Radical-ion generation and trapping in neon matrices at 4 K. Electron spin resonance investigations of F2COÂ± and C+2
Knight, L. B.; Ott, J. Radical-ion generation and trapping in neon matrices at 4 K. Electron spin resonance investigations of F2COÂ± and C+2. Faraday Discuss. Chem. Soc. 1988, 86, 71-71.
Radical-ion e.s.r. studies in neon matrices are summarized briefly and new results are presented for 12,13C+2(X 4Î£) and F2COâ€“, with a tentative assignment for F2CO+. These examples illustrate the flexibility of the neon matrix-deposition method in trapping volatile as well as refractory ion radicals in an inert environment at 4 K. A pulsed-laser vaporization procedure combined with photoionization was used to generate C+2 from 12C and 13C graphite targets. The electronic ground state determined for C+2 in this e.s.r. study agrees with recent assignments from electronic measurements. The F2COâ€“ anion appears to be a carbon-centred radical based on the properties of its 13C A tensor, which has a large Aiso value of 715 MHz. The anion, which is isoelectronic to CF3, deviates from C2v symmetry, and the magnetic inequivalency of its 19F nuclei complicates the e.s.r. spectrum. The observed A tensors for 19F and 13C are compared with calculated values conducted at various levels of theory. The F2COâ€“ radical was generated by two independent methods, electron addition to F2CO(g) by photoionization and the codeposition of F2CO(g) with Na(g) into neon and argon matrices.
Faraday Discussions of the Chemical Society