Figure 4.

Disassembly of [Ring_M]⁻, [Ph_M + A]⁺ and [Am_M + A]⁺ (A⁺ = H⁺, Na⁺) including fragmentation channels, determining stability factors, and CCS_N2 (Cr: green, M: black, N: blue, Rest: white). Top: suggested loss of pivalic acid adjacent to M for the protonated species [Ph_M + H]⁺ and [Am_M + H]⁺. Center: predicted conformations of [Ring_M]⁻ fragments 1–3 involving interconverting helical structures E and closed rings C. CCS_N2 values are given for M = Mn^II. ATD for other d-metals are found in the Supporting Information and the supplementary data set. Bottom: observed slipping mechanism for the sodiated forms [Ph_M + Na]⁺ and [Am_M + Na]⁺ including ring widening, showing the intact ring fragments 4–7 in the activated IM-MS spectra.