Preparation and photoelectron spectrum of the CH3I- anion: Rare gas cluster mediated synthesis of an ion-radical complex

We report the preparation of the bare and argon-solvated anion of CH3I, and characterize this species using negative ion photoelectron spectroscopy at 3.495 eV. The photoelectron spectrum consists of a narrow band appearing 0 .11 +/- 0.02 eV above the binding energy of isolated iodide. Such behavior is similar to that displayed by iodide-(closed shell) solvent molecule comp lexes, indicating that photodetachment does not access the bound region of the CH3I potential. These observations suggest that CH3I- rearranges (after electron capture) to an ion-radical complex. We advance the hypothesis tha t this complex adopts a C-2 nu structure where the ion is hydrogen bonded t o the methyl radical. (J Am Soc Mass Spectrom 1999, 10, 810-814) (C) 1999 A merican Society for Mass Spectrometry.