title: Stop-Frame Filming and Discovery of Reactions at the Single-Molecule Level by Transmission Electron Microscopy.
abstract: We report an approach, named chemTEM, to follow chemical transformations at the single-molecule level with the electron beam of a transmission electron microscope (TEM) applied as both a tunable source of energy and a sub-angstrom imaging probe. Deposited on graphene, disk-shaped perchlorocoronene molecules are precluded from intermolecular interactions. This allows monomolecular transformations to be studied at the single-molecule level in real time and reveals chlorine elimination and reactive aryne formation as a key initial stage of multistep reactions initiated by the 80 keV e-beam. Under the same conditions, perchlorocoronene confined within a nanotube cavity, where the molecules are situated in very close proximity to each other, enables imaging of intermolecular reactions, starting with the Diels-Alder cycloaddition of a generated aryne, followed by rearrangement of the angular adduct to a planar polyaromatic structure and the formation of a perchlorinated zigzag nanoribbon of graphene as the final product. ChemTEM enables the entire process of polycondensation, including the formation of metastable intermediates, to be captured in a one-shot "movie". A molecule with a similar size and shape but with a different chemical composition, octathio[8]circulene, under the same conditions undergoes another type of polycondensation via thiyl biradical generation and subsequent reaction leading to polythiophene nanoribbons with irregular edges incorporating bridging sulfur atoms. Graphene or carbon nanotubes supporting the individual molecules during chemTEM studies ensure that the elastic interactions of the molecules with the e-beam are the dominant forces that initiate and drive the reactions we image. Our ab initio DFT calculations explicitly incorporating the e-beam in the theoretical model correlate with the chemTEM observations and give a mechanism for direct control not only of the type of the reaction but also of the reaction rate. Selection of the appropriate e-beam energy and control of the dose rate in chemTEM enabled imaging of reactions on a time frame commensurate with TEM image capture rates, revealing atomistic mechanisms of previously unknown processes.
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.|Institute of Process Research and Development, School of Chemistry, University of Leeds , Leeds LS2 9JT, United Kingdom.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Chamberlain
authors.affiliation: Central Facility of Electron Microscopy, Electron Microscopy Group of Materials Science, University of Ulm , 89081 Ulm, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Biskupek
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Stephen T
authors.identifier: 0000-0001-7322-5508
authors.initials: ST
authors.lastname: Skowron
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Markevich
authors.affiliation: Central Facility of Electron Microscopy, Electron Microscopy Group of Materials Science, University of Ulm , 89081 Ulm, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Kurasch
authors.affiliation: Faculty of Physics, University of Bielefeld , 33615 Bielefeld, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Reimer
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Kate E
authors.initials: KE
authors.lastname: Walker
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Graham A
authors.initials: GA
authors.lastname: Rance
authors.affiliation: Center for Advancing Electronics Dresden (cfaed) and Department of Chemistry and Food Chemistry, Technische Universitaet Dresden , 01069 Dresden, Germany.
authors.forename: Xinliang
authors.initials: X
authors.lastname: Feng
authors.affiliation: Max Planck Institute for Polymer Research , Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Klaus
authors.identifier: 0000-0001-6630-8786
authors.initials: K
authors.lastname: Müllen
authors.affiliation: Institute of Physical Chemistry, Friedrich Schiller University Jena , Lessingstraße 10, 07743 Jena, Germany.
authors.forename: Andrey
authors.initials: A
authors.lastname: Turchanin
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Maria A
authors.identifier: 0000-0002-3543-6416
authors.initials: MA
authors.lastname: Lebedeva
authors.affiliation: Department of Chemistry, Moscow M.V. Lomonosov State University , Leninskiye Gory, Moscow 119992, Russia.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Majouga
authors.affiliation: Department of Chemistry, Moscow M.V. Lomonosov State University , Leninskiye Gory, Moscow 119992, Russia.
authors.forename: Valentin G
authors.identifier: 0000-0001-9162-5169
authors.initials: VG
authors.lastname: Nenajdenko
authors.affiliation: Central Facility of Electron Microscopy, Electron Microscopy Group of Materials Science, University of Ulm , 89081 Ulm, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Kaiser
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Elena
authors.identifier: 0000-0002-9910-7603
authors.initials: E
authors.lastname: Besley
authors.affiliation: School of Chemistry, University of Nottingham , Nottingham NG7 2RD, United Kingdom.
authors.forename: Andrei N
authors.identifier: 0000-0001-7738-4098
authors.initials: AN
authors.lastname: Khlobystov
keywords: carbon nanotube; graphene; single-molecule imaging; single-molecule reaction; transmission electron microscopy