Electron Spin-Echo Envelope Modulation and Pulse Electron Nuclear Double Resonance Studies of Cu~(2+)...beta-Carotene Interactions in Cu-MCM-41 Molecular Sieves

摘要

Perdeuterated all-trans beta-carotene imbedded in activated Cu-MCM-41 was examined by electron paramagnetic resonance (EPR) and electron spin-echo envelope modulation (ESEEM) spectroscopies.The EPR study showed that complexation and electron transfer between Cu~(2+) and deuterated beta-carotene occurs.The interaction was confirmed by detecting the spin-echo modulation of deuterium in the ESEEM spectra of Cu~(2+).Ratio analysis of ESEEM was used to determine the number of deuterons which interact with Cu~(2+) and the distance between deuteron(s) and Cu~(2+).The bonding site of beta- carotene determined by ESEEM and pulse electron nuclear double resonance is the C15=C15' double bond.