Unprecedented intact radical anions, closed shell anions, cluster ions, and traditional cations and radical cations by LIFDI-MS.

Abstract

Liquid injection field desorption ionization (LIFDI) proves the extraordinary softness of the ionization process combined with a convenient sample supply under the exclusion of moisture and air. LIFDI-mass spectrometry (MS) is used for organometallic and other seriously air-sensitive compounds forming intact ions without substantial fragmentation. Unprecedented molecular radical anions M^-• are presented along with well-known intact M^+• radical cations. Furthermore closed shell cations [C]⁺ and adduct ions like [M + H]⁺ or [M + Alkali]⁺ are gently transferred from the solid emitter surface into the gas phase. Anions [A]^- or [M - H]^- are accessible by LIFDI-MS at medium field strengths. Ion pairs [C]⁺[A]^- are separately detected by positive and negative mode LIFDI-MS, respectively. Here we give an overview of the different ion types accessible by LIFDI-MS. For the first time the field ionization/desorption of solar cell electron acceptor compounds is shown to deliver M^-• and M^2-• radical ions.