Magnetic Field Effects on the Dynamics of Biradicals Generated from Benzophenone and Diphenylamine Bifunctional Chain Molecules

Abstract

Abstract The magnetic field effects (MFE) on the lifetimes of triplet biradicals generated from the intramolecular photoreaction of bifunctional chain molecules, α-(4-benzoylphenoxy)-ω-[4-(phenylamino)phenoxy]alkanes (BP–O–n–O–DPA, n=2–16) were studied by laser flash photolysis. MFE on the biradical lifetimes are strongly affected by magnetic field, chain length, and solvent. The effects are interpreted in terms of the hf-relaxation mechanism. Lifetime change due to T−–S level crossing was observed in the biradicals with n=2 and 4. The singlet and triplet degeneracy of biradicals occurs when n≥6.