On-surface reactions in ultrahigh vacuum

The possibility to build up complex nanostructures by self-assembly and subsequent chemical connection of single molecular building blocks in a specific manner (bottom-up principle) has gained great importance in the field of modern nanotechnology. The carrier surfaces used for this purpose enable the preparation of monomolecular thin polymeric structures on the given surfaces. Notably, the surface can be regarded as a new reaction medium in modern synthesis and the so-called on-surface chemistry provides the potential for the formation of two-dimensional macro-molecules. Moreover, new reactions have been discovered that are not accessible with classical methods using solvent-based or gas phase chemistry.

For several years, the Studer group in close collaboration with colleagues from the physics department (mainly Prof. H. Fuchs) has been successfully working in the field of on-surface chemistry.

The know-how of the Münster chemists enables the design and synthesis of the needed molecular building blocks according to the desired requirements. Specific introduction of functional groups into the chosen monomer entities allows to control the target on-surface reactions and to influence the physical properties of the generated polymeric structures.

Following this approach, the Studer/Fuchs working groups in joint efforts were able to establish new reactions like carbene coupling for on-surface polymerization. The successfully generated polymeric structures were investigated by scanning tunneling microscopy with molecular resolution. For complete structure elucidation, nc-AFM and XPS techniques were applied in collaboration with the Mönig group. Along these lines, unexpected and up to now unknown reactions like the nitrile dimerization were discovered and the mechanism was investigated. Also the different reaction behavior of alkynes with respect to the surface coverage was part of recent works.

Schematic presentation and STM/nc-AFM images of a) the on-surface (trans-)formation of carbenes on Au(111) and Cu(111),[2] b) the dimerization of nitriles and the cyclization of o,o’-dinitriles on Au(111),[X] and c) the reactivity of alkynes at different surface coverage on Ag(111).[X]
Schematic presentation and STM/nc-AFM images of a) the on-surface (trans-)formation of carbenes on Au(111) and Cu(111),[2] b) the dimerization of nitriles and the cyclization of o,o’-dinitriles on Au(111),[X] and c) the reactivity of alkynes at different surface coverage on Ag(111).[X]
© A. Studer
  1. Intermolecular coupling and intramolecular cyclization of aryl nitriles on Au(111)
    Klaasen H, Liu L, Gao H, Viergutz L, Held P, Knecht T, Meng X, Börner M C, Barton D, Amirjalayer S, Neugebauer J, Studer A, Fuchs H. Chem. Commun. 55, 11611-11614 (2019)
  2. Reaction selectivity in on-surface chemistry by surface coverage control - alkyne dimerization versus alkyne trimerization
    Klaasen H, Liu L, Meng X, Held P -A, Gao P -A, Barton D, Mück-Lichtenfeld C, Neugebauer J, Fuchs H, Studer A. Chem. Eur. J. 24, 15303-15308 (2018)
  3. α-Diazo ketones in on-surface chemistry
    Liu L, Klaasen H, Timmer A, Gao H -Y, Barton D, Mönig H, Neugebauer J, Fuchs H, Studer A. J. Am. Chem. Soc. 140, 6000-6005 (2018)
  4. Intermolecular on-surface σ-bond metathesis
    Gao H -Y, Held P -A, Amirjalayer S, Liu L, Timmer A, Schirmer B, Arado O D, Mönig H, Mück-Lichtenfeld C, Neugebauer J, Studer A, Fuchs H. J. Am. Chem. Soc. 139, 7012-7019 (2017)
  5. Formation of organometallic intermediate states in on-surface ullmann couplings
    Barton D, Gao H -Y, Held P -A, Studer A, Fuchs H, Doltsinis N L, Neugebauer J.
    Chem. Eur. J. 23, 6190-6197 (2017)
  6. Covalent-bond formation via on-surface chemistry
    Held P -A, Fuchs H, Studer A. Chem. Eur. J. 23, 5874-5892 (2017)
  7. Understanding molecular self-assembly of a diol compound by considering competitive interactions
    Arado O D, Luft M, Mönig H, Held P -A, Studer A, Amirjalayer S, Fuchs H. Phys. Chem. Chem. Phys. 18, 27390-27395 (2016)
  8. On-surface domino reactions: glaser coupling and dehydrogenative coupling of a biscarboxylic acid to form polymeric bisacylperoxide
    Held P A, Gao H -Y, Liu L, Mück-Lichtenfeld C, Timmer A, Mönig H, D Barton, Neugebauer J, Fuchs H, Studer A. Angew. Chem. Int. Ed. 55, 9777-9782 (2016); Angew. Chem. 128, 9929–9934 (2016)
  9. In-plane van der waals interactions of molecular self-assembly monolayer
    Gao H -Y, Wagner H, Held P -A, Du S, Gao H -J, Studer A, Fuchs H. Appl. Phys. Lett. 106, 081606-1-5 (2015)
  10. On-surface reductive coupling of aldehydes on Au(111)
    Arado O A, Mönig H, Franke J -H, Timmer A, Held P -A, Studer A, Fuchs H. Chem. Commun. 51, 4887-4890 (2015)
  11. Decarboxylative polymerization of 2,6-naphthalenedicarboxylic acid at surfaces
    Gao H -Y, Held P A, Knor M, Mück-Lichtenfeld C, Neugebauer J, Studer A, Fuchs H. J. Am. Chem. Soc. 136, 9658–9663 (2014)
  12. Photochemical glaser coupling at metal surfaces
    Gao H -Y, Zhong D, Mönig H, Wagner H, Held P A, Timmer A, Studer A, Fuchs H. J. Phys. Chem. C 118, 6272–6277 (2014)
  13. On-Surface Domino Reactions: Glaser Coupling and Dehydrogenative Coupling of a Biscarboxylic Acid To Form Polymeric Bisacylperoxides
         Held P A, Gao H -Y, Liu L, Mück-Lichtenfeld C, Timmer A, Mönig H, D Barton, Neugebauer J, Fuchs H, Studer A. Angew. Chem. Int. Ed. 55, 9777-9782 (2016); Angew. Chem. 128, 9929–9934 (2016)
  14. The effect of metal surfaces in on-surface glaser-coupling
    Gao H -Y, Franke J -H, Wagner, Zhong D, Held P -A, Studer A, Fuchs H.  J. Phys. Chem. C 117, 18595–18602 (2013)
  15. Glaser coupling at metal surfaces
    Gao H -Y, Wagner H, Zhong D, Franke J -H, Studer A, Fuchs H. Angew. Chem. Int. Ed. 52, 4024-4028 (2013); Angew. Chem. 125, 4116–4120 (2013)