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Spin Photochemistry: Electron Spin Multiplicity as a Tool for Reactivity and Selectivity Control.

Axel G Griesbeck¹, Seyma Bozkus²

¹Department of Chemistry, Faculty of Natural Sciences and Mathematics, Greinstr. 4, University of Cologne, 50939 Köln-Cologne, Germany;,

|November 3, 2021

Summary

Spin chemistry in small organic molecules is sensitive to spin-orbit-coupling and hyperfine coupling. Reaction properties like selectivity and quantum yields can track spin dynamics and selectivity in these systems.

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Area of Science:

Chemistry
Physical Chemistry
Quantum Chemistry

Background:

Spin chemistry explores the role of electron spin in chemical reactions.
Small organic molecules lacking heavy atoms present unique challenges and opportunities in spin dynamics.
Spin-orbit-coupling (SOC) and hyperfine coupling (HFC) are key interactions influencing spin states.

Purpose of the Study:

To investigate the sensitivity of spin chemistry in small organic molecules to SOC and HFC.
To establish reaction properties as analytical tools for studying intersystem crossing (ISC) dynamics.
To enable the titration of spin selectivities in these systems.

Main Methods:

Utilizing chemo-, regio-, and diastereoselectivity as indicators of spin dynamics.
Employing quantum yields to monitor intersystem crossing (ISC) processes.
Analyzing magnetic isotope interactions modulated by hyperfine coupling (HFC).

Main Results:

Demonstrated the significant influence of SOC on biradical conformation.
Showcased HFC's role in modulating magnetic isotope interactions.
Validated reaction properties as effective tools for tracking ISC dynamics.

Conclusions:

Spin chemistry in small organic molecules is highly tunable via SOC and HFC.
Reaction selectivities and quantum yields provide quantitative measures of spin dynamics.
This approach allows for precise control and analysis of spin-selective reactions.