title: Corrole isomers: intrinsic gas-phase shapes via traveling wave ion mobility mass spectrometry and dissociation chemistries via tandem mass spectrometry.
abstract: Corrole and four of its isomers with subtle structural changes promoted by exchange of nitrogen and carbon atoms in the corrole ring have been studied by traveling wave ion mobility mass spectrometry and collision induced dissociation experiments. Significant differences in shapes and charge distributions for their protonated molecules were found to lead to contrasting gas phase mobilities, most particularly for corrorin, the most "confused" isomer. Accordingly, corrorin was predicted by B3LYP/6-31g(d,p) and collisional cross section calculations to display the most compact tri-dimensional structure, whereas NCC4 and corrole were found to be the most planar isomers. Better resolution between the corrole isomers was achieved using the more polarizable and massive CO(2) as the drift gas. Sequential losses of HF molecules were found to dominate the dissociation chemistry of the protonated molecules of these corrole isomers, but their unique structures caused contrasting labilities towards CID, whereas NCC4 showed a peculiar and structurally diagnostic loss of NH(3), allowing its prompt differentiation from the other isomers.
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas - UNICAMP, 13084-970 Campinas, SP, Brazil.
authors.forename: Maíra
authors.initials: M
authors.lastname: Fasciotti
authors.forename: Alexandre F
authors.initials: AF
authors.lastname: Gomes
authors.forename: Fabio C
authors.initials: FC
authors.lastname: Gozzo
authors.forename: Bernardo A
authors.initials: BA
authors.lastname: Iglesias
authors.forename: Gilberto F
authors.initials: GF
authors.lastname: de Sá
authors.forename: Romeu J
authors.initials: RJ
authors.lastname: Daroda
authors.forename: Motoki
authors.initials: M
authors.lastname: Toganoh
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Furuta
authors.forename: Koiti
authors.initials: K
authors.lastname: Araki
authors.forename: Marcos N
authors.initials: MN
authors.lastname: Eberlin