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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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