Energy transport in carbohydrates. Part IV. Energy transfer in cyclohepta-amylose complexes

Abstract

Irradiation of cyclohepta-amylose produces a free radical whose electron spin resonance spectrum consists mainly of a hyperfine structure doublet with a splitting of 3–4 gauss and line-width 24 gauss. It is suggested that the e.s.r. and chemical effects are best explained by production of a radical of the type –O–(C₆H₁₀O₄)–O·. Simultaneously, a carbonium ion is produced which would react with water: R⁺+ H₂O → ROH + H⁺

The effect of γ-radiation on the inclusion complexes of cyclohepta-amylose was examined. For the complexes with nitrophenols and iodobenzene the e.s.r. spectrum of the irradiated cyclohepta-amylose disappears and a spectrum different in form and intensity is observed. The complex with n-octanol does not show this behaviour. The observations are explained on the basis of energy transfer from the carbohydrate to the armotic moeity, which leads also to a marked reduction in the chemical degradation of cyclohepta-amylose. Energy scavenging in this way offers a promising method of protecting carbohydrates from radiation damage.