Conversion constants for redox potentials measured versus different reference electrodes in acetonitrile solutions at 25°C
TL;DR: In this paper, a critical review of conversion constants amongst various reference electrodes reported in the literature reveals that in most cases the comparisons of redox potential values are far from accurate, and therefore, caution should be exercised when one is comparing the redox properties of complexes measured in CH 3 CN solutions versus different reference electrodes.
About: This article is published in Inorganica Chimica Acta.The article was published on 2000-01-30. It has received 1212 citations till now. The article focuses on the topics: Potentiometric titration & Reference electrode.
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TL;DR: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency as mentioned in this paper, and many DSC research groups have been established around the world.
Abstract: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...
8,707 citations
TL;DR: The conversion of these bench stable, benign catalysts to redox-active species upon irradiation with simple household lightbulbs represents a remarkably chemoselective trigger to induce unique and valuable catalytic processes.
Abstract: A fundamental aim in the field of catalysis is the development of new modes of small molecule activation. One approach toward the catalytic activation of organic molecules that has received much attention recently is visible light photoredox catalysis. In a general sense, this approach relies on the ability of metal complexes and organic dyes to engage in single-electron-transfer (SET) processes with organic substrates upon photoexcitation with visible light.
Many of the most commonly employed visible light photocatalysts are polypyridyl complexes of ruthenium and iridium, and are typified by the complex tris(2,2′-bipyridine) ruthenium(II), or Ru(bpy)32+ (Figure 1). These complexes absorb light in the visible region of the electromagnetic spectrum to give stable, long-lived photoexcited states.1,2 The lifetime of the excited species is sufficiently long (1100 ns for Ru(bpy)32+) that it may engage in bimolecular electron-transfer reactions in competition with deactivation pathways.3 Although these species are poor single-electron oxidants and reductants in the ground state, excitation of an electron affords excited states that are very potent single-electron-transfer reagents. Importantly, the conversion of these bench stable, benign catalysts to redox-active species upon irradiation with simple household lightbulbs represents a remarkably chemoselective trigger to induce unique and valuable catalytic processes.
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Figure 1
Ruthenium polypyridyl complexes: versatile visible light photocatalysts.
6,252 citations
TL;DR: An overview of the basic photophysics and electron transfer theory is presented in order to provide a comprehensive guide for employing this class of catalysts in photoredox manifolds.
Abstract: In this review, we highlight the use of organic photoredox catalysts in a myriad of synthetic transformations with a range of applications. This overview is arranged by catalyst class where the photophysics and electrochemical characteristics of each is discussed to underscore the differences and advantages to each type of single electron redox agent. We highlight both net reductive and oxidative as well as redox neutral transformations that can be accomplished using purely organic photoredox-active catalysts. An overview of the basic photophysics and electron transfer theory is presented in order to provide a comprehensive guide for employing this class of catalysts in photoredox manifolds.
3,550 citations
TL;DR: In this article, a short introduction to cyclic voltammetry is provided to help the reader with data acquisition and interpretation, and common pitfalls are provided, and the reader is encouraged to apply what is learned in short, simple training modules provided in the Supporting Information.
Abstract: Despite the growing popularity of cyclic voltammetry, many students do not receive formalized training in this technique as part of their coursework. Confronted with self-instruction, students can be left wondering where to start. Here, a short introduction to cyclic voltammetry is provided to help the reader with data acquisition and interpretation. Tips and common pitfalls are provided, and the reader is encouraged to apply what is learned in short, simple training modules provided in the Supporting Information. Armed with the basics, the motivated aspiring electrochemist will find existing resources more accessible and will progress much faster in the understanding of cyclic voltammetry.
1,779 citations
TL;DR: Narrow bandgap conjugated polymers in combination with fullerene acceptors, as well as the values used for the absolute potentials of standard electrodes, can complicate the comparison of materials properties and determination of structure/property relationships.
Abstract: Narrow bandgap conjugated polymers in combination with fullerene acceptors are under intense investigation in the field of organic photovoltaics (OPVs). The open circuit voltage, and thereby the power conversion efficiency, of the devices is related to the offset of the frontier orbital energy levels of the donor and acceptor components, which are widely determined by cyclic voltammetry. Inconsistencies have appeared in the use of the ferrocenium/ferrocene (Fc + /Fc) redox couple, as well as the values used for the absolute potentials of standard electrodes, which can complicate the comparison of materials properties and determination of structure/property relationships.
1,681 citations
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4,768 citations
TL;DR: 1. Advantages and disadvantages of Chemical Redox Agents, 2. Reversible vs Irreversible ET Reagents, 3. Categorization of Reagent Strength.
Abstract: 1. Advantages of Chemical Redox Agents 878 2. Disadvantages of Chemical Redox Agents 879 C. Potentials in Nonaqueous Solvents 879 D. Reversible vs Irreversible ET Reagents 879 E. Categorization of Reagent Strength 881 II. Oxidants 881 A. Inorganic 881 1. Metal and Metal Complex Oxidants 881 2. Main Group Oxidants 887 B. Organic 891 1. Radical Cations 891 2. Carbocations 893 3. Cyanocarbons and Related Electron-Rich Compounds 894
3,432 citations
TL;DR: In this article, the authors indique les procedes pour la mesure et le report des potentiels d'electrode dans des solvants non aqueux, vis-a-vis de ces systemes redox de reference.
Abstract: On montre que les couples redox ferrocene/ion ferricenium, [ferrocene: bis(η-cyclopentadienyl) fer(II)] et bis(biphenyl) chrome(I)/bis(biphenyl)-chrome(o) peuvent etre utilises comme systemes redox de reference. On indique les procedes pour la mesure et le report des potentiels d'electrode dans des solvants non aqueux, vis-a-vis de ces systemes redox de reference. Donnees numeriques obtenues dans 22 solvants organiques
1,168 citations
TL;DR: In this paper, the authors proposed a universal reference electrode for nonaqueous solvents, such as the normal hydrogen electrode (NHE) or saturated calomel electrode (SCE).
Abstract: Electrochemistry is an increasingly popular technique for the characterization of new compounds. The basic thermodynamic quantity that is assigned to an electrode process is the standard or formal reduction potential (E^o or E^f). In aqueous solution the measurement of reduction potentials is facilitated by the use of reliable and universally accepted reference electrodes such as the normal hydrogen electrode (NHE) or the saturated calomel electrode (SCE). In many instances electrochemical measurements in water are impossible due to insolubility or instability of the compound. Unfortunately, no universal reference electrode exists for nonaqueous solvents.
914 citations
TL;DR: In this article, a ligand electrochemical parameter, El (L), is described to generate a series which may be used to predict M(n)/M(n-1) redox potentials by assuming that all ligand contributions are additive.
Abstract: : A ligand electrochemical parameter, El (L), is described to generate a series which may be used to predict M(n)/M(n-1( redox potentials by assuming that all ligand contributions are additive. In this fashion it performs a similar purpose to the Dq parameter in electronic spectroscopy. The parameter is defined as 1/6 that of the Ru(III)/Ru(II) potential for species RuL6 in acetontrile. The El(L) values for over 200 ligands are presented and the model is tested over a wide range of coordination complexes and organometallic species. The redox potential of a M(n)/M(n-1) couple is defined to be equal to:- E(calc) = f Sigma EL (L) + c. The values of f and C, which are tabulated, depend upon the metal and redox couple, and upon spin state and stereochemistry, but, in organic solvents, are generally insensitive to the net charge of the species. Consideration is given to synergism, the potentials of isomeric species, and the situations where the ligand additivity model is expected to fail. In this initial study, the redox couples are restricted almost exclusively to those involving the loss or addition of an electron to the tzg (in Oh) sub-level.
832 citations