title: A Two-Dimensional Polymer Synthesized through Topochemical [2 + 2]-Cycloaddition on the Multigram Scale.
abstract: The single-crystal-to-single-crystal (scsc) synthesis of a 2D polymer based on photochemically triggered [2 + 2]-cycloaddition is reported. Both monomer and polymer single crystals are analyzed by X-ray diffraction, which is the first case of a scsc two-dimensional polymerization based on this cycloaddition and the third ever case for a scsc synthesis of a 2D polymer. The product crystals at quantitative conversion are wet-exfoliated under mild conditions and afford countless features that are single and double layers as judged by their AFM heights of hAFM≈ 1.2 ± 0.5 and 2.2 ± 0.5 nm, respectively. The X-ray-structure-based molecular weight of the 2D polymers and their degree of polymerization per μm2are M = 360 MDa and Pn= 464 900, respectively. The sheet size is on the order of 5 × 5 μm2.
authors.affiliation: Institute of Polymers and ‡X-ray Platform, Department of Materials, Swiss Federal Institute of Technology, ETH Zürich , Vladimir Prelog-Weg 5, 8093 Zürich, Switzerland.
authors.forename: Ralph Z
authors.initials: RZ
authors.lastname: Lange
authors.affiliation: Institute of Polymers and ‡X-ray Platform, Department of Materials, Swiss Federal Institute of Technology, ETH Zürich , Vladimir Prelog-Weg 5, 8093 Zürich, Switzerland.
authors.forename: Gregor
authors.initials: G
authors.lastname: Hofer
authors.affiliation: Institute of Polymers and ‡X-ray Platform, Department of Materials, Swiss Federal Institute of Technology, ETH Zürich , Vladimir Prelog-Weg 5, 8093 Zürich, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Weber
authors.affiliation: Institute of Polymers and ‡X-ray Platform, Department of Materials, Swiss Federal Institute of Technology, ETH Zürich , Vladimir Prelog-Weg 5, 8093 Zürich, Switzerland.
authors.forename: A Dieter
authors.identifier: 0000-0001-9975-9831
authors.initials: AD
authors.lastname: Schlüter