Basic principles and applications

of spin chemistry

(a brief review)

Maria Vyushkova

Notre Dame Radiation Laboratory, April 2011

What is spin chemistry? Definition, history & introductory notes

Radical pairs, radical pair reaction mechanism, spin correlation in a pair

Methods of radical pair generation/detection of products

CIDEP and CIDNP

Outline

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Methods of radical pair generation

To create radicals, it usually requires the input of external energy:

UV/visible light (photochemical generation)

photo-CIDNP – the most ubiquitous spin chemistry techniqueSNP, RYDMR, MARY, time resolved EPR

Ionizing irradiation (radiation chemistry)

radiofluorescence techniques: OD EPR, MARY, quantum beatsspectroscopy; time resolved EPR

Photochemical generation:

Absorbing molecules of photosensitizer in a “transparent” solvent => selective

and uniform production of the excited solute molecules

Decomposition/electron transfer of the excited state (S1 or T1) of the precursor

Both singlet and triplet-born radical pairs (ISC mechanism)

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Generation of radical pairs by ionizing radiation:

an “overkill” method in terms of photon/particle energy

each photon/particle produces many ionizations/excited states along its track

the “bulk” solvent molecules are ionized/excited

References (what to read on spin chemistry)

1. K.M. Salikhov, Yu.N. Molin, R.Z. Sagdeev, A.L. Buchachenko. Spin

Polarization and Magnetic Effects in Radical Reactions. Elsevier,

Amsterdam-Oxford-New York-Tokyo, 1984

2. U.E. Steiner and T. Ulrich. Magnetic Field Effects in Chemical Kinetics

and Related Phenomena // Chem. Rev. 1989, 89, p, 51-147

3. H. Hayashi. Introduction to Dynamic Spin Chemistry. Magnetic Field

Effects on Chemical and Biochemical Reactions. World Scientific, 2004

4. J.R. Woodward. Radical Pairs in Solution. //Progress in Reaction Kinetics

and Mechanism, 2002, 27, p. 65-207

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