title: Photooxygenation and gas-phase reactivity of multiply threaded pseudorotaxanes.
abstract: The solution-phase photooxygenation of multiply threaded crown/ammonium pseudorotaxanes containing anthracene spacers is monitored by electrospray ionization Fourier-transform ion-cyclotron-resonance (ESI-FTICR) mass spectrometry. The oxygenated pseudorotaxanes are mass-selected and fragmented by infrared multiphoton dissociation (IRMPD) and/or collision-induced dissociation (CID) experiments and and their behavior compared to that of the non-oxygenated precursors. [4+2]Cycloreversion reactions lead to the loss of O2, when no other reaction channel with competitive energy demand is available. Thus, the release of molecular oxygen can serve as a reference reaction for the energy demand of other fragmentation reactions such as the dissociation of the crown/ammonium binding motifs. The photooxygenation induces curvature into the initially planar anthracene and thus significantly changes the geometry of the divalent, anthracene-spacered wheel. This is reflected in ion-mobility data. Coulomb repulsion in multiply charged pseudorotaxanes assists the oxygen loss as the re-planarization of the anthracene increases the distance between the two charges.
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.
authors.forename: Karol
authors.initials: K
authors.lastname: Nowosinski
authors.affiliation: Fritz Haber Institute of the Max Planck Society, Department of Molecular Physics, Faradayweg 4-6, 14195, Berlin, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Warnke
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.|Fritz Haber Institute of the Max Planck Society, Department of Molecular Physics, Faradayweg 4-6, 14195, Berlin, Germany.
authors.forename: Kevin
authors.initials: K
authors.lastname: Pagel
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.|Stratingh Institute for Chemistry, Rijksuniversiteit Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
authors.forename: Dávid
authors.initials: D
authors.lastname: Komáromy
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.|Department of Chemistry, South University of Science and Technology of China (SUSTC), No.1088 Xueyuan Blvd, Nanshan District, Shenzhen, 518055, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Schalley
keywords: (pseudo)rotaxanes; ion mobility mass spectrometry; multivalency; photooxygenation; self-assembly; self-sorting