Carbon-Centered Free Radicals and Radical Cations: Structure, Reactivity, and Dynamics

by Editor: Malcolm D. Forbes

• ISBN13: 9780470584101
• ISBN10: 0470584106
• Format: eBook
• Copyright: 2010-01-01
• Publisher: Wiley

Summary

The chemistry and biochemistry of reactive intermediates is central to modern mechanistic and quantitative understanding of organic chemistry and biochemistry. The only comprehensive review to cover carbon-centered radical intermediates and their role(s) in chemistry and biochemistry, Carbon-Centered Radicals provides detailed explanations of the role of these intermediates in organic reactions and detailed discussions of their versatility with respect to functional groups to help graduate students and professional researchers better understand and expand their synthetic utility.

Table of Contents

About the Volume Editor

Preface to Series

Introduction

Contributors

A Brief History of Carbon Radicals

Intermolecular Radical Additions to Alkynes: Cascade-Type Radical Cyclizations

Introduction

Cascade Reactions Involving Radicals of Second Row Elements

Cascade Reactions Initiated by Addition of Higher Main Group (VI)-Centered Radicals to Alkynes

Cascade Reactions Initiated by Addition of Higher Main Group (VI)-Centered Radicals to Alkynes

Cascade Reactions Initiated by Addition of Higher Main Group (V)-Centered Radicals to Alkynes

Radical Cation Fragmentation Reactions in Organic Synthesis

Introduction

Electron Transfer-Initiated Cyclization Reactions

Oxidative Acyliminium Ion Formation

Carbon-Carbon Bond Formation

Summary and Outlook

Selectivity in Radical Cation Cycloadditions

Introduction

Mechanism and the Origin of the Rate Acceleration

Selectivity in Radical Cation Cycloadditions

Chemoselectivity

Regioselectivity

Periselectivity

Endo/Exo Selectivity

Conclusions

The Stability of Carbon-Centered Radicals

Introduction

Theoretical Methods

RSE Values for Carbon-Centered Radicals

Use of RSE Values in Practical Applications

Conclusions

Interplay of Stereoelectronic Vibrational and Environmental Effects in Tuning Physicochemical Properties of Carbon-Centered Radicals

Introduction

EPR Spectroscopy

Calculation of EPR Parameters

Vibrational Properties Beyond the Harmonic Approximation

Electronic Properties: Vertical Excitation Energies, Structure, and Frequencies in Excited Electronic States

Vibronic Spectra

Concluding Remarks

Unusual Structures of Radical Ions in Carbon Skeletons: Nonstandard Chemical Bonding by Restricting Geometries

Introduction

The Tools

Pagodane and Its Derivatives

Different Stages of Cycloaddition/Cycloreversion Reactions Within Confined Environments

Extending the ''Cage Concept''

Summary

Magnetic Field Effects on Radical Pairs in Homogeneous Solution

Introduction

The Spin-Correlated Radical Pair

Application of a Magnetic Field

Spin-State Mixing

The Magnetic Field Dependence of Radical Pair Reactions

Theoretical Approaches

Experimental Approaches

The Life Cycle of Radical Pairs in Homogeneous Solution

Summary

Chemical Transformations Within the Paramagnetic World Investigated by Photo-CIDNP

Introduction

CIDNP Theory

Experimental Methods

Radical-Radical Transformations During Diffusive Excursions

Radical-Radical Transformations at Reencounters

Interconversions of Biradicals

Conclusions

Spin Relaxation in Ru-Chromophore-Linked Azine/Diquat Radical Pairs

Introduction

EPR for the Isolated Ions

Calculation Methods for EPR of the Isolated Ions

Implications for Spin-Relaxation in Linked Radical Pairs

Reaction Dynamics of Carbon-Centered Radicals in Extreme Environments Studied by the Crossed Molecular Beam Technique

Introduction

The Crossed Molecular Beam Method

Experimental Setup

Crossed Beam Studies

Conclusions

Laser Flash Photolysis of Photoinitiators: ESR, Optical, and IR Spectroscopy Detection of Transients

Introduction

Photodissociation of Initiators

TR ESR Detection of Transients

Optical Detection of Transients

IR Detection of Free Radicals and Monitoring Their Reactions

Concluding Remarks

Dynamics of Radical Pair Processes in Bulk Polymers

Introduction

Singlet-State Radical Pairs from Irradiation of Aryl Esters and Alkyl Aryl Ethers

General Mechanistic Considerations From Solution and Gas-Phase Studies

Photo-Reactions of Aryl Esters in Polymer Matrices. Kinetic Information from Constant Intensity Irradiations

Rate Information from Constant Intensity Irradiation of Alkyl Aryl Ethers

Comparison of Calculated Rates to Other Methods for Polyethylene Films

Triplet-State Radical Pairs

Concluding Remarks

Acrylic Polymer Radicals: Structural Characterization and Dynamics

Introduction

The Photodegradation Mechanism

Polymer Structures

The Time-Resolved EPR Experiment

Tacticity and Temperature Dependence of Acrylate Radicals

Structural Dependence

Oxo-Acyl Radicals

Spin Polarization Mechanisms

Solvent Effects

Dynamic Effects

Conclusions

Index

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