Anions [N(CH₂)₃]⁻ and [ON(CH₂)₂]⁻ are Stable in the Gas Phase, but Can They Be Charge Stripped to Form the Radicals N(CH₂)₃ and ON(CH₂)₂? A Joint Experimental and Theoretical Study

Abstract

Collision-induced activation of deprotonated trimethylamine N-oxide yields the two anions [N(CH(2))(3)](-) and [ON(CH(2))(2)](-) following losses of H(2)O and CH(4), respectively. These two anions decompose by minor losses of H(*) and H(2) when collisionally activated: no other fragmentations are noted. Calculations at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-31+G(d) level of theory indicate that these trigonal anions are stable, and should not rearrange following collisional activation. Collisional-induced charge stripping of the anions [N(CH(2))(3)](-) and [ON(CH(2))(2)](-), respectively, form N(CH(2))(3) and ON(CH(2))(2). Some of these neutrals are energised and undergo rearrangement and dissociation. From a consideration of experiment and theory, it is proposed (i) that energised N(CH(2))(3) may cyclise to form the 1-aziridinylcarbinyl radical. This species may ring open to CH(2)=NCH(2)CH(2) which then decomposes to CH(2)N and C(2)H(4) and (ii) energised ON(CH(2))(2) may undergo OC cyclisation followed by ring opening to energised CH(2)=NCH(2)O which may fragment to yield CH(2)N and CH(2)O.