Advances in Physical Organic Chemistry

1st Edition, Volume 45 - September 12, 2011
Editor: John P. Richard
Language: English
Hardback ISBN:
9 7 8 - 0 - 1 2 - 3 8 6 0 4 7 - 7
eBook ISBN:
9 7 8 - 0 - 1 2 - 3 8 6 0 4 8 - 4

Advances in Physical Organic Chemistry provides the chemical community with authoritative and critical assessments of the many aspects of physical organic chemistry. The field… Read more

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Advances in Physical Organic Chemistry provides the chemical community with authoritative and critical assessments of the many aspects of physical organic chemistry. The field is a rapidly developing one, with results and methodologies finding application from biology to solid state physics.

Advances in Physical Organic Chemistry
Editor’s Preface
Contributors to Volume 45
Kinetically and thermodynamically controlled syntheses of covalent molecular capsules

1 Introduction
2 Methods
3 Summary

The generation and reactions of quinone methides

1 Introduction
2 Generation of quinone methides by photochemical reactions
3 Generation of quinone methides by heterolytic bond cleavage
4 Generation of quinone methides by unmasking a quinone oxygen
5 Generation of quinone methides by nucleophilic aromatic substitution of water at carbocations
6 Generation of quinone methides by oxidation of phenols
7 Generation of quinone methides by reductive elimination reactions of quinones
8 Other pathways for generation of quinone methides
9 Structure–reactivity studies on nucleophile addition to quinone methides
10 O-Alkylation and O-protonation of the quinone oxygen: reactivity effects
11 O-Protonation of the quinone oxygen: stability effects
12 O-Alkylation and O-protonation of the quinone methide oxygen: effect on intrinsic reaction barriers
13 O-Alkylation of the quinone methide oxygen: effect on Hammett reaction constants
14 ortho-Quinone and ortho-thioquinone methides
15 The di--CF₃-substituted quinone methide

Structure–property relationships for metal-free organic magnetic materials

1 Scope and limitations of this chapter
2 Some important basics of organic radicals as spin bearing building blocks
3 Skill sets for basic magnetostructural analysis
4 Organic building blocks for magnetism – design of high-spin organic molecules
5 Magnetism as a consequence of exchange interactions between spin units
6 Assembly of organic spin units into polyspin oligomers and polymers
7 Magnetic materials composed of organic molecular spin units – a brief overview
8 Organic radical magnetic materials lacking directional crystal assembly functionality
9 Assembly of radicals by phenolic hydrogen bonding
10 Assembly of hydrogen-bonded heterospin dyads
11 Assembly of radicals by benzimidazole hydrogen bonding
12 Conclusion

No barrier theory and the origins of the intrinsic barrier

1 History of the idea
2 N-Dimensional reaction coordinate diagrams
3 Energies of the corner species
4 Assumptions behind No Barrier Theory
5 Current range of reactions that can be treated by NBT
6 Problems remaining

Author Index
Cumulative Index of Authors
Cumulative Index of Titles
Subject Index

John P. Richard

John Richard received his Ph.D. from Ohio State University, under the direction of Perry Frey. His thesis reported the synthesis of chiral oxygen-18 labelled phosphorothioate analogs of adenine nucleotides, and their use to determine the stereochemical course for enzyme-catalyzed phosphoryl transfer reactions. He worked as a postdoctoral fellow at Brandeis University with Bill Jencks, and developed an azide ion clock to measure the lifetimes of carbocation intermediates of solvolysis reactions. This clock was used to show that the mechanism for nucleophilic substitution reactions at ring-substituted 1 phenylethyl derivatives is controlled by the lifetimes of the carbocation intermediates of the solvolysis reaction. He began his independent career at the Department of Chemistry at the University of Kentucky in 1985 and moved to SUNY Buffalo in 1993. Richard is interested in understanding the mechanism for the reactions of small molecules in water, and for their catalysis by enzymes. His early independent studies focused on developing methods to determine rate and equilibrium constants for reactions of simple carbanions and carbocations intermediates of organic reactions in water. This led to a broad characterization of substituent effects on the stability of these intermediates, and a rationale for the observation that many polar electron-withdrawing substituents cause a decrease in both the stability and reactivity of resonance stabilized carbocations. Richard transitioned to studies on the mechanism for small molecule catalysis in models for enzyme-catalyzed reactions. These included proton transfer, hydride transfer, aldol condensation reactions, and phosphate diester hydrolysis. Most recently he has focused on determining the mechanism for the stabilization of reactive carbocation and carbanion enzymatic reaction intermediates through interactions with active-site protein side chains. An important outcome of this work is the determination that the most proficient enzyme catalysts of metabolic reactions utilize substrate binding interactions as glue in the construction of protein-substrate cages that provide a tremendous stabilization of carbanion and carbocation reaction intermediates. These results provide a simple rational for the existence of enzyme catalysts that follow Koshland's induced-flt mechanism.

Affiliations and expertise

Department of Chemistry, University of Buffalo, NY, USA

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Advances in Physical Organic Chemistry

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John P. Richard