Charge-State-Dependent Fragmentation of [2.2]Based Metallosupramolecular Cyclic Helicates in the Gas Phase

Chempluschem. 2020 Nov;85(11):2528-2533. doi: 10.1002/cplu.202000697.

Abstract

A detailed mass-spectrometric study provides insight into the gas-phase fragmentation pathways of a cyclic helicate selectively built from four iron(II) centers and six [2.2]cyclophane-based ligands through the subcomponent self-assembly approach. The charge state of the precursor ion, i. e., the number of triflate anions accompanying the metallo-supramolecular core, has a strong influence on the observed fragmentations. The triply charged ion shows loss of a neutral ligand whereas ions of higher charge fragment by up to three different charge-separating pathways to minimize the charge density of the ions. Additional subsequent fragmentations of highly charged fragment ions include redox processes as well as splitting of the unusual paracyclophane backbone.

Keywords: collision-induced dissociation; cyclic helicates; gas-phase fragmentation; self-assembly; supramolecular chemistry.