EPR-Untersuchung der g-Faktoren und Chlor-Hyperfeinstrukturen von gelösten aliphatischen Radikalen

Abstract

For a series of alkyl radicals we have measured the electron g factors and hfs splitting constants by EPR methods. The isotropic chlorine hfs constants are discussed in terms of the Karplus-Fraenkel formula αCl=Q_CCl ^Cl _Qc. The results indicate that Q_Cl = Δ (Cl) Q_C ^π with Δ (Cl) =0.16. From this and Fischer’s Δ (Xi) parameters for the other substituents, effective σ-π-parameters could be determined to be There exists a proportional relationship between the g factor shift ΔgCl due to chlorine substituents and _Cl ^Σ Q_Cl ^π from which ΔE_n→π ^Cl =15.6·10³ cm^-1 was determined. CI