Isotopic perturbation of resonance in a homologous series of metal complexes with allylic cation character

Perrin, Charles L.; Kim, Yeong‐Joon

doi:10.1002/1099-1395(200011)13:11<752::aid-poc320>3.3.co;2-w

Cited by 2 publications

(2 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…I proposed an alternative to Breslow's mechanism for buffer‐catalyzed hydrolysis of RNA models . We demonstrated that isotopic perturbation of resonance is real, in a series of metal complexes . We measured the intramolecular KIE for hydride transfer from an NADH model to a quinolinium ion and found that it is inconsistent with the intermolecular IEs that had been claimed as evidence for a two‐step mechanism.…”

Section: Researchmentioning

confidence: 91%

Half a century of research, teaching, service

Perrin

2014

J of Physical Organic Chem

Self Cite

View full text Add to dashboard Cite

This is a summary of the research of Charles L. Perrin and his coworkers in the areas of aromatic mercuration, vibronic borrowing, ipso factors in electrophilic aromatic substitution, malonic anhydrides, mechanisms of proton exchange in amides, stereoelectronic control, the socalled reverse anomeric effect, an NMR titration method for highly accurate measurement of relative acidities, secondary deuterium isotope effects on acidity, symmetry of hydrogen bonds in solution, and nucleophilic addition to a para-benzyne diradical, along with Perrin's contributions to teaching and to service. Keywords:hydrogen bonds para-benzyne NMR titration isotope effects stereoelectronic control reverse anomeric effect vibronic borrowing electrophilic aromatic substitution malonic anhydrides proton exchange in amides Special thanks go to my dear wife Marilyn for her presence and support during these fifty years and for preparing a delicious dinner for the speakers and out-of-town guests the night before the symposium.After 50 years at UCSD I am still not retired but continue to enjoy teaching and research.

show abstract

Section: Researchmentioning

confidence: 91%

Half a century of research, teaching, service

Perrin

2014

J of Physical Organic Chem

Self Cite

View full text Add to dashboard Cite

show abstract

“…Some topics were omitted from this discussion because their pursuit did not develop logically from other projects. Among these are (1) the pH dependence of the rates of NH exchange of aqueous biotin, (2) variable-temperature NMR without a variable-temperature probe, (3) an unusually strong dependence of conformation on solvent, arising from steric hindrance to solvation of a neutral amine that is hydrogen-bonded to water, (4) isotopic perturbation of resonance, (5) adaptation of a More O’Ferrall–Jencks diagram to support a mechanism involving electron transfer concerted with heavy-atom motion, (6) measurement of a solvent KIE, leading to the complete mechanism of aldol condensation …”

Section: Topics Omittedmentioning

confidence: 99%

The Logic behind a Physical–Organic Chemist’s Research Topics

Perrin

2016

J. Org. Chem.

Self Cite

View full text Add to dashboard Cite

Abstract. Although my research has no common theme or defining area, a coherence connects the diverse topics, insofar as one project leads logically to another. Thus studies on mechanisms of hydrogen exchange in amides and amidines led to the influence of hydrogenbonding and to NMR methods for chemical kinetics, including 2D-EXSY spectroscopy.Another connection was the OH --catalyzed NH exchange in amines that had supported the hypothesis of stereoelectronic control. We therefore analyzed that hypothesis critically, tested it, found counterexamples, and proposed an alternative hypothesis. We next addressed one-bond NMR coupling constants in ethers and the reverse anomeric effect. The latter studies required a highly accurate NMR titration method that we developed to measure the additional steric bulk resulting from protonation of a substituent. This method is also applicable to measuring secondary isotope effects on acidity, and we could demonstrate that they arise from n-* delocalization, not from an inductive effect. Other studies included kinetic isotope effects for both dissociation and H exchange of aqueous NH 4 + , for C-N rotation in amides, and for a hydride transfer. The role of hydrogen-bonding led us to the rotation of NH 4 + within its solvent cage and then to the symmetry of hydrogen bonds. This review article is based on an address presented at the 249th National Meeting of the American Chemical Society in Denver CO, on the occasion of the James Flack Norris Award in Physical-Organic Chemistry. 1 It demonstrates the ways whereby one physicalorganic chemist, and physical-organic chemists in general, have investigated how molecular structure affects chemical reactivity. It also seeks to confirm my claim that "In my opinion, 2 physical organic chemistry represents the intellectual basis of organic chemistry. It asks (and answers!) fundamental questions about how chemical substances behave, and it rationalizes that behavior." 2 The reason that I won the James Flack Norris Award was for my "insight, rigorous analysis, and understanding of mechanisms and reactive intermediates", rather than any distinctive area of research with which I am associated. Instead of choosing one area to review here, I have tried to describe the path of my research for the past 40 years, as an expansion of an earlier article on this topic. 3 Each area seems to have engendered additional questions, leading to additional areas. Often those questions are marked by an intense skepticism, and the answers to those questions are supported by a logical analysis that I am proud of. I hope that this article will be as interesting, informative, and enjoyable to the reader as the research described here has been for me. A Beginner's ResearchMy Ph.D. thesis research was on mercuration of benzene, an electrophilic aromatic substitution that is accelerated by strong acid, and where we measured the H/D kinetic isotope effect. 4 To understand the origin of the acceleration it was necessary to consider acidity functions, including a new one, H...

show abstract

Isotopic perturbation of resonance in a homologous series of metal complexes with allylic cation character

Cited by 2 publications

References 11 publications

Half a century of research, teaching, service

Half a century of research, teaching, service

The Logic behind a Physical–Organic Chemist’s Research Topics

Contact Info

Product

Resources

About