Na°(Epoxy)i_3 complexes and dissociative electron capture of the epoxy system: Matrix isolation esr study

Abstract

It is postulated that a high electron beam sensitivity of epoxylated poly(meth)acrylate results from the dissociative electron capture by the epoxy moiety. [inline formula omitted] Na atoms and epoxy molecules (ethylene oxide, trimethylene oxide, and tetrahydrofuran) were cocondensed in argon matrices, and the Na-to-epoxy electron transfer was induced by mild radiation (λ > 580 nm). ESR examination of the matrices demonstrated that ethylene oxide and trimethylene oxide, but not tetrahydrofuran, readily captured low-energy electrons, and the resulting anions had the structure consistent with the postulated ring opening. The conformations of the radical anions were determined from the a and ß proton hyperfine coupling tensors. The ESR study also revealed the formation of (epoxy)1-3Na° complexes upon cocondensation of Na atoms and the epoxy molecules examined in argon matrices. Spectral analyses revealed that these complexes were formed through dative interaction of the oxygen lone pair electrons with the vacant Na orbitals, and the unpaired electron was in an sp hybridized orbital of the Na atom pointing away from the ligand(s). © 1990, American Chemical Society. All rights reserved.