting control over the position and distance of the porphyrins along a specifically designed oligonucleotidic scaffold was our main goal over the past years. Indeed, in naturally occurring light-harvesting complexes, biopolymer scaffolds hold pigments at intermolecular distances that optimize photon capture, electronic coupling, and energy transfer. We thus focused on the synthesis of four uridine-porphyrin conjugates (a monomer, dimer, tetramer and octamer) dedicated to adopt a pre-organized conformation with face-to-face porphyrins, and capable to self-organize in a stable sandwich type complexe with bidentate base such as DABCO. Using a similar strategy as the one used in antisense research, an artificial nucleotidic backbone was built from modified deoxy-uridine units linked with a more rigid linker than the phosphodiester moieties found in natural oligonucleotides. Antisense research uses modified oligonucleotides, less flexible than natural strands, to pre-organize the system toward the obtaining of stable double helices between synthesized and natural oligonucleotides. A modified oligonucleotidic backbone was here used to target a parallel conformation of the porphyrins appended to each deoxy-uridine moiety. To provide a rigid environment for the porphyrins, the uridine units were coupled in 3’-5’ stepwise fashion using ether-ester type of spacer of suitable length, and porphyrins were anchored to the uridine by means of robust carbon-carbon bonds.
To investigate the conformation of our four uridine-porphyrin conjugates, they were subjected to a comprehensive conformational analysis by using NMR spectroscopy. The collected NOE NMR data highlighted characteristic and strong interactions indicating that the glycosidic angle between the ribose and uracil base is anti. In order to further invastigate the conformation of this family of molecules, NMR experiments were carried out at variable temperature. At low temperature, the signals of the porphyrinic protons decoalesce showing two sets of b-pyrrolic protons. Similar observations are made for the signals corresponding to the sugar moieties and especially the H1’ protons, indicating molecular motions within our porphyrin-uridin arrays. These results testify in favor of the existence of a dynamic process between C3’-endo and C2’-endo conformations.
We thus document the fact that the choice of rigid spacers is not the only way to pre-organize bis-porphyrins, and that some well-chosen nucleosidic linkers offer an interesting option for the synthesis of such devices. Furthermore, the chirality and enantio-purity of the nucleosidic linkers paves the way toward the selective complexation of enantio-pure bidentate guests and the resolution of racemates.

Acknowledgements

This work was supported by the CNRS and the French Ministry of Research.

References

1. Merkas, M. Zinic, R. Rein, N. Solladié, J. Porphyrins Phthalocyanines
2019, 23, 797-812.

Figure 1
Embedded Ocv Based Model for State of Health Monitoring in a BMS
Authors: Radhakrishnan Karthik Narayanan , Prosser Ryan , Patel Yatish , Offer Gregory James 
Published: May 2020

Lithium ion batteries degrades with time. Battery diagnostics links observable changes in cell parameters to changes that have occurred inside the cell. More accurate diagnosis means a better insight into these internal changes which can aid in predicting failure modes, remaining life, aide in optimising future use.
In the case of electric vehicles, an on-board battery management system (BMS) could implement these diagnostic techniques to give real time information on the internal state of the pack. It can then dynamically adjust parameters such as state of charge (SOC) window, maximum power and maximum allowable temperature to optimise performance and pack longevity.
Models capable of predicting Li-ion battery health with higher accuracy are highly advanced, and computationally exhaustive requiring complex physics-based models or equivalent circuit models (ECM) that require exhaustive parameter fitting. Other techniques require measurements or hardware which are not available in typical applications and so are only suited to lab-based diagnostics.
Current diagnostic techniques are not suitable for in-situ applications; either the BMS does not have the computational capacity to run the models, or the measurements required are not available outside a laboratory environment. In this work, we propose an Open Circuit Voltage (OCV) based model that predicts the degradation of a cell accurately without needing extensive computational capacity.
This model has been embedded in a microcontroller with limited computing power which could form part of the BMS system that better predicts the state of health of the cell. The model uses the open circuit potentials of each electrode and fits them to the full cell voltage in order to identify the degradation modes. Typical modes include Loss of Lithium (LLI) and Loss of Active Material from either electrode (LAM).
The model does not require the solving of concurrent complex equations or the fitting of extensive parameters to an equivalent circuit whilst still being able to provide accurate insight into the cell’s internal changes.
Results from this work demonstrate the usefulness of such a system in electric vehicle and paves the way for implementation of smarter BMS in electric vehicles by manufacturers. This unlocks the potential to predict and increase the longevity of a battery pack whilst still providing optimal performance to the vehicle.
Novel in-Situ Methods for Real-Time Monitoring of Corrosion
Authors: Virtanen Sannakaisa 
Published: May 2020

The presentation will introduce recently developed new techniques that allow real-time monitoring of corrosion processes. The approach is based on simultaneous measurement of the cathodic kinetics of the H2 evolution reaction (HER) and the O2 reduction reaction (ORR) in real-time. The universal and non-destructive, in-situ methods based on monitoring the rates of the cathodic reactions enable the determination of sensitive, real-time corrosion rates for both atmospheric corrosion and immersion.
In the case of immersion, HER monitoring e.g. with gravimetric buoyancy H2 measurements is well established. Recently it was shown that gravimetric H2 measurements are also suitable to monitor atmospheric H2-type corrosion (for Mg alloys) [1]. A novel approach to measure HER rates during atmospheric exposure is introduced in this work. This is based on determining the pressure increase in a hermetically closed chamber with a pressure sensor. Regarding ORR, both volumetric measurements and pressure sensor based techniques are applicable to monitor the rate of consumption of O2 gas. In addition, a fibre optic O2 sensor can be employed to monitor ORR rates both under immersion and atmospheric corrosion conditions. A combination of these methods enables to monitor ORR and HER simultaneously. Therefore, also corrosion systems where both HER and ORR contribute to the cathodic reaction can be monitored (e.g., Fe and Zn corrosion). Examples for the different scenarios and approaches will be demonstrated. Comparing the total cathodic charge recorded by the new monitoring techniques with mass loss measurements shows an excellent correlation. Moreover, combining the above described approaches with a flow cell setup expands the possible corrosion scenarios to be investigated. The flow cell enables switching between exposure conditions (e.g., electrolyte composition, temperature, flow rate,...) with a real-time response of the corrosion rate.
The techniques presented on one hand are of interest for corrosion monitoring, but on the other side also reveal mechanistic information on corrosion reactions.
[1] M. Strebl, S. Virtanen, J. Electrochem. Soc., 166 (11), C3001-C3009 (2019).
Discussion on Inductive Loop Observed in Complex Plane Plot of Electrochemical Impedance of Mg
Authors: Itagaki Masayuki 
Published: May 2020

Electrochemical impedance spectroscopy (EIS) is able to discriminate several time constants involved in electrode reactions. The time constant regarding adsorption-desorption relaxation may be detected in the plot of impedance spectrum when the adsorption at liquid/solid interface contributes to the kinetics of electrode reaction. For example, the complex plane plots of the electrochemical impedance of Pt electrode, where oxygen reduction occurs, show an apparent inductive loop, indicating the presence of the reaction intermediate adsorbed on the electrode1). The inductive loop is often observed in the cases of metal dissolutions in aqueous solutions2-4), and the origin has been explained by the adsorption of adsorbed intermediate in dissolution reaction. In this presentation, the author derives the theoretical equations of the Faraday impedance involving the contribution of adsorption process during metal dissolution. A current i, which flows across liquid/solid interface, is a function of electrode potential E and surficial coverage θ of adsorbed species as follows.

i = f(E, θ) (1)
The Faradaic impedance Z
F can be represented from the differential calculus of the equation (1), where, a
1 and a
1 are partial differential coefficients.
1/Z
F = di/dE = a
1 + a
2(dθ/dE) (2)
The equation (2) indicates that the Faradaic impedance is a function of (dθ/dE) and describes a semicircle due to an adsorption relaxation on the complex plane. In these cases, the semicircle in the low frequency range is related to the time constant of adsorption and desorption of the reaction intermediate. The conditions that the electrochemical impedance shows the inductive loop in the low frequency range are discussed on the basis of the numerical simulations.
References
1) M. Itagaki, H. Hasegawa, K. Watanabe, T. Hachiya, J. Electroanal Chem 557 (2003) 59.
2 M. Keddam, O. R. Mattos, H. Takenouti, J. Electrochem. Soc, 128 (1981) 257.
3) M. Itagaki, M. Tagaki, K. Watanabe, Electrochim.Acta, 41 (1996) 1201.
4) G. Baril, G. Galicia, C. Deslouis, N. Pebere, B. Tribollet, V. Vivier, J. Electrochem. Soc, 154 (2007) C108.
Investigation of AISI 316 Stainless Steel Corrosion in Perchloric Acid
Authors: Ostapenko Gennady I. 
Published: May 2020

The synthesis of 4,4-dimethyl-1,3-dioxane for the production of isoprene in perchloric acid is carried out. The synthesis apparatus is made of AISI 316 stainless steel. Here, AISI 316 steel corrosion in pure perchloric acid and in the presence of benzotriazole as a corrosion inhibitor is investigated by the potentiodynamic method.

Figure 1 shows the polarization curves in 1 M perchloric acid at various concentrations of benzotriazole. It is seen that with an increase in the inhibitor concentration, the curves shift to the cathode side and the cathode currents decrease more strongly than the anode currents. Therefore, benzotriazole in perchloric acid is an cathodic action inhibitor.
The Tafel relation for the polarization curve can be represented as the equation (1) of a straight line, which is convenient for determining the corrosion currents icorr
. Polarization curves at various inhibitor concentrations are shown in Figure 2 in the coordinates of this equation. Here icorr
was defined as currents at (Е – Еcorr
) = 0.
Corrosion currents, corrosion rates and inhibition efficiencies for various concentrations of benzotriazole are given in the Table.

Figure 1
Wafer-Scale Fabrication of Solid-State on-Chip Microsupercapacitors Based on Silicon-Processing Techniques
Authors: Choi Christopher S , Taberna Pierre-Louis , Lethien Christophe , Simon Patrice , Dunn Bruce S. 
Published: May 2020

Conventional silicon-based fabrication techniques, ranging from photolithography to various etching processes, are well-established approaches for achieving high-resolution patterns for microelectronics in the semiconductor industry. Although the use of microfabrication methods in the production of electrochemical energy storage (EES) devices has not really been considered, the adaption of these silicon processing techniques can open up new fabrication routes especially for integrated on-chip energy storage devices. One important consideration for the development of on-chip EES devices is to fabricate a mechanically rigid solid electrolyte with spatial and thickness control, which can be achieved using photopatterning functionality.1

This presentation will review our results on the synthesis and characterization of a photopatternable, ionically conducting solid electrolyte for on-chip micro-supercapacitors (MSC). Our approach was to create ‘quasi-solid’ electrolytes in which the photopatternable epoxy-based polymer matrix (SU-8) confines charge-carrying ions to provide measurable ionic conductivity. The resulting ion modified electrolyte is a promising gel polymer electrolyte with excellent thermal and physical properties and a room temperature ionic conductivity of 10-4 S cm-1. In addition, we demonstrate wafer-scale fabrication of all-photopatterned solid-state MSC devices. Electrochemical testing of tandem MSC devices validated that the potential range and total current output of MSC devices can easily be tailored through modifying the device arrangements in series or parallel configurations. The proposed fabrication strategy, based on magnetron sputtering of electrode materials in conjunction with a photopatternable solid electrolyte, provides a unique opportunity for the development of robust solid-state MSC that can be integrated with microelectronics in a single chip.
Reference
1. Choi, J. Lau, J. Hur, L. Smith, C. Wang, B. Dunn, Advanced Materials. 30 (2017) 1703772.
Measurement of Oxygen Transport through Separators in Flooded Batteries
Authors: Hostetler Eric , Duchateau Kaylee , Waterhouse Robert 
Published: May 2020

An in-depth understanding of oxygen transport in flooded lead acid batteries is necessary to better understand and mitigate water loss in the next generation of batteries for start-stop vehicle applications. The presence of the oxygen cycle leads to a lower rate of water loss observed during intermittent drive cycle testing compared to the gassing that would be calculated from the integrated overcharge current into the battery [1]. A model of the oxygen cycle in flooded lead acid batteries has been proposed [2] but until recently the oxygen transport through the separator-electrolyte system hasn’t been measured.
A method for measuring oxygen transport through the separator-electrolyte system has been developed which uses electrodes harvested from commercial batteries. In this method, the separator is sealed between two chambers of a test cell, one containing the positive electrode and the other containing the negative electrode plus a reference. A constant stream of oxygen is delivered to the positive side of the cell using an air pump and diffuser. The negative side is purged, sealed and constantly stirred. The cell is charged and allowed to rest at OCV. Oxygen diffuses from the constant source on the positive side to the negative side where it oxidizes some of the negative active mass. This creates a measurable capacity change at the negative electrode which can be measured during a potentiostatically-controlled recharge cycle.
We will report on measurements of oxygen transport through the separator-electrolyte system for different separator materials in a flooded cell using commercial lead acid electrodes. Results are compared with modeling of the oxygen cycle and related to factors in the separator which influence the oxygen transport rate, such as porosity, pore size distribution and tortuosity,.
[1] Wirth, 16ELBC, 07 September 2018, Vienna Austria
[2] Meissner, Scientific Workshop: High-Temperature Durability Tests for Advanced Lead 12-V Batteries, 30 January 2017, Kloster Eberbach, Germany