Stable Radicals (eBook, PDF)

Fundamentals and Applied Aspects of Odd-Electron Compounds
Redaktion: Hicks, Robin

• Format: PDF

Produktbeschreibung

Stable radicals - molecules with odd electrons which are sufficiently long lived to be studied or isolated using conventional techniques - have enjoyed a long history and are of current interest for a broad array of fundamental and applied reasons, for example to study and drive novel chemical reactions, in the development of rechargeable batteries or the study of free radical reactions in the body. In Stable Radicals: Fundamentals and Applied Aspects of Odd-Electron Compounds a team of international experts provide a broad-based overview of stable radicals, from the fundamental aspects of specific classes of stable neutral radicals to their wide range of applications including synthesis, materials science and chemical biology. Topics covered include: * triphenylmethyl and related radicals * polychlorinated triphenylmethyl radicals: towards multifunctional molecular materials * phenalenyls, cyclopentadienyls, and other carbon-centered radicals * the nitrogen oxides: persistent radicals and van der Waals complex dimers * nitroxide radicals: properties, synthesis and applications * the only stable organic sigma radicals: di-tert-alkyliminoxyls. * delocalized radicals containing the hydrazyl [R2N-NR] unit * metal-coordinated phenoxyl radicals * stable radicals containing the thiazyl unit: synthesis, chemical, and materials properties * stable radicals of the heavy p-block elements * application of stable radicals as mediators in living-radical polymerization * nitroxide-catalyzed alcohol oxidations in organic synthesis * metal-nitroxide complexes: synthesis and magneto-structural correlations * rechargeable batteries using robust but redox-active organic radicals * spin labeling: a modern perspective * functional in vivo EPR spectroscopy and imaging using nitroxides and trityl radicals * biologically relevant chemistry of nitroxides Stable Free Radicals: Fundamentals and Applied Aspects of Odd-Electron Compounds is an essential guide to this fascinating area of chemistry for researchers and students working in organic and physical chemistry and materials science.

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Produktdetails

• Verlag: John Wiley & Sons
• Seitenzahl: 608
• Erscheinungstermin: 17. Juni 2010
• Englisch
• ISBN-13: 9780470666982
• Artikelnr.: 37298893

Autorenporträt

Professor Robin G. Hicks, Director, UVic Center for Advanced Materials and Related Technology (CAMTEC), Department of Chemistry, University of Victoria, BC Canada Robin Hicks has worked in the field of stable radicals for over 15 years and has published over 50 papers dealing with many different aspects of stable radical chemistry. Hicks' research has garnered several awards, including the Canadian Society for Chemistry Award for Pure or Applied Inorganic Chemistry in 2003. He  chaired the 10th International Conference on Molecule-based Magnets in Victoria, Canada, in 2006, and is the sole author of an authoritative, recent (2007) review on "stable organic radicals" in Organic and Biomolecular Chemistry.

Inhaltsangabe

Preface xv List of Contributors xvii 1. Triarylmethyl and Related Radicals 1 Thomas T. Tidwell 1.1 Introduction 1 1.1.1 Discovery of the triphenylmethyl radical 1 1.1.2 Bis(triphenylmethyl) peroxide 3 1.2 Free radical rearrangements 4 1.3 Other routes to triphenylmethyl radicals 5 1.4 The persistent radical effect 7 1.5 Properties of triphenylmethyl radicals 8 1.6 Steric effects and persistent radicals 9 1.7 Substituted triphenylmethyl radicals and dimers 9 1.8 Tris(heteroaryl)methyl and related triarylmethyl radicals 12 1.9 Delocalized persistent radicals: analogues of triarylmethyl radicals 14 1.10 Tetrathiatriarylmethyl (TAM) and related triarylmethyl radicals 16 1.11 Perchlorinated triarylmethyl radicals 20 1.12 Other triarylmethyl radicals 23 1.13 Diradicals and polyradicals related to triphenylmethyl 24 1.14 Outlook 28 Acknowledgements 28 References 28 2. Polychlorotriphenylmethyl Radicals: Towards Multifunctional Molecular Materials 33 Jaume Veciana and Imma Ratera 2.1 Introduction 33 2.2 Functional molecular materials based on PTM radicals 35 2.2.1 Materials with magnetic properties 37 2.2.2 Materials with electronic properties 53 2.2.3 Materials with optical properties 65 2.3 Multifunctional switchable molecular materials based on PTM radicals 69 2.3.1 Photo switchable molecular systems 69 2.3.2 Redox switchable molecular systems 70 2.4 Conclusions 75 References 76 3. Phenalenyls, Cyclopentadienyls, and Other Carbon-Centered Radicals 81 Yasushi Morita and Shinsuke Nishida 3.1 Introduction 81 3.2 Open shell graphene 82 3.3 Phenalenyl 84 3.4 2,5,8-Tri-tert-butylphenalenyl radical 86 3.5 Perchlorophenalenyl radical 92 3.6 Dithiophenalenyl radicals 94 3.7 Nitrogen-containing phenalenyl systems 97 3.7.1 Molecular design and topological isomers 97 3.7.2 2,5,8-Tri-tert-butyl-1,3-diazaphenalenyl 97 3.7.3 Hexaazaphenalenyl derivatives 102 3.7.4 ß-Azaphenalenyl derivatives 103 3.8 Oxophenalenoxyl systems 106 3.8.1 Molecular design and topological isomers 106 3.8.2 3-Oxophenalenoxyl (3OPO) system 108 3.8.3 4- and 6-Oxophenalenoxyl (4OPO, 6OPO) systems 110 3.8.4 Redox-based spin diversity 114 3.8.5 Molecular crystalline secondary battery 115 3.8.6 Spin-center transfer and solvato-/thermochromism 117 3.9 Phenalenyl-based zwitterionic radicals 119 3.10
-Extended phenalenyl systems 122 3.10.1 Triangulenes 122 3.10.2 Trioxytriangulene with redox-based spin diversity nature 125 3.10.3 Bis- and tris-phenalenyl system and singlet biradical characters 125 3.11 Curve-structured phenalenyl system 130 3.12 Non-alternant stable radicals 131 3.12.1 Cyclopentadienyl radicals 131 3.12.2 Cyclopentadienyl radicals within a larger
-electronic framework 135 3.13 Stable triplet carbenes 136 3.14 Conclusions 139 Acknowledgements 139 References 140 4. The Nitrogen Oxides: Persistent Radicals and van der Waals Complex Dimers 147 D. Scott Bohle 4.1 Introduction 147 4.2 Synthetic access 149 4.3 Physical properties 149 4.4 Structural chemistry of the monomers and dimers 150 4.4.1 Nitric oxide and dinitrogen dioxide 150 4.4.2 Nitrogen dioxide and dinitrogen tetroxide 152 4.5 Electronic structure of nitrogen oxides 153 4.6 Reactivity of nitric oxide and nitrogen dioxide and their van der Waals complexes 155 4.7 The kinetics of nitric oxide's termolecular reactions 156 4.8 Biochemical and organic reactions of nitric oxide 158 4.9 General reactivity patterns 160 4.9.1 Oxidation 160 4.9.2 Reduction 161 4.9.3 Coordination 162 4.9.4 Addition of nucleophiles 162 4.9.5 General organic reactions 165 4.9.6 Reactions with other nucleophiles 165 4.10 The colored species problem in nitric oxide chemistry 166 4.11 Conclusions 166 References 166 5. Nitroxide Radicals: Properties, Synthesis and Applications 173 Hakim Karoui, François Le Moigne, Olivier Ouari and Paul Tordo 5.1 Introduction 173 5.2 Nitroxide structure 174 5.2.1 Characteristics of the aminoxyl group 174 5.2.2 X-ray structures of nitroxides 175 5.2.3 Quantum mechanical (QM), molecular dynamics (MD) and molecular mechanics (MM) calculations 177 5.2.4 Influence of solvent polarity on the EPR parameters of nitroxides 180 5.3 Nitroxide multiradicals 181 5.3.1 Electron spin-spin exchange coupling 182 5.3.2 Miscellaneous aspects of di- and polynitroxides 184 5.4 Nitronyl nitroxides (NNOs) 185 5.4.1 Synthesis of nitronyl nitroxides 186 5.4.2 Nitronyl nitroxide as a nitric oxide trap 186 5.4.3 Nitronyl nitroxides as building blocks for magnetic materials 188 5.5 Synthesis of nitroxides 191 5.5.1 Oxidation of amines 191 5.5.2 Oxidation of hydroxylamines 191 5.5.3 Chiral nitroxides 191 5.5.4 Nitroxide design for nitroxide mediated polymerization (NMP) 193 5.6 Chemical properties of nitroxides 196 5.6.1 The Persistent Radical Effect 197 5.6.2 Redox reactions 197 5.6.3 Approaches to improve the resistance of nitroxides toward bioreduction 198 5.6.4 Hydrogen abstraction reactions 199 5.6.5 Cross-coupling reactions 200 5.6.6 Nitroxides in synthetic sequences 200 5.7 Nitroxides in supramolecular entities 206 5.7.1 Interaction of nitroxides with cyclodextrins 207 5.7.2 Interaction of nitroxides with calix[4]arenes 209 5.7.3 Interaction of nitroxides with curcubiturils 210 5.7.4 Interaction of nitroxides with micelles 211 5.7.5 Fullerene-linked nitroxides 212 5.8 Nitroxides for dynamic nuclear polarization (DNP) enhanced NMR 213 5.8.1 DNP for biological NMR and real-time metabolic imaging 213 5.8.2 Nitroxides as polarizing agents for DNP 214 5.9 Nitroxides as pH-sensitive spin probes 216 5.10 Nitroxides as prefluorescent probes 217 5.11 EPR-spin trapping technique 217 5.11.1 Immuno spin trapping 219 5.11.2 Conclusion 219 5.12 Conclusions 220 References 220 6. The Only Stable Organic Sigma Radicals: Di-tert-Alkyliminoxyls 231 Keith U. Ingold 6.1 Introduction 231 6.2 The discovery of stable iminoxyls 232 6.2.1 Synthesis of di-tert-butyl ketoxime 233 6.2.2 Synthesis of di-tert-butyliminoxyl 234 6.2.3 Stability of di-tert-butyliminoxyl 235 6.3 Hydrogen atom abstraction by di-tert-butyliminoxyl 236 6.3.1 The O
H bond dissociation enthalpy (BDE) in (Me 3 C) 2 C=NOH 236 6.3.2 Oxidation of hydrocarbons with di-tert-butyliminoxyl 237 6.3.3 Oxidation of phenols with di-tert-butyliminoxyl 238 6.3.4 Oxidation of amines with di-tert-butyliminoxyl 239 6.3.5 Oxidation of di-tert-butylketoxime with di-tert-butyliminoxyl 239 6.4 Other reactions and non-reactions of di-tert-butyliminoxyl 241 6.5 Di-tert-alkyliminoxyls more sterically crowded than di-tert-butyliminoxyl 241 6.6 Di-(1-Adamantyl)iminoxyl: a truly stable
radical 242 References 243 7. Verdazyls and Related Radicals Containing the Hydrazyl [R 2 N
NR] Group 245 Robin G. Hicks 7.1 Introduction 245 7.2 Verdazyl radicals 246 7.2.1 Synthesis of verdazyls 246 7.2.2 Stability, physical properties and electronic structure of verdazyls 250 7.2.3 Verdazyl radical reactivity 256 7.2.4 Inorganic verdazyl analogues 264 7.3 Tetraazapentenyl radicals 265 7.4 Tetrazolinyl radicals 266 7.5 1,2,4-Triazolinyl radicals 268 7.6 1,2,4,5-Tetrazinyl radicals 269 7.7 Benzo-1,2,4-triazinyl radicals 270 7.8 Summary 273 References 273 8. Metal Coordinated Phenoxyl Radicals 281 Fabrice Thomas 8.1 Introduction 281 8.2 General properties of phenoxyl radicals 282 8.2.1 Electronic structure and stabilization 282 8.2.2 Electrochemistry of phenoxyl radicals 283 8.2.3 Structure of non-coordinated phenoxyl radicals 284 8.2.4 UV-Vis spectroscopy 284 8.2.5 EPR spectroscopy 284 8.3 Occurrence of tyrosyl radicals in proteins 285 8.4 Complexes with coordinated phenoxyl radicals 287 8.4.1 General ligand structures 287 8.4.2 Vanadium complexes 290 8.4.3 Chromium complexes 291 8.4.4 Manganese complexes 292 8.4.5 Iron complexes 294 8.4.6 Cobalt complexes 297 8.4.7 Nickel complexes 299 8.4.8 Copper complexes 303 8.4.9 Zinc complexes 310 8.5 Conclusions 313 8.6 Abbreviations 313 References 313 9. The Synthesis and Characterization of Stable Radicals Containing the Thiazyl (SN) Fragment and Their Use as Building Blocks for Advanced Functional Materials 317 Robin G. Hicks 9.1 Introduction 317 9.2 Radicals based exclusively on sulfur and nitrogen 319 9.2.1 NS
and SNS
319 9.2.2 S3 N3
320 9.2.3 S3 N2
+ and related radical cations 320 9.2.4 Poly(thiazyl), (SN)X 322 9.3 "Organothiazyl" radicals 323 9.3.1 Thioaminyl radicals 323 9.3.2 1,2,3,5-Dithiadiazolyl radicals 329 9.3.3 1,3,2,4-Dithiadiazolyl radicals 336 9.3.4 1,3,2-Dithiazolyl radicals 339 9.3.5 1,2,3-Dithiazolyl radicals 342 9.3.6 Bis(1,2,3-dithiazole) and related radicals 345 9.3.7 1,2,4-Thiadiazinyl radicals 348 9.3.8 1,2,4,6-Thiatriazinyl and -selenatriazinyl radicals 349 9.3.9 Larger cyclic thiazyl radicals 355 9.4 Thiazyl radicals as "advanced materials" 355 9.4.1 Charge transport properties of thiazyl radicals 356 9.4.2 Thiazyl radical-based charge transfer salts 360 9.4.3 Magnetic properties of thiazyl radicals 364 9.5 Conclusions 373 References 373 10. Stable Radicals of the Heavy p-Block Elements 381 Jari Konu and Tristram Chivers 10.1 Introduction 381 10.2 Group 13 element radicals 382 10.2.1 Boron 382 10.2.2 Aluminum, gallium, and indium 384 10.3 Group 14 element radicals 388 10.3.1 Cyclic group 14 radicals 389 10.3.2 Acyclic group 14 radicals 391 10.4 Group 15 element radicals 395 10.4.1 Phosphorus 395 10.4.2 Arsenic, antimony, and bismuth 400 10.5 Group 16 element radicals 400 10.5.1 Sulfur 400 10.5.2 Selenium and tellurium 401 10.6 Group 17 element radicals 402 10.7 Summary and future prospects 403 References 404 11. Application of Stable Radicals as Mediators in Living-Radical Polymerization 407 Andrea R. Szkurhan, Julie Lukkarila and Michael K. Georges 11.1 Introduction 407 11.2 Living polymerizations 408 11.2.1 Living-radical polymerization background 408 11.3 Stable free radical polymerization 409 11.3.1 Background of the work performed at the Xerox Research Centre of Canada 409 11.3.2 General considerations and mechanism 410 11.3.3 Unimolecular initiators 411 11.3.4 Persistent radical effect 413 11.3.5 Requirements of stable radicals as mediating agents 413 11.3.6 Nitroxides as mediating agents 414 11.3.7 Nitroxides and their ability to moderate polymerizations 414 11.3.8 Rate enhancement of stable free radical polymerization through the use of additives 416 11.4 Non-nitroxide-based radicals as mediating agents 416 11.4.1 Triazolinyl radicals 416 11.4.2 Verdazyl radicals 417 11.4.3 Other radicals as mediators 418 11.5 Aqueous stable free radical polymerization processes 420 11.5.1 Living-radical miniemulsion polymerization 421 11.5.2 Emulsion polymerization 422 11.5.3 Other aqueous polymerization processes 423 11.6 The application of stable free radical polymerization to new materials 423 11.6.1 Statistical copolymers 423 11.6.2 Block copolymers 424 11.7 Conclusions 425 List of abbreviations 425 References 425 12. Nitroxide-Catalyzed Alcohol Oxidations in Organic Synthesis 433 Christian Brückner 12.1 Introduction 433 12.2 Mechanism of TEMPO-catalyzed alcohol oxidations 434 12.3 Nitroxides used as catalysts 435 12.3.1 Monomeric nitroxides 435 12.3.2 Ionic liquid nitroxides 436 12.3.3 Supported nitroxides 436 12.4 Chemoselectivity: oxidation of primary vs secondary alcohols 437 12.5 Chemoselectivity: oxidation of primary vs benzylic alcohols 438 12.6 Oxidation of secondary alcohols to ketones 439 12.7 Oxidations of alcohols to carboxylic acids 439 12.7.1 Oxidations leading to linear carboxylic acids 439 12.7.2 (Diol) oxidations leading to lactones 443 12.8 Stereoselective nitroxide-catalyzed oxidations 444 12.9 Secondary oxidants used in nitroxide-catalyzed reactions 446 12.9.1 Elemental halogens 446 12.9.2 Sodium hypochlorite (bleach) 446 12.9.3 Bis(acetoxy)iodobenzene (BAIB) 447 12.9.4 Oxygen (air) 448 12.9.5 Peroxides 449 12.9.6 Other organic secondary oxidants 450 12.9.7 Anodic, electrochemical oxidation 451 12.10 Use of nitroxide-catalyzed oxidations in tandem reactions 451 12.11 Predictable side reactions 453 12.11.1 Oxidations of sulfur 453 12.11.2 Oxidations of nitrogen 453 12.11.3 Oxidations of carbon 454 12.12 Comparison with other oxidation methods 454 12.13 Nitroxide-catalyzed oxidations and green chemistry 455 Acknowledgements 456 References 456 13. Metal-Nitroxide Complexes: Synthesis and Magnetostructural Correlations 461 Victor Ovcharenko 13.1 Introduction 461 13.2 Two types of nitroxide for direct coordination of the metal to the nitroxyl group 462 >N
O as a coordinating group 462 >N
O and other functional groups as donor fragments 464 13.3 Ferro- and ferrimagnets based on metal-nitroxide complexes 465 13.3.1 Molecular magnets based on 1-D systems 470 13.3.2 Molecular magnets based on 2-D systems 474 13.3.3 Molecular magnets based on 3-D systems 480 13.4 Heterospin systems based on polynuclear compounds of metals with nitroxides 483 13.4.1 Reactions whose products retain both the multinuclear fragment and nitroxide 484 13.4.2 Transformation of polynuclear fragments in reactions with nitroxides 487 13.4.3 Transformation of both the polynuclear fragment and the starting nitroxide 489 13.5 Breathing crystals 490 13.6 Other studies of metal-nitroxides 494 13.6.1 Analytical applications 494 13.6.2 NMR spectroscopy 494 13.6.3 Stabilization of nitroxides with ß-hydrogen atoms 496 13.6.4 Increased reactivity 496 13.6.5 Hidden exchange interactions 497 13.6.6 Contrast agents 499 13.7 Conclusions 500 References 500 14. Rechargeable Batteries Using Robust but Redox Active Organic Radicals 507 Takeo Suga and Hiroyuki Nishide 14.1 Introduction 507 14.2 Redox reaction of organic radicals 508 14.3 Mechanism and performance of an organic radical battery 509 14.4 Molecular design and synthesis of redox active radical polymers 512 14.4.1 Poly(methacrylate)s and poly(acrylate)s 512 14.4.2 Poly(vinyl ether)s and poly(allene)s 514 14.4.3 Poly(cyclic ether)s 514 14.4.4 Poly(norbornene)s 514 14.4.5 Poly(acetylene)s 514 14.4.6 Poly(styrene)s 515 14.4.7 Combination of radicals with biopolymers and ionic liquids 515 14.5 A totally organic-based radical battery 515 14.6 Conclusions 517 References 518 15. Spin Labeling: A Modern Perspective 521 Lawrence J. Berliner 15.1 Introduction 521 15.2 The early years 522 15.3 Advantages of nitroxides 523 15.4 Applications of spin labeling to biochemical and biological systems 524 15.4.1 Stoichiometry and specificity: proteins and enzymes 524 15.4.2 The reporter group approach: who makes the news? 525 15.5 Distance measurements 526 15.5.1 Metal-spin label distance measurements 526 15.5.2 Spin label-spin label distance measurements 526 15.5.3 Example of strong dipolar interactions 527 15.5.4 Multiple-quantum EPR and distance measurements 528 15.6 Site directed spin labeling (SDSL): how is it done? 529 15.6.1 The SDSL paradigm 530 15.6.2 SDSL parameters 530 15.7 Other spin labeling applications 531 15.7.1 pH sensitive spin labels 532 15.7.2 Spin labeled DNA - structure, dynamics and sequence analysis 532 15.8 Conclusions 534 References 534 16. Functional in vivo EPR Spectroscopy and Imaging Using Nitroxide and Trityl Radicals 537 Valery V. Khramtsov and Jay L. Zweier 16.1 Introduction 537 16.2 Nitroxyl radicals 538 16.3 Triarylmethyl (trityl) radicals 539 16.4 In vivo EPR oximetry using nitroxyl and trityl probes 539 16.4.1 Magnetic resonance approaches for in vivo oximetry 540 16.4.2 Nitroxide probes for EPR oximetry 540 16.4.3 TAM oximetric probes 545 16.5 EPR spectroscopy and imaging of pH using nitroxyl and trityl probes 547 16.5.1 pH-sensitive nitroxyl radicals 547 16.5.2 Dual function pH- and oxygen-sensitive trityl radicals 553 16.6 Redox- and thiol-sensitive nitroxide probes 556 16.6.1 Nitroxides as redox-sensitive EPR probes 556 16.6.2 Disulfide nitroxide biradicals as GSH-sensitive EPR probes 558 16.7 Conclusions 562 Acknowledgements 563 References 563 17. Biologically Relevant Chemistry of Nitroxides 567 Sara Goldstein and Amram Samuni 17.1 Introduction 567 17.2 Mechanisms of nitroxide reactions with biologically relevant small radicals 569 17.3 Nitroxides as SOD mimics 571 17.4 Nitroxides as catalytic antioxidants in biological systems 573 17.5 Conclusions 576 Acknowledgements 576 References 576 Index 579