Publisher Summary This chapter discusses the role of free radicals and catalytic metal ions in human disease. The importance of transition metal ions in mediating oxidant damage naturally leads to the question as to what forms of such ions might be available to catalyze radical reactions in vivo . The chapter discusses the metabolism of transition metals, such as iron and copper. It also discusses the chelation therapy that is an approach to site-specific antioxidant protection. The detection and measurement of lipid peroxidation is the evidence most frequently cited to support the involvement of free radical reactions in toxicology and in human disease. A wide range of techniques is available to measure the rate of this process, but none is applicable to all circumstances. The two most popular are the measurement of diene conjugation and the thiobarbituric acid (TBA) test, but they are both subject to pitfalls, especially when applied to human samples. The chapter also discusses the essential principles of the peroxidation process. When discussing lipid peroxidation, it is essential to use clear terminology for the sequence of events involved; an imprecise use of terms such as initiation has caused considerable confusion in the literature. In a completely peroxide-free lipid system, first chain initiation of a peroxidation sequence in a membrane or polyunsaturated fatty acid refers to the attack of any species that has sufficient reactivity to abstract a hydrogen atom from a methylene group.

Role of free radicals and catalytic metal ions in human disease: an overview.

I. Introduction: Conceptual vs Fundamental andComputational Aspects of DFT1793II. Fundamental and Computational Aspects of DFT 1795A. The Basics of DFT: The Hohenberg−KohnTheorems1795B. DFT as a Tool for Calculating Atomic andMolecular Properties: The Kohn−ShamEquations1796C. Electronic Chemical Potential andElectronegativity: Bridging Computational andConceptual DFT1797III. DFT-Based Concepts and Principles 1798A. General Scheme: Nalewajski’s ChargeSensitivity Analysis1798B. Concepts and Their Calculation 18001. Electronegativity and the ElectronicChemical Potential18002. Global Hardness and Softness 18023. The Electronic Fukui Function, LocalSoftness, and Softness Kernel18074. Local Hardness and Hardness Kernel 18135. The Molecular Shape FunctionsSimilarity 18146. The Nuclear Fukui Function and ItsDerivatives18167. Spin-Polarized Generalizations 18198. Solvent Effects 18209. Time Evolution of Reactivity Indices 1821C. Principles 18221. Sanderson’s Electronegativity EqualizationPrinciple18222. Pearson’s Hard and Soft Acids andBases Principle18253. The Maximum Hardness Principle 1829IV. Applications 1833A. Atoms and Functional Groups 1833B. Molecular Properties 18381. Dipole Moment, Hardness, Softness, andRelated Properties18382. Conformation 18403. Aromaticity 1840C. Reactivity 18421. Introduction 18422. Comparison of Intramolecular ReactivitySequences18443. Comparison of Intermolecular ReactivitySequences18494. Excited States 1857D. Clusters and Catalysis 1858V. Conclusions 1860VI. Glossary of Most Important Symbols andAcronyms1860VII. Acknowledgments 1861VIII. Note Added in Proof 1862IX. References 1865

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Conceptual density functional theory.

6. Rehybridization of the Acceptor (RICT) 3908 7. Planarization of the Molecule (PICT) 3909 III. Fluorescence Spectroscopy 3909 A. Solvent Effects and the Model Compounds 3909 1. Solvent Effects on the Spectra 3909 2. Steric Effects and Model Compounds 3911 3. Bandwidths 3913 4. Isoemissive Points 3914 B. Dipole Moments 3915 C. Radiative Rates and Transition Moments 3916 1. Quantum Yields and Radiationless Deactivation Processes 3916

Structural Changes Accompanying Intramolecular Electron Transfer: Focus on Twisted Intramolecular Charge-Transfer States and Structures

There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

The use of dichlorofluorescin (DCFH) as a measure of reactive oxygen species was studied in aqueous media. Hydrogen peroxide oxidized DCFH to fluorescent dichlorofluorescein (DCF), and the oxidation was amplified by the addition of ferrous iron. Hydrogen peroxide-induced DCF formation in the presence of ferrous iron was completely inhibited by deferoxamine and partially inhibited by ethylenediaminetetraacetic acid, but was augmented by diethylenetriaminepentaacetic acid. Iron-peroxide-induced oxidation of DCFH was partially inhibited by catalase but not by horseradish peroxidase. Nonchelated iron-peroxide oxidation of DCFH was partially inhibited by several hydroxyl radical scavengers, but was independent of the scavenger concentration, and this suggests that free hydroxyl radical is not involved in the oxidation of DCFH in this system. Superoxide anion did not directly oxidize DCFH. Data suggest that H2O2-Fe(2+)-derived oxidant is mainly responsible for the nonenzymatic oxidation of DCFH. In addition, peroxidase alone and oxidants formed during the reduction of H2O2 by peroxidase oxidize DCFH. Since DCFH oxidation may be derived from several reactive intermediates, interpretation of specific reactive oxygen species involved in biological systems should be approached with caution. However, DCFH remains an attractive probe as an overall index of oxidative stress in toxicological phenomena.

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Evaluation of the probe 2',7'-dichlorofluorescin as an indicator of reactive oxygen species formation and oxidative stress.

The available data on gas phase basicities and proton affinities of molecules are compiled and evaluated. Tables giving the molecules ordered (1) according to proton affinity and (2) according to empirical formula, sorted alphabetically are provided. The heats of formation of the molecules and the corresponding protonated species are also listed.

Evaluated Gas Phase Basicities and Proton Affinities of Molecules; Heats of Formation of Protonated Molecules

1 General and theoretical aspects of the peroxide group (Robert D. Bach). 2 The structural chemistry of acyclic organic peroxides (Jens Hartung and Ingrid Svoboda). 3 Thermochemistry of peroxides (Suzanne W. Slayden and Joel F. Liebman). 4 17O NMR spectroscopy of organic compounds containing the O O group (Giovanni Cerioni and Francesca Mocci). 5 Synthesis of cyclic peroxides (Edward E. Korshin and Mario D. Bachi). 6 Synthetic uses of peroxides (Albrecht Berkessel and Nadine Vogl). 7 Analytical and safety aspects of organic peroxides and related functional groups (Jacob Zabicky). 8 Silicon and germanium peroxides (Wataru Ando). 9 Selective formation of allylic hydroperoxides via singlet oxygen ene reaction (Michael Orfanopoulos, Georgios C. Vougioukalakis and Manolis Stratakis). 10 Polar effects in decomposition of peroxidic compounds and related reactions (Sung Soo Kim). 11 Peroxides in biological systems (Jean Cadet and Paolo Di Mascio). 12 Sulfur and phosphorus peroxides (Vidyadhar Jadhav, Min Young Park and Yong Hae Kim). 13 Transition metal peroxides. Synthesis and role in oxidation reactions (Valeria Conte and Olga Bortolini). 14 Contemporary dioxirane chemistry: Epoxidations, heteroatom oxidations and CH insertions (Waldemar Adam and Cong-Gui Zhao). 15 Contemporary trends in dioxetane chemistry (Waldemar Adam and Alexei V. Trofimov). 16 Chemiluminescence of organic peroxides (Wilhelm J. Baader, C. V. Stevani and Erick L. Bastos). 17 Biomimetic Fe(II) chemistry and synthetic studies on antimalarial and antitumour endoperoxides (Paul M. O'Neill, James Chadwick and Sarah L. Rawe). Author index. Subject index.

The chemistry of peroxides

On trouve dans la litterature les valeurs: 2,0 et 1,4 V pour le potentiel de reduction standard du couple radical hydroxyl/hydroxyde. Les donnees thermochimiques donnent 1,98 V pour E°( • OHg/OH ap − ). L'hydratation du radical hydroxyl, par −5 kcal/mol, modifie cette valeur en 1,77 V pour E°'( • OH ap /OH aq − ), bien plus eleve que 1,4 V. On conclut que cette derniere valeur est incorrecte. On deduit les parametres thermodynamiques en accord avec la nouvelle valeur E°'. La reduction de H 2 O 2 par des complexes ferreux peut donner l'ion ferryl (FeO 2+ )-complexe)

The oxidizing nature of the hydroxyl radical. A comparison with the ferryl ion (FeO2

The estimation methods commonly used to correct phase change enthalpies to the standard state are compared where possible to experimental measurements. Heat capacity corrections for liquid-gas equilibria are found to correlate with molecular structure, and we suggest an improved method for estimating these corrections using group methods. A similar improvement for estimating heat capacity corrections for solid-gas equilibria using group methods is also proposed. Heat capacity corrections for liquid-solid equilibria are examined. These corrections were found to be comparable in magnitude to the experimental error associated with heat capacity measurements, so it was not possible to obtain any meaningful correlations.

Joel F. Liebman

Papers

Evaluated Gas Phase Basicities and Proton Affinities of Molecules; Heats of Formation of Protonated Molecules

The chemistry of peroxides

The oxidizing nature of the hydroxyl radical. A comparison with the ferryl ion (FeO2

Heat capacity corrections to a standard state: a comparison of new and some literature methods for organic liquids and solids

A survey of strained organic molecules.