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Auteur : Grafiati
Publié le 10 mars 2023

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1

Mohammadpourasl, Sanaz, Fabrizia Fabrizi de Biani, Carmen Coppola, Maria Laura Parisi, Lorenzo Zani, Alessio Dessì, Massimo Calamante, Gianna Reginato, Riccardo Basosi et Adalgisa Sinicropi. « Ground-State Redox Potentials Calculations of D-π-A and D-A-π-A Organic Dyes for DSSC and Visible-Light-Driven Hydrogen Production ». Energies 13, no 8 (19 avril 2020) : 2032. http://dx.doi.org/10.3390/en13082032.

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The prediction of ground-state redox potentials by quantum chemical methods has a prominent role in the rational design of novel organic photosensitizers both for dye-sensitized solar cells (DSSCs) and photocatalytic systems for the production of H2. Indeed, the ground-state redox potential of the photosensitizers is one of the key parameters to identify the most promising candidates for such applications. Here, the ground-state redox potentials of 16 organic donor-π-acceptor D-π-A and donor-acceptor-π-acceptor D-A-π-A dyes having a medium to large size of the conjugated scaffold are evaluated, using the methods of the Density Functional Theory (DFT), in terms of free energy differences between their neutral and oxidized ground-state forms. These results are compared to the available experimental data and to the computed highest occupied molecular orbital energy −ε(HOMO) values as an approximation of ground-state redox potentials according to Koopmans’ theorem. Using the MPW1K functional in combination with the 6-31+G* basis set, the strategy based on the free energy cycle, including solvent effects, reproduces with a good level of accuracy the observed values (mean absolute error (MAE) < 0.2 eV) and trend of redox potentials within related families of dyes. On the other hand, the −ε(HOMO) values are only able to capture the experimental trends in redox potential values.
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Kim, Dooyoung, et Thomas S. Teets. « Strategies for accessing photosensitizers with extreme redox potentials ». Chemical Physics Reviews 3, no 2 (juin 2022) : 021302. http://dx.doi.org/10.1063/5.0084554.

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Photoredox catalysis has been prominent in many applications, including solar fuels, organic synthesis, and polymer chemistry. Photocatalytic activity directly depends on the photophysical and electrochemical properties of photocatalysts in both the ground state and excited state. Controlling those properties, therefore, is imperative to achieve the desired photocatalytic activity. Redox potential is one important factor that impacts both the thermodynamic and kinetic aspects of key elementary steps in photoredox catalysis. In many challenging reactions in organic synthesis, high redox potentials of the substrates hamper the reaction, leading to slow conversion. Thus, the development of photocatalysts with extreme redox potentials, accompanied by potent reducing or oxidizing power, is required to execute high-yielding thermodynamically demanding reactions. In this review, we will introduce strategies for accessing extreme redox potentials in photocatalytic transformations. These include molecular design strategies for preparing photosensitizers that are exceptionally strong ground-state or excited-state reductants or oxidants, highlighting both organic and metal-based photosensitizers. We also outline methodological approaches for accessing extreme redox potentials, using two-photon activation, or combined electrochemical/photochemical strategies to generate potent redox reagents from precursors that have milder potentials.
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Vlcek, A. A., Elaine S. Dodsworth, William J. Pietro et A. B. P. Lever. « Excited State Redox Potentials of Ruthenium Diimine Complexes ; Correlations with Ground State Redox Potentials and Ligand Parameters ». Inorganic Chemistry 34, no 7 (mars 1995) : 1906–13. http://dx.doi.org/10.1021/ic00111a043.

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Bednářová, Eva, Logan R. Beck, Tomislav Rovis, Samantha L. Goldschmid, Katherine Xie, Nicholas E. S. Tay, Benjamin D. Ravetz, Jun Li et Candice L. Joe. « Tuning the Electrochemical and Photophysical Properties of Osmium-Based Photoredox Catalysts ». Synlett 33, no 03 (14 janvier 2022) : 247–58. http://dx.doi.org/10.1055/s-0041-1737792.

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AbstractThe use of low-energy deep-red (DR) and near-infrared (NIR) light to excite chromophores enables catalysis to ensue across barriers such as materials and tissues. Herein, we report the detailed photophysical characterization of a library of OsII polypyridyl photosensitizers that absorb low-energy light. By tuning ligand scaffold and electron density, we access a range of synthetically useful excited state energies and redox potentials.1 Introduction1.1 Scope1.2 Measuring Ground-State Redox Potentials1.3 Measuring Photophysical Properties1.4 Synthesis of Osmium Complexes2 Properties of Osmium Complexes2.1 Redox Potentials of Os(L)2-Type Complexes2.2 Redox Potentials of Os(L)3-Type Complexes2.3 UV/Vis Absorption and Emission Spectroscopy3 Conclusions
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Medina, Edinson, et Balazs Pinter. « A DFT Study on the Redox Active Behavior of Carbene and Pyridine Ligands in the Oxidative and Reductive Quenching Cycles of Ruthenium Photoredox Catalysts ». Catalysts 10, no 1 (6 janvier 2020) : 80. http://dx.doi.org/10.3390/catal10010080.

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In this study, a detailed look at the electronic structure changes induced by photon absorption and of the succeeding redox events of the oxidative and reductive quenching cycles of ruthenium–carbene and ruthenium–pyridine photoredox catalysts is provided through an arsenal of density functional theory-based techniques including electron density difference Δρ(r) maps, spin-density distributions, and the non-covalent interaction analysis. We introduced an efficient computational protocol to obtain accurate equilibrium structures and ground-state reduction potentials for these types of complexes, substantiated via a direct comparison to empirical X-ray structures and cyclic voltammetry measurements, respectively. Moreover, we demonstrated the utility of a hitherto unexplored approach to compute excited-state redox potentials based on the Gibbs free energy of the triplet metal-to-ligand charge transfer state (3MLCT). The analyzed Δρ(r) maps revealed the characteristic features of, for example, metal- and ligand-centered reductions and oxidations in both ground and excited states and MLCT processes, disclosing the active participation of carbene ligands in the redox events of homoleptic systems. Beyond analyzing ligand–ligand non-covalent interactions and redox-active behaviors of carbene and pyridine ligands side by side, the effect of such groups on the kinetics of 3MLCT to 3MC transition was scrutinized.
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Hammond, Timothy G., Patricia L. Allen et Holly H. Birdsall. « Validation of Assays for Reactive Oxygen Species and Glutathione in Saccharomyces cerevisiae during Microgravity Simulation ». Gravitational and Space Research 3, no 2 (1 décembre 2015) : 42–53. http://dx.doi.org/10.2478/gsr-2015-0010.

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ABSTRACT The effects of spaceflight on yeast have high concordance with agents that induce a very low intracellular redox state and induce a massive efflux of glutathione. These results raise important issues. Can the reduced redox state during spaceflight be reproduced and modulated in ground-based simulations? Will this allow definition of unique drug pathways as a low redox potential state mirrors the electrophilic properties of mitochondria where many drugs are metabolized? Unfortunately, assays for redox status and its major cellular determinant—glutathione—are diverse and often cell-type-specific. Currently, an accepted redox probe set for yeast studies is not available. This paper validates fluorescent probes for glutathione and reactive oxygen status in yeast to support mechanistic studies of microgravity and drug metabolism. The plethora of fluorescent reagents for reactive oxygen species and glutathione makes head-to-head comparisons of all the alternatives impractical. These reagents measure the physiological milieu of reactive oxygen species and diverse thiols, rather than specific individual molecules. We report that in yeast, monochlorobimane (mBCL) and 2’,7’-dichlorodihydrofluorescein diacetate (DC-FDA) are suitable for fluorometric and flow cytometry studies of glutathione and reactive oxygen species, respectively. Both dyes have low background fluorescence, predictable loading, good retention, and are not acutely toxic to Saccharomyces cerevisiae. Both dyes show concordance with other fluorescent and biochemical assays of reactive oxygen species.
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Bourotte, Christine, Reginaldo Bertolo, Marta Almodovar et Ricardo Hirata. « Natural occurrence of hexavalent chromium in a sedimentary aquifer in Urânia, State of São Paulo, Brazil ». Anais da Academia Brasileira de Ciências 81, no 2 (juin 2009) : 227–42. http://dx.doi.org/10.1590/s0001-37652009000200009.

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Anomalous concentrations of hexavalent chromium have been detected in ground-water of the Adamantina Aquifer inat least 54 municipalities located in the northwestern region of the State of São Paulo, southeast Brazil, occasionallyexceeding the permitted limit for human consumption (0.05 mg.L-1). An investigation was conducted in the municipality of Urânia, where the highest concentrations of chromium were detected regionally. It was defined that the originof this contamination is natural, since high concentrations of chromium were detected in aquifer sandstones (averageof 221 ppm) and also in pyroxenes (6000 ppm), one of the main heavy minerals found in the sediments. Besides, noother possible diffuse or point sources of contamination were observed in the study area. Stratification of ground-waterquality was observed and the highest concentrations of Cr6+ were detected at the base of the aquifer (0.12 mg.L-1),where ground-water shows elevated values for redox potential (472.5 mV) and pH (8.61). The origin of Cr6+ in water may be associated with the weathering of pyroxene (augite), followed by the oxidation of Cr3+ by manganese oxides. The highest concentrations of Cr6+ are probably related to desorption reactions, due to the anomalous alkaline pHfound in ground-water at the base of the aquifer.
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Creutz, Carol, et Mei H. Chou. « Solvent Dependence of the Reduction Potential of Ground- and Excited-State Redox Couples : trans- Dioxo(1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane)osmium(VI/V) ». Inorganic Chemistry 33, no 14 (juillet 1994) : 3199–200. http://dx.doi.org/10.1021/ic00092a033.

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Bumpus, Peter B., et Sarah E. Kruse. « Self-potential monitoring for hydrologic investigations in urban covered-karst terrain ». GEOPHYSICS 79, no 6 (1 novembre 2014) : B231—B242. http://dx.doi.org/10.1190/geo2013-0354.1.

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In the covered karst of west-central Florida, USA, sinkholes (sandy collapse conduits) provide locally concentrated recharge to underlying aquifers. For water management, it would be beneficial to understand the rates at which collapse conduits recharge an underlying aquifer. Self-potential (SP) monitoring has promise as a noninvasive, relatively low-cost method for assessing temporal variability in flow. Previous studies suggested that negative SP anomalies over collapse conduits correspond to downward-flowing groundwater; however, before SP surveys can be reliable indicators of conduit flow, SP from ET, soil conductivity changes, redox, electrode effects, and cultural noise must be better understood. A year of continuous SP monitoring with two grids of approximately 15 Pb/PbCl/KCl nonpolarizing electrodes each was combined with high-resolution ground-penetrating radar surveys and intermittent water table monitoring over two small covered-karst conduits in Tampa, Florida, USA. Although variations in SP resulting from changes in cultural noise, soil conductivity, ET, redox, and rainfall were evident, separate and unrelated positive and negative SP anomalies episodically manifested over conduits, which suggested that conduit flow could be dynamic, not static. Three flow regimes in conduits were postulated: conduit permeability higher than in surrounding surficial sediments, conduit permeability lower than in surrounding surface sediments, conduit permeability matched surrounding surface sediments. Numerical steady-state 2D simulations in Comsol created the three postulated flow regimes and revealed that a different SP polarity could result from different rates of flow: positive SP corresponded to higher permeability conduits, negative SP corresponded to lower permeability conduits, no or minimal SP appeared when conduits and surrounding sediments had equal permeability. In these models, downward flow was not responsible for generating negative SP. To assess the hydrology of a conduit, it appears that SP should be monitored continuously. Further monitoring of field sites with hydrologic sensors is needed.
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Yang, Jing, John H. Enemark et Martin L. Kirk. « Metal–Dithiolene Bonding Contributions to Pyranopterin Molybdenum Enzyme Reactivity ». Inorganics 8, no 3 (5 mars 2020) : 19. http://dx.doi.org/10.3390/inorganics8030019.

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Here we highlight past work on metal–dithiolene interactions and how the unique electronic structure of the metal–dithiolene unit contributes to both the oxidative and reductive half reactions in pyranopterin molybdenum and tungsten enzymes. The metallodithiolene electronic structures detailed here were interrogated using multiple ground and excited state spectroscopic probes on the enzymes and their small molecule analogs. The spectroscopic results have been interpreted in the context of bonding and spectroscopic calculations, and the pseudo-Jahn–Teller effect. The dithiolene is a unique ligand with respect to its redox active nature, electronic synergy with the pyranopterin component of the molybdenum cofactor, and the ability to undergo chelate ring distortions that control covalency, reduction potential, and reactivity in pyranopterin molybdenum and tungsten enzymes.
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Karipidis, Paraskevas, Athanassios C. Tsipis et Constantinos A. Tsipis. « Density Functional Study of the Electronic Structure and Related Properties of Pt(NO)/Pt(NO2) Redox Couples ». Collection of Czechoslovak Chemical Communications 68, no 3 (2003) : 423–46. http://dx.doi.org/10.1135/cccc20030423.

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Density functional calculations at the B3LYP level of theory, using the SDD basis set, provide satisfactory description of geometric, energetic, electronic and spectroscopic properties of the Pt(NO)/Pt(NO2) redox couple. The neutral Pt(NO) species adopts a bent 2A' ground state, while the cationic [Pt(NO)]+ species adopts a linear 1Σ+ ground state. The B3LYP/SDD- predicted Pt-N bond lengths are 2.016 and 1.777 Å for Pt(NO) (2A') and [Pt(NO)]+ (1Σ+), respectively, while the ∠Pt-N-O bent angle for [Pt(NO)] (2A') is 119.6°. On the other hand, the anionic [Pt(NO)]- species adopts the bent 1A' ground state with a Pt-N bond length of 1.867 Å and a ∠Pt-N-O bent angle of 122.5°. The computed binding energies of the NO, NO+ and NO- ligands with Pt(0) were found to be 29.9 (32.8), 69.9 (78.4) and 127.4 (128.7) kcal/mol at the B3LYP/SDD and CCSD(T)/SDD (numbers in parentheses) levels of theory, respectively. Moreover, the structure of the [Pt(NO2)]+ component of the Pt(NO)/Pt(NO2) redox couple and its transformation to [Pt(NO)]+ upon reaction with CO was analysed in the framework of the DFT theory. The coordination of the CO ligand to [Pt(NO2)]+ affords the cationic mixed-ligand [Pt(CO)(NO2)]+ complex, which is stabilized by 66.6 (60.5) kcal/mol, with respect to the separated [Pt(NO2)]+ and CO in their ground states. The O-transfer reaction from the coordinated NO2 to the coordinated CO ligands in the presence of the [Pt(NO2)]+ species corresponds to an exothermic process; the heat of the reaction (∆RH) is -85.2 (-80.5) kcal/mol and the activation barrier amounts to 27.7 (33.0) kcal/mol. Finally, the equilibrium structures of selected stationary points related to the transformation of NO to NO2 ligand located on the potential energy surfaces of the [Pt(NO),O2], [Pt(NO)+,O2], and [Pt(NO)-,O2] systems were analysed in the framework of the DFT theory. The computed interaction energies of O2 with Pt(NO), [Pt(NO)]+ and [Pt(NO)]- species were found to be 106.9 (105.3), 49.2 (48.4) and 26.9 (26.5) kcal/mol, respectively. The O2 ligand is coordinated to the Pt central atom in an end-on mode for [Pt(NO),O2] and [Pt(NO)-,O2] systems and in a side-on mode for the [Pt(NO)+,O2] system. The transformation of NO to NO2 in [Pt(NO)]- species upon reaction with dioxygen corresponds to an exothermic process; the heat of the reaction (∆RH) is -60.6 (-55.8) kcal/mol, while the activation barrier amounts to 35.5 (30.2) kcal/mol. Calculated structures, relative stability and bonding properties of all stationary points are discussed with respect to computed electronic and spectroscopic properties, such as charge density distribution and harmonic vibrational frequencies.
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YANG, SUNG IK, JYOTI SETH, JON-PAUL STRACHAN, STEVE GENTEMANN, DONGHO KIM, DEWEY HOLTEN, JONATHAN S. LINDSEY et DAVID F. BOCIAN. « Ground and Excited State Electronic Properties of Halogenated Tetraarylporphyrins : Tuning the Building Blocks for Porphyrin-based Photonic Devices ». Journal of Porphyrins and Phthalocyanines 03, no 02 (février 1999) : 117–47. http://dx.doi.org/10.1002/(sici)1099-1409(199902)3:2<117 ::aid-jpp110>3.0.co;2-x.

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The rational design of molecular photonic devices relies on the ability to select components with predictable electronic structure, excited state lifetimes and redox chemistry. Electronic communication in multiporphyrin arrays depends critically on the relative energies and electron density distributions of the frontier molecular orbitals, especially the energetically close highest occupied molecular orbitals (a2u and a1u). To explore how these ground and excited state properties can be modulated, we have synthesized and characterized 40 free base ( Fb ), magnesium and zinc tetraarylporphyrins. The porphyrins bear meso-substituents with the following substitution patterns: (1) four identical substituents (phenyl, o-chlorophenyl, p-chlorophenyl, o,o'-difluorophenyl, pentafluorophenyl, mesityl); (2) one, two, three or four o,o'-dichlorophenyl substituents; (3) one p-ethynylphenyl group and three mesityl or pentafluorophenyl groups; (4) one p-ethynyl-o,o″-dichlorophenyl or p-ethynyl-o,o″-dimethylphenyl and three phenyl groups. For each neutral complex the ground state electronic properties were investigated using electrochemical methods and optical absorption spectroscopy. Similarly the absorption, emission, and relaxation properties of the lowest singlet excited state were probed by time-resolved absorption and fluorescence methods. Each oxidized complex was investigated by static absorption and liquid and frozen solution EPR spectroscopy. The collective results of these investigations have provided insights into the direct (orbital overlap) and indirect (inductive/conjugative) mechanisms by which halogenated phenyl rings influence the static and dynamic electronic properties of neutral and oxidized porphyrinic chromophores. Three key findings are as follows. (1) The effective electron-withdrawing strength of halogenated phenyl rings required to reverse the ordering of the a2u and a1u HOMOs in Mg versus Zn tetraarylporphyrins has been elucidated. (2) Appropriate halogenation can significantly increase the excited state lifetime of a Zn porphyrin relative to the unsubstituted complex. (3) Halogenation can be used to modulate redox potentials in a manner that complements the enhancement of other electronic properties. The insights gained from study of this library of porphyrins provide a foundation for tuning the electronic properties of monomeric porphyrins as building blocks for multichromophoric assemblies in optoelectronics and other applications.
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Njogu, Rachael, Peter Fodran, Yuxi Tian, Lydia Njenga, David Kariuki, Amir Yusuf, Ivan Scheblykin, Ola Wendt et Carl-Johan Wallentin. « Electronically Divergent Triscyclometalated Iridium(III) 2-(1-naphthyl)pyridine Complexes and Their Application in Three-Component Methoxytrifluoromethylation of Styrene ». Synlett 30, no 07 (8 février 2019) : 792–98. http://dx.doi.org/10.1055/s-0037-1611716.

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A systematic study of the photophysical and electrochemical properties of triscyclometalated homoleptic iridium(III) complexes based on 2-(1-naphthyl)pyridine (npy) ligands is presented. A systematic investigation of ligand substitution patterns showed an influence on the lifetime of the excited state, with slight changes in the absorption and emission spectral features. Specifically, the emission lifetime of a complex of an npy ligand substituted with a strongly electron-withdrawing trifluoromethyl group was longer than that of the corresponding complex with the electronically nonperturbed ligand (3.7 μs versus 1.5 μs). Electronically complementary ligands and complexes with ­orthogonal configurations showed slightly shorter excited state lifetimes compared with unsubstituted npy (1.4–3.0 μs). All complexes displayed reversible or quasireversible redox-couple processes, with the complex of the trifluoromethylated ligand showing the highest ground-state oxidation potential E1/2 ox [Ir(III)/Ir(IV) = 0.95 V vs. SCE in CH2Cl2]. This study showed that these complexes can be used as efficient photoredox catalysts, as demonstrated by their application in a regioselective methoxytrifluoromethylation in which the npy complexes showed equal or better performance compared with the archetypical photo­redox catalyst tris[2-phenylpyridinato]iridium(III).
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Grover, Nitika, Pinki Rathi et Muniappan Sankar. « Spectral investigations of meso-tetraalkylporphyrin-fullerene host–guest complexes ». Journal of Porphyrins and Phthalocyanines 19, no 09 (septembre 2015) : 997–1006. http://dx.doi.org/10.1142/s1088424615500716.

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Meso-tetraalkylporphyrins and their Zn(II) complexes were synthesized and characterized by various spectroscopic techniques. Single crystal X-ray structure of meso-tetrapropylporphyrin (3) revealed the orientation of alkyl chains and planar conformation of porphyrin macrocycle. Spectroscopic, photophysical and electrochemical redox properties of self-assembled donor–acceptor dyads formed by meso-tetraalkylporphyrins and fullerene C 60 were investigated. These studies revealed 1:1 supramolecular dyad formation between the electron donor porphyrins and the electron acceptor, fullerene entities. The determined association constants (K) follow the order: H2TMeP (1) > H2TEtP (2) > H2TPrP (3) > H2THexP > H2TPP . The effect of alkyl chain length on porphyrin-fullerene complexation was investigated. The redox behavior of self-assembled dyads was investigated in PhCN containing 0.1 M TBAPF6 as supporting electrolyte. The oxidation potentials of dyads are positively shifted (20–100 mV) as compared to corresponding meso-tetraalkylporphyrins indicating the supramolecular interactions between the constituents in the ground state. The geometric and electronic structure of 1: C 60 was probed by DFT calculations which suggested the possibility of charge transfer from meso-tetraalkylporphyrin to fullerene C 60.
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Jaszczyński, Jacek. « The relationship between dissolved organic carbon and hydro-climatic factors in peat-muck soil ». Journal of Water and Land Development 24, no 1 (1 mars 2015) : 27–33. http://dx.doi.org/10.1515/jwld-2015-0004.

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Abstract The object of this study was the concentration of dissolved organic carbon (DOC) in soil solution related to groundwater table, soil temperature, moisture, redox potential and intensive storm rain and their changes during ten years (2001–2010). The studies were localized in drained and agriculturally used Kuwasy Mire situated in the middle basin of the Biebrza River, north-eastern Poland. The study site was situated on a low peat soil managed as intensively used grassland. The soil was recognized as peat-muck in the second stage of the mucking process. DOC concentration was determined by means of the flow colorimetric method using the Skalar equipment. Mean in the whole study period DOC concentration in soil solution was 72 mg·dm−3. A significant positive correlation was observed between DOC concentration and soil temperature at 30 cm depth. The highest DOC concentrations were observed from July to October accompanied by the lowest ground water level. The DOC concentration in soil solution showed also a significant correlation with soil redox potential at 20 cm depth – a border between muck and peat layers. This layer is potentially most active with respect to biochemical transformation. There was no relationship between DOC concentration and soil moisture. However, the influence of torrential rains on the intensity of DOC removal was demonstrated in this study.
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Re, Viviana, Myat Mon Thin, Chiara Tringali, Mya Mya, Enrico Destefanis et Elisa Sacchi. « Laying the Groundwork for Raising Awareness on Water Related Issues with a Socio-Hydrogeological Approach : The Inle Lake Case Study (Southern Shan State, Myanmar) ». Water 13, no 17 (4 septembre 2021) : 2434. http://dx.doi.org/10.3390/w13172434.

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Translating scientific findings into concrete action for (ground)water protection should be fundamental component of any hydrogeological and hydrogeochemical assessment, thus ensuring that scientific outcomes have a positive impact in the real world. To this purpose, understanding the water-related issues and the perceived criticalities by the water users is an asset, especially for earth scientists who are often the first contact with local communities during in situ measurements. By presenting the results of a socio-hydrogeological assessment in the Inle Lake area, this paper aims at demonstrating the feasibility and added value of this approach. In conjunction with groundwater sampling, public engagement activities were conducted by administering semi-structured interviews at a household level in each monitoring site. Hydrogeochemical data show that groundwater is characterized by an elevated hardness and by the presence of trace metals in solution due to the low redox potential. The work provides suggestions on how to translate the hydrogeochemical information associated to (i) the impact of climate change on water supply and availability, and (ii) the presence of geogenic groundwater contamination (Fe, Mn, As) into accessible information for local communities and water users’ associations. Sharing knowledge and promoting capacity building would also help to assess the reasons for the discrepancy between self-reported perception of groundwater quality (e.g., hardness) and analytical results.
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Milanesio, M. Elisa, Miguel Gervaldo, Luis A. Otero, Leonides Sereno, Juana J. Silber et Edgardo N. Durantini. « Synthesis of a diporphyrin dyad bearing electron-donor and electron-withdrawing substituents with potential use in the spectral sensitization of semiconductor solar cells ». Journal of Porphyrins and Phthalocyanines 07, no 01 (janvier 2003) : 42–51. http://dx.doi.org/10.1142/s1088424603000070.

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A new dyad 9( ZnP - P ) has been synthesized linking 5,15-bis(4-carboxyphenyl)-10,20-bis(4-nitrophenyl) porphyrin 4( P ) and Zn(II) 5-(4-aminophenyl)-10,15,20-tris(4-methoxylphenyl) porphyrin 8 (ZnP) by an amide bond. The structural moieties of dyad 9( ZnP-P ) present both different singlet state energy and redox properties. Dyad 9 was designed to improve the intramolecular electron transfer capacity. The ZnP moiety bears electron-donating methoxy groups and a zinc ion, while the other porphyrin structure, P , is substituted by electron-withdrawing nitro groups. On the other hand, structure P bears a carboxylic acid group, which is able to benefit from the orientation of dyad 9 adsorbed on the SnO 2 electrode. Absorption spectroscopic studies indicated only a very weak interaction between the chromophores in the ground state. The fluorescence analysis shows that both porphyrin moieties in dyad 9 are strongly quenched and that the quenching increases in a polar solvent. The ZnP moiety acts like an antenna for porphyrin P , but, singlet-singlet energy transfer is not complete. Thermodynamically, dyad 9 presents a high capacity to form the photoinduced charge-separated state, ZnP ·+- P ·-. Dyad 9 sensitizes the SnO 2 electrode and the photocurrent action spectrum closely matches the absorption spectrum, which confirms that light absorption by dyad is the initial step in the charge transfer mechanism. The photocurrent efficiency of dyad 9 is considerably higher than those of porphyrin monomers used as models of ZnP and P structures. Two processes may be contributing to enhance the charge injection efficiency in dyad 9; one involves an antenna effect that produces energy transfer from ZnP to P and the other includes electron transfer from the ZnP moiety to the photooxidizable free-base P . This dyad design, with P in direct contact with the substrate through the free carboxylic acid group, is a promising architecture of organic material for spectral sensitization of semiconductor solar cells.
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Farah, Salim F., Robert A. McClelland, Michael R. Peterson et Imre G. Csizmadia. « Molecular structure and relative proton and electron affinities of isomeric nitroimidazoles ». Canadian Journal of Chemistry 67, no 10 (1 octobre 1989) : 1666–71. http://dx.doi.org/10.1139/v89-255.

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The isomeric 2-nitro, 4-nitro, and 5-nitroimidazoles have been studied in their planar ground state, C—NO2 rotational transition state, 3-H protonated conjugate acid and radical anion forms, with abinitio computations at the split-valence 3-21G basis set level. The stabilities of the parent compounds follow the order 5-NO2 ~ 4-NO2 > 2-NO2. In solution 4-nitro is more stable than 5-nitro; the calculations suggest that this is a solvation effect, since the 4-nitro isomer has a considerably higher dipole moment. Barriers for nitro group rotation range from 10 to 16 kcal/mol. However, the relative change in dipole moment during the rotation is small, suggesting that dipole moments of nitroimidazoles are determined mainly by inductive effects, with resonance interactions being relatively unimportant. This conclusion is supported by calculations of molecular electrostatic potentials of the planar and rotated forms. Electron affinities follow the order [Formula: see text], closely matching the order of biological effectiveness of nitroimidazole radiosensitizers. This is consistent with suggestions that the "nitro:nitro radical anion" redox cycle is an important determinant of biological activity. Keywords: nitroimidazole, abinitio computation, rotational barrier, proton affinity, electron affinity.
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19

Oprea, Corneliu I., Petre Panait, Zahraa M. Essam, Reda M. Abd El-Aal et Mihai A. Gîrțu. « Photoexcitation Processes in Oligomethine Cyanine Dyes for Dye-Sensitized Solar Cells—Synthesis and Computational Study ». Nanomaterials 10, no 4 (2 avril 2020) : 662. http://dx.doi.org/10.3390/nano10040662.

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We report density functional theory (DFT) calculations of three newly synthesized oligomethine cyanine-based dyes as potential TiO2-sensitizers in dye-sensitized solar cells. The three dyes have π-symmetry and the same acceptor side, terminating in the carboxylic anchor, but they differ through the π-bridge and the donor groups. We perform DFT and time-dependent DFT studies and present the electronic structure and optical properties of the dyes alone as well as adsorbed to the TiO2 nanocluster, to provide some predictions on the photovoltaic performance of the system. We analyze theoretically the factors that can influence the short circuit current and the open circuit voltage of the dye-sensitized solar cells. We examine the matching of the absorption spectra of the dye and dye-nanocluster system with the solar irradiation spectrum. We display the energy level diagrams and discuss the alignment between the excited state of the dyes and the conduction band edge of the oxide as well as between the redox level of the electrolyte and the ground state of the dyes. We determine the electron density of the key molecular orbitals and analyze comparatively the electron transfer from the dye to the semiconducting substrate. To put our findings in the right perspective we compare the results of our calculations with those obtained for a coumarin-based dye used in fabricating and testing actual devices, for which experimental data regarding the photovoltaic performance are available.
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Yamada, Atsuo. « (Battery Division Research Award) Structure-Property Relationships : A Journey From LFP to Lithium Metal ». ECS Meeting Abstracts MA2022-02, no 3 (9 octobre 2022) : 209. http://dx.doi.org/10.1149/ma2022-023209mtgabs.

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Conceptual importance of “Matastable Phase Diagram” and “Liquid Madelung Potential” will be demonstrated by picking up some of my mechanism-solving works on LFP and lithium metal. In Li x FePO4, the ground state phase separation and metastable solid solution are energetically competitive, and the solid solution phase is induced in a non-equilibrium electrochemical reaction, playing critical role for fast kinetics. However, there had been no discussion or experimental report of the crystal structure, optical and transport properties of the metastable solid solution phase due to the extreme technical difficulties; the solid-solution phase Li x FePO4 is metastable during electrochemical process and disappears within a few seconds. We overcame this limitation by quenching Li x FePO4 (x = 2/3) at 350 °C to room temperature. This quenched phase remained stable for a couple of weeks, which enabled sufficient time to measure the several intrinsic properties, including polaron-crystallized superstructure, optical properties with emerging inter-valence charge transfer absorption, and enhanced conductivity over 103 in order. Since the Li/Li+ redox potential (E Li/Li+) positions outside of the thermodynamical potential window of the present electrolyte, suppressing side reactions is essential, which can be realized not only by kinetic suppression by SEI but also by thermodynamic stabilization viz. upshift of E Li/Li+. Remarkable improvement of Coulombic efficiency is exemplified in (locally) salt-concentrated electrolyte, where E Li/Li+ largely upshifts over 0.6 V. We revealed that the unusual upshift of E Li/Li+ is primarily dominated by Coulombic energy penalty of Li+ in the electrolytes rather than the simple Nernst equation with extremely high Li+ activity coefficient.[1] Overall energetics was verified and directly quantified by introducing the “liquid Madelung potential (E LM)” analogous to the conventional concept in solid-state science.[1] Namely, Li+ is electrostatically more stabilized by electron-localized solvents, while relatively less stabilized by electron-delocalized larger sized anion, thus decreasing the overall Coulombic energy gain of Li+ under progressive anion coordination.[1] [1] N. Takenaka, S. Ko, A. Kitada, and A. Yamada, submitted (2022) Figure 1
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Sakai, Hayato, Mohammad Gulam Rabbani et Taku Hasobe. « Porphyrin hexamer with a triphenylene core unit : Spectroscopy, electrochemistry and controllable supramolecular formation ». Journal of Porphyrins and Phthalocyanines 15, no 07n08 (juillet 2011) : 639–51. http://dx.doi.org/10.1142/s1088424611003574.

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A series of free-base and zinc porphyrin hexamers, where six porphyrin units are linked to a triphenylene core through amide or ester linkage, was designed and synthesized in an effort to study their spectroscopic and electrochemical properties, and aggregate formation. The distances between triphenylene core and porphyrin moieties are tuned by changing the lengths of spacer alkyl chains. The absorption spectral studies indicates that the porphyrin units in a hexamer behave like monomeric porphyrins, while a strong fluorescence quenching of triphenylene core was observed suggesting the deactivation of the excited state of triphenylene. The redox potentials of porphyrin units in a hexamer were estimated by differential pulse voltammetry (DPV). These values are very similar to those of the corresponding monomer. Consequently, absorption and electrochemical data demonstrate that six porphyrin units of (H2PAC5)6TPh behave like monomers independently in the ground state. The hexamers undergo supramolecular aggregation spontaneously in different fashions based on the solvent systems as well as spacer lengths. Highly ordered and aligned monolayer-based patterns are formed when hexamers are allowed to aggregate from toluene solution onto carbon-coated copper films. In contrast, hexamers undergo aggregation to nanoparticles in toluene/acetonitrile mixed solvent system and the particle sizes increase with increasing the spacer alkyl chain lengths.
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22

Islam, Ashraful, Surya Prakash Singh et Liyuan Han. « Synthesis and Application of New Ruthenium Complexes Containingβ-Diketonato Ligands as Sensitizers for Nanocrystalline TiO2Solar Cells ». International Journal of Photoenergy 2011 (2011) : 1–8. http://dx.doi.org/10.1155/2011/204639.

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Five heteroleptic ruthenium complexes having differentβ-diketonato ligands, [Ru(tctpy)(dppd)(NCS)] (1), [Ru(tctpy)(pd)(NCS)] (2), [Ru(tctpy)(tdd)(NCS)] (3), [Ru(tctpy)(mepd)(NCS)] (4), and [Ru(tctpy)(tmhd)(NCS)] (5), where tctpy = 4,4′,4′′-tricarboxy-2,2′:6′,2′′-terpyridine, pd = pentane-2,4-dione, mepd = 3-methylpentane-2,4-dione, tmhd = 2,2,6,6-tetramethylheptane-3,5-dione, tdd = tridecane-6,8-dione, and dppd = 1,3-diphenylpropane-1,3-dione, were synthesized and characterized. These heteroleptic complexes exhibit a broad metal-to-ligand charge transfer absorption band over the whole visible range extending up to 950 nm. The low-energy absorption bands and theE (Ru3+/2+) oxidation potentials in these complexes could be tuned to about 15 nm and 110 mV, respectively, by choosing appropriateβ-diketonate ligands. Molecular orbital calculation of complex1shows that the HOMO is localized on the NCS ligand and the LUMO is localized on the tctpy ligand, which is anchored to the TiO2nanoparticles. Theβ-diketonato-ruthenium(II)-polypyridyl sensitizers, when anchored to nanocrystalline TiO2films for light to electrical energy conversion in regenerative photoelectrochemical cells, achieve efficient sensitization to TiO2electrodes with increasing activity in the order5<4<3≈2<1. Under standard AM 1.5 sunlight, the complex1yielded a short-circuit photocurrent density of 16.7 mA/cm2, an open-circuit voltage of 0.58 V, and a fill factor of 0.64, corresponding to an overall conversion efficiency of 6.2%. A systematic tuning of HOMO energy level shows that an efficient sensitizer should possess a ground-state redox potential value of >+.53 V versus SCE.
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Cantu, Robert, Habtom B. Gobeze et Francis D’Souza. « Synthesis and photochemical studies of a tris(4-iodophenoxy) subphthalocyaninato boron(III)-fulleropyrrolidine dyad ». Journal of Porphyrins and Phthalocyanines 20, no 08n11 (août 2016) : 987–96. http://dx.doi.org/10.1142/s1088424615500947.

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A subphthalocyanine-fullerene dyad, 1 was newly synthesized through axial functionalization via central boron of subphthalocyanine with [Formula: see text]-hydroxybenzaldehyde, and subsequent dipolar cycloaddition reaction of fullerene. The subphthalocyanine entity was peripherally functionalized with moderately electron rich 4-iodophenoxy substituents to probe their effect on photoinduced processes within the SubPc-C[Formula: see text] dyad. Optical absorbance studies revealed presence of both entities of the dyad while steady-state fluorescence studies revealed quenching of subphthalocyanine emission in the dyad in both nonpolar toluene and polar benzonitrile solvents. Further, redox potentials of the donor and acceptor entities were obtained by differential pulse voltammetry, and energy of different photochemical processes was evaluated. Femtosecond transient absorption studies revealed occurrence of charge separation in the SubPc-C[Formula: see text] dyad either from the 1SubPc* or 1C[Formula: see text]* in both nonpolar and polar solvents. That is, transient peaks in the 665 nm range corresponding to SubPc[Formula: see text] and at 1015 nm corresponding to C[Formula: see text] was possible to spectrally identify. The measured rate of charge separation, [Formula: see text] was found to be ∼7.0 × 10[Formula: see text] s[Formula: see text] irrespective of the solvent. The rate of charge recombination, [Formula: see text] from the decay of the C[Formula: see text] peak was found to be 1.1 × 109 s[Formula: see text] in toluene and 1.3 × 109 s[Formula: see text] in benzonitrile, respectively. The SubPc[Formula: see text]-C[Formula: see text] radical ion-pair populated the low-laying 3SubPc* prior returning to the ground state.
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24

Rooks, Christine, James Kar-Hei Fang, Pål Tore Mørkved, Rui Zhao, Hans Tore Rapp, Joana R. Xavier et Friederike Hoffmann. « Deep-sea sponge grounds as nutrient sinks : denitrification is common in boreo-Arctic sponges ». Biogeosciences 17, no 5 (6 mars 2020) : 1231–45. http://dx.doi.org/10.5194/bg-17-1231-2020.

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Abstract. Sponges are commonly known as general nutrient providers for the marine ecosystem, recycling organic matter into various forms of bioavailable nutrients such as ammonium and nitrate. In this study we challenge this view. We show that nutrient removal through microbial denitrification is a common feature in six cold-water sponge species from boreal and Arctic sponge grounds. Denitrification rates were quantified by incubating sponge tissue sections with 15NO3--amended oxygen-saturated seawater, mimicking conditions in pumping sponges, and de-oxygenated seawater, mimicking non-pumping sponges. It was not possible to detect any rates of anaerobic ammonium oxidation (anammox) using incubations with 15NH4+. Denitrification rates of the different sponge species ranged from below detection to 97 nmol N cm−3 sponge d−1 under oxic conditions, and from 24 to 279 nmol N cm−3 sponge d−1 under anoxic conditions. A positive relationship between the highest potential rates of denitrification (in the absence of oxygen) and the species-specific abundances of nirS and nirK genes encoding nitrite reductase, a key enzyme for denitrification, suggests that the denitrifying community in these sponge species is active and prepared for denitrification. The lack of a lag phase in the linear accumulation of the 15N-labelled N2 gas in any of our tissue incubations is another indicator for an active community of denitrifiers in the investigated sponge species. Low rates for coupled nitrification–denitrification indicate that also under oxic conditions, the nitrate used to fuel denitrification rates was derived rather from the ambient seawater than from sponge nitrification. The lack of nifH genes encoding nitrogenase, the key enzyme for nitrogen fixation, shows that the nitrogen cycle is not closed in the sponge grounds. The denitrified nitrogen, no matter its origin, is then no longer available as a nutrient for the marine ecosystem. These results suggest a high potential denitrification capacity of deep-sea sponge grounds based on typical sponge biomass on boreal and Arctic sponge grounds, with areal denitrification rates of 0.6 mmol N m−2 d−1 assuming non-pumping sponges and still 0.3 mmol N m−2 d−1 assuming pumping sponges. This is well within the range of denitrification rates of continental shelf sediments. Anthropogenic impact and global change processes affecting the sponge redox state may thus lead to deep-sea sponge grounds changing their role in marine ecosystem from being mainly nutrient sources to becoming mainly nutrient sinks.
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Melnychuk, S. S., et G. G. Trokhymenko. « Peculiarities of migration and accumulation of heavy metals in the system «ground-plant» by the example of the National natural park «Beloberezhye Svyatoslava» ». Ecology and Noospherology 28, no 3-4 (15 mars 2017) : 45–54. http://dx.doi.org/10.15421/031715.

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Heavy metals like ekopolyudanty have a high capacity for bioaccumulation, toxicity and significant mobility in the environment. Since the bulk of the land is plants, it is important to identify the processes of migration and accumulation of heavy metals in them. But keep in mind that the level of heavy metal accumulation in plants of different taxonomic groups are not the same. Cumulative capacity of plants depends on many factors: the type of soil, humidity, altitude, meteorological characteristics of the region and landscape, and more. It should be noted that the migration of heavy metals from soil to plants depends on the concentration of mobile forms in soil. Once the soil heavy metals are constantly migrating, moving to some form of chemical compounds. Although soils are characterized by resistance to chemical contamination due to its ability to accumulate and neutralize ecotoxicants. But it is significant accumulation in soil heavy metals leads to lower pH of the soil and destroys the soil-absorbing complex. The object of study in this paper selected park «Biloberezhzhya Svyatoslav» which Presidential Decree Ukraine in 2009 was granted the status of National Park «Biloberezhzhya Svyatoslav», so the park is virtually unexplored. The aim is to study the phenomenon of bioaccumulation of heavy metals in soil and plants cover various ecotheitons and their influence on the processes of human transformation in these florocomplexes. For the past 10 years the National Park is undergoing significant anthropogenic pressure on transport, recreation, hotels and aggressive recreational activities. So one of the important aspects of solving the problem is to provide control and accounting of vehicles, which enters the territory of spit and emission monitoring (especially heavy metals) which makes transport and monitoring of soil and vegetation that will characterize the current state of ecosystems National Park «Biloberezhzhya Svyatoslav» and anticipate negative processes that occur in ecosystems of different levels. To study the vegetation of the National Park «Biloberezhzhya Svyatoslav» that is able to accumulate heavy metals in significant quantities were selected samples of the dominant plant species in various microflorocomplexes. For more detailed specifications the transformation of these substances in the soil and their translocation in plants and soil samples were taken at a depth of 20 cm. In the study the accumulation of heavy metals in soils contributes primarily low acidity (neutral and slightly alkaline pH) soil horizons in gleying cuts low values ​​of redox potential and high content of amorphous hydroxides Fe. The remaining soil parameters – a low content of organic matter, light texture, low cation exchange capacity value (ECO) soil absorbing complex, a high redox potential – are unfavorable factors for the accumulation of heavy metals in soils. Analysis of mobile forms of heavy metals in the soil studied florocomplexes showed that the majority of indicators does not exceed the MCL. This minimum figure for cadmium Li, Aln, Qbp, apparently caused by acidity (pH) of the soil. Overall indicators of cadmium in florocomplexes studied ranged from 0 to 0.7 mg / kg. The maximum amount of cadmium in Mar (0,6 mg / kg), Rap (0,7 mg / kg) and only they exceed the MCL level that caused considerable indirect influence, since these florocomplexes heavy metals fall on the Dnieper River from cities and businesses located upstream. Indicators of copper in florocomplexes fluctuate within 0.5–4.0 mg / kg, thus exceeding the MCL only Mar (3,2 mg / kg), Rap (4,0 mg / kg), which reduces the enzymatic activity of soil. Similar figures have nickel 0.5–5.0 mg / kg, exceeding the MCL in Mar and Rap. Number of lead in the top layer of soil depends not only on the human impact, but also from iron oxides, which can form complexes with Lead. As he studied florokompleksah ranges from 0.8–3.8 mg / kg, and not exceeding the MCL. The maximum of the number of zinc – 2.5–7.1 mg / kg, which is caused by the structure of the parent rock, characterized by a large number of iron oxides and pH in which it is possible absorption of lead hydroxide. However, no figure does not exceed the MCL. So low rates of bioaccumulation factors indicate a low level of accumulation of heavy metals in soils of ecotheitons of National Park «Biloberezhzhya Svyatoslav», i.e. minor processes of human impacts on natural ecosystems. Sandy soils are characterized by low absorptive capacity, and a weak hold heavy metals except molybdenum and selenium. Because plants easily adsorb them, some of them even in very small concentrations have a toxic effect. So exceeded MPC Dominant Mar, Rap – Zoctera marina L. and Ruppia cirrhoza (Petagma) Grande. indicate intense indirect human impact on water florocomplexes that are part of the National Park «Biloberezhzhya Svyatoslav» because these florocomplexes heavy metals fall on the Dnieper River from cities and businesses that are located upstream. The lowest coefficients of accumulation in the soil and in plants characteristic of Hy and Lst, which is caused by geographical barriers that protect them from human activity. For values of absorption coefficients biotic can conclude not only the role of individual species of plants and vegetation in the whole cycle of elements in the ecosystem, but also the ecosystem’s ability to cleanse itself. In florocomplexes of National Park «Biloberezhzhya Svyatoslav» is obviously particularly important role in the self-cleaning from heavy metals play the genera Phragmites Trin. ex Steud. and Zoctera L., both because of the high intensity of the absorption element (Zoctera L.), and because of the high biomass of these species in communities (Phragmites Trin. ex Steud.). Among the analyzed dominant species, growing on uncontaminated and contaminated areas revealed two species hiperakumulyatory heavy metals – Phragmites australis (Cav.) Trin. ex Steud and Zoctera marina L. addition to those of the common species that accumulate significant biomass and have relatively high rates of accumulation of Cd, Zn, Pb, – a species: Grindelia squarrosa L., Salicornia prostrata Pall., Poa angustifolia L., which can be recommended as objects of future field experiments.
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Zagal, Jose H., Federico Tasca et Ingrid Ponce. « (Keynote) Interpretation of Oxygen Reduction Activity Volcano Correlations for MN4 Molecular Catalysts Compared to Those for Metallic Electrodes ». ECS Meeting Abstracts MA2022-01, no 49 (7 juillet 2022) : 2057. http://dx.doi.org/10.1149/ma2022-01492057mtgabs.

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A classical well-known reactivity index in electrocatalysis is the binding energy of key intermediates to the active sites. For example, this is well documented for the catalytic activity of metal electrodes for the oxygen reduction reaction (ORR)[1], alloys and metal oxides and less studied for molecular catalysts [2]. The activity at constant potential (log(i)E) plotted versus the M-O2 binding energy has the shape of a volcano. This is well documented in several papers, especially by the group of Norksov for metallic electrodes [1] and can be applied to many electrochemical reactions. This has been extended to MN4 molecular catalysts. In contrast to metallic electrodes MN4 molecular catalysts have discrete energy levels and the active site is the central metal, surrounded by an organic ligand with an MN4 central moiety. Essentially one of the key intermediates is the binding of the reacting O2 molecule to the active sites at the rate determining step as: [MN4]ad + O2(aq) + e- ↔ [RMN4O2 -]ad where MN4 is a surface confined macrocyclic complex or a pyrolyzed catalysts bearing a MN4 active moiety embedded in a graphene or graphitic structure. As the ORR reaction involves the transfer of several electrons ( 2, 2+2 or 4 electrons), several adsorbed intermediates can be involved. If the controlling step is the first step, it is expected that for the binding step when DGad = 0 a maximum activity should be observed and the partial coverage of adsorbed intermediate is = 0.5. On thermodynamic ground this corresponds to a thermoneutral condition for the best catalyst. In this work we have tested this hypothesis by studying ORR in alkaline media using several iron porphyrins and iron phthalocyanines as catalysts immobilized on graphite and carbon nanotubes. The trends in reactivity versus the Fe(III)/(II) redox potential for ORR describe a typical volcano correlation. However if the currents are divided by the θFe(II), the fraction of active sites calculated at E=-0.24 V vs SCE using the Nernst equation, log(i/ θFe(II),)E vs. E°Fe(III)/(II) gives a straight line of slope -0.120V/decade. The maximum corresponds to θFe(II) = 0.5 and occurs at a potential close to that used for comparing the activities. A similar behaviour is observed for the oxidation of hydrazine but the continuation of the straight line is observed at potentials more positive than that of the maximum. Again the maximum is observed at the potential chosen for comparison. Those catalysts having Eº’ Fe(III)/(II) >> θFe(II) higher than -0.56V (for hydrazine oxidation) are in the Fe(III) state as predicted by the Nernst equation. That oxidation state Fe(III) is inactive for both reactions studied as OH- ions are strongly bound to Fe(III), especially in alkaline media. So the falling of the activities in the strong binding side of the volcano can be attributed preferentially to a gradual decline in the number of Fe(II) active sites and not to gradual decrease of the fraction (1-θ ) of empty or available active sites due to occupancy by intermediates. Schmickler and Santos [3] have shown that some volcano correlations for HER on metals that are in an oxidized form, and then inactive for this reason. We conclude that even though there are similarities between the volcano correlations for metallic and molecular catalysts, there some differences in the interpretation of the activity maximum that might not correspond to a thermoneutral condition. Acknowledgements: This work was supported by ANID, Anillo Project ACT 192175 and Fondecyt, Project 1181037 References: [1] J.K. Norskov et al., J Catal.,328 (2015) 35 [2] J.H. Zagal & M.T.M.Koper, Angew. Chem. Int Ed.,, 128 (2016) 14726 [4] [3] J.H. Zagal, P. Atanassov, S. Specchia, Current Op. Electrochem. 27 (2021), 100687, E. Santos, W. Schmickler et al. Beilstein J. Nanotech.., 5 (2014) 846.
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Bitto, Herbert, Dean R. Guyer, William F. Polik et C. Bradley Moore. « Dissociation on ground-state potential-energy surfaces ». Faraday Discussions of the Chemical Society 82 (1986) : 149. http://dx.doi.org/10.1039/dc9868200149.

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Jensen, Hans Joergen A., Poul Joergensen et Trygve Helgaker. « Ground-state potential energy surface of diazene ». Journal of the American Chemical Society 109, no 10 (mai 1987) : 2895–901. http://dx.doi.org/10.1021/ja00244a007.

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Šurkus, A. « Ground-state potential energy function of SiCl+ ». Spectrochimica Acta Part A : Molecular and Biomolecular Spectroscopy 60, no 8-9 (juillet 2004) : 2185–87. http://dx.doi.org/10.1016/j.saa.2003.09.016.

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Bunker, P. R., Ota Bludsky, Per Jensen, S. S. Wesolowski, T. J. Van Huis, Y. Yamaguchi et H. F. Schaefer. « The H2O++ Ground State Potential Energy Surface ». Journal of Molecular Spectroscopy 198, no 2 (décembre 1999) : 371–75. http://dx.doi.org/10.1006/jmsp.1999.7970.

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31

Poznanski, Jaroslaw, Pawel Szczesny, Bartosz Pawlinski, Tomasz Mazurek, Piotr Zielenkiewicz, Zdzislaw Gajewski et Leszek Paczek. « Arteriovenous oscillations of the redox potential : Is the redox state influencing blood flow ? » Redox Report 22, no 5 (19 mai 2016) : 210–17. http://dx.doi.org/10.1080/13510002.2016.1177933.

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Maiya, Bhaskar G., Anthony Harriman, Jonathan L. Sessler, Gregory Hemmi, Toshiaki Murai et Thomas E. Mallouk. « Ground- and excited-state spectral and redox properties of cadmium(II) texaphyrin ». Journal of Physical Chemistry 93, no 24 (novembre 1989) : 8111–15. http://dx.doi.org/10.1021/j100361a027.

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Fahrenbach, Albert C., Carson J. Bruns, Dennis Cao et J. Fraser Stoddart. « Ground-State Thermodynamics of Bistable Redox-Active Donor–Acceptor Mechanically Interlocked Molecules ». Accounts of Chemical Research 45, no 9 (28 juin 2012) : 1581–92. http://dx.doi.org/10.1021/ar3000629.

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Fahrenbach, Albert C., Carson J. Bruns, Hao Li, Ali Trabolsi, Ali Coskun et J. Fraser Stoddart. « Ground-State Kinetics of Bistable Redox-Active Donor–Acceptor Mechanically Interlocked Molecules ». Accounts of Chemical Research 47, no 2 (16 décembre 2013) : 482–93. http://dx.doi.org/10.1021/ar400161z.

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35

Yaribeygi, Habib, Stephen L. Atkin et Amirhossein Sahebkar. « Potential roles of microRNAs in redox state : An update ». Journal of Cellular Biochemistry 120, no 2 (30 août 2018) : 1679–84. http://dx.doi.org/10.1002/jcb.27475.

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Fajı́n, José Luis Cagide, Javier López Cacheiro, Berta Fernández et Jan Makarewicz. « Fluorobenzene–argon ground-state intermolecular potential energy surface ». Journal of Chemical Physics 120, no 18 (8 mai 2004) : 8582–86. http://dx.doi.org/10.1063/1.1695553.

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Claudio, Gil C., et Eric R. Bittner. « Ground-state potential energy curves of phenylenevinylene oligomers ». Chemical Physics 276, no 2 (février 2002) : 81–91. http://dx.doi.org/10.1016/s0301-0104(01)00553-5.

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Boatz, Jerry A., Michael W. Schmidt et Mark S. Gordon. « Ground-state potential energy surface of phosphine oxide ». Journal of Physical Chemistry 91, no 7 (mars 1987) : 1743–49. http://dx.doi.org/10.1021/j100291a014.

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39

Stärck, J., et W. Meyer. « The ground state potential of the beryllium dimer ». Chemical Physics Letters 258, no 3-4 (août 1996) : 421–26. http://dx.doi.org/10.1016/0009-2614(96)00657-4.

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Ramiro Diaz, B., P. Wahnon et V. Sidis. « A calculated (KrO2)+ ground-state potential energy surface ». Chemical Physics Letters 212, no 3-4 (septembre 1993) : 218–22. http://dx.doi.org/10.1016/0009-2614(93)89317-b.

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Goodman, Lionel, Ali G. Ozkabak et Surya N. Thakur. « A benchmark vibrational potential surface : ground-state benzene ». Journal of Physical Chemistry 95, no 23 (novembre 1991) : 9044–58. http://dx.doi.org/10.1021/j100176a008.

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Koch, Henrik, Berta Fernández et Jan Makarewicz. « Ground state benzene–argon intermolecular potential energy surface ». Journal of Chemical Physics 111, no 1 (juillet 1999) : 198–204. http://dx.doi.org/10.1063/1.479266.

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Šurkus, A. A. « The ground-state potential energy function of PO+ ». Spectrochimica Acta Part A : Molecular Spectroscopy 48, no 10 (octobre 1992) : 1501–2. http://dx.doi.org/10.1016/0584-8539(92)80157-r.

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Akrawy, Dashty T. « α-decay half-lives of some nuclei from ground state to ground state using different nuclear potential ». EPJ Nuclear Sciences & ; Technologies 4 (2018) : 5. http://dx.doi.org/10.1051/epjn/2018001.

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Theoretical α-decay half-lives of some nuclei from ground state to ground state are calculated using different nuclear potential model including Coulomb proximity potential (CPPM), Royer proximity potential and Broglia and Winther 1991. The calculated values comparing with experimental data, it is observed that the CPPM model is in good agreement with the experimental data.
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Eberhart, Michael S., Brian T. Phelan, Jens Niklas, Emily A. Sprague-Klein, David M. Kaphan, David J. Gosztola, Lin X. Chen, David M. Tiede, Oleg G. Poluektov et Karen L. Mulfort. « Surface immobilized copper(i) diimine photosensitizers as molecular probes for elucidating the effects of confinement at interfaces for solar energy conversion ». Chemical Communications 56, no 81 (2020) : 12130–33. http://dx.doi.org/10.1039/d0cc05972b.

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46

Hui, Alice K., Richard L. Lord et Kenneth G. Caulton. « In search of redox non-innocence between a tetrazine pincer ligand and monovalent copper ». Dalton Trans. 43, no 21 (2014) : 7958–63. http://dx.doi.org/10.1039/c3dt52490f.

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Khan, Firoz Shah Tuglak, Amy L. Waldbusser, Maria C. Carrasco, Hadi Pourhadi et Shabnam Hematian. « Synthetic, spectroscopic, structural, and electrochemical investigations of ferricenium derivatives with weakly coordinating anions : ion pairing, substituent, and solvent effects ». Dalton Transactions 50, no 21 (2021) : 7433–55. http://dx.doi.org/10.1039/d1dt01192h.

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48

Kaur, Navjeet, Meenu Devi, Yamini Verma, Pooja Grewal, Pranshu Bhardwaj, Neha Ahlawat et Nirmala Kumari Jangid. « Photochemical Synthesis of Fused Five-membered O-heterocycles ». Current Green Chemistry 6, no 3 (18 décembre 2019) : 155–83. http://dx.doi.org/10.2174/2213346106666190904145200.

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Some transformations are not possible with ground-state reactions even in the presence of a catalyst, hence they are performed under photochemical conditions. Electron transfer occurs even with the photochemical excitement of one molecule where redox reaction is not possible at the ground state. The side products are obtained from ground-state reactions. For C-C bond formation during photochemical reactions, there is no requirement of any chemical activation of the substrates. Therefore, these reactions are presented here for the synthesis of fused five-membered O-heterocycles in the context of sustainable processes from 1964 to 2019.
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Chua, B. H., et B. J. Kleinhans. « Effect of redox potential on protein degradation in perfused rat heart ». American Journal of Physiology-Endocrinology and Metabolism 248, no 6 (1 juin 1985) : E726—E731. http://dx.doi.org/10.1152/ajpendo.1985.248.6.e726.

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The effect of redox potential on protein degradation was assessed in rat hearts supplied either glucose or pyruvate, and the correlation between redox state and proteolysis was examined after the addition of insulin and leucine. In hearts supplied glucose as the sole energy source, the inhibition of protein degradation by a range of concentrations of insulin was associated with increased ratios of perfusate lactate to pyruvate and intracellular lactate to pyruvate, malate to pyruvate, and NADH to NAD. However, the extent of inhibition did not correlate with the redox state. The inhibitory effect of leucine on protein degradation was not accompanied by any change in redox state of the hearts. In hearts provided with pyruvate, rates of protein degradation continued to be inhibited by insulin even though the perfusate lactate to pyruvate was decreased by 14-fold and the calculated cytosolic NADH-to-NAD ratios were only 3% of those seen in hearts supplied glucose. These results indicated that a correlation between redox state and protein degradation was not apparent in myocardium under the experimental conditions examined.
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Javadimanesh, E., H. Hassanabadi, A. A. Rajabi, H. Rahimov et S. Zarrinkamar. « Alpha Decay Half-Lives of Some Nuclei from Ground State to Ground State with Yukawa Proximity Potential ». Communications in Theoretical Physics 58, no 1 (juillet 2012) : 146–50. http://dx.doi.org/10.1088/0253-6102/58/1/19.

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