Highly stereospecific on-surface dimerization into bishelicenes: Topochemical Ullmann coupling of bromohelicene on Au(111)

0582135 - FZÚ 2024 RIV DE eng J - Journal Article
Voigt, J. - Martin, K. - Neziri, E. - Baljozović, M. - Wäckerlin, C. - Avarvari, N. - Ernst, Karl-Heinz
Highly stereospecific on-surface dimerization into bishelicenes: Topochemical Ullmann coupling of bromohelicene on Au(111).
Chemistry - A European Journal. Roč. 29, č. 28 (2023), č. článku e202300134. ISSN 0947-6539. E-ISSN 1521-3765
R&D Projects: GA ČR(CZ) GX20-13692X; GA ČR(CZ) GF21-17194L
Institutional support: RVO:68378271
Keywords : chirality * helicenes * on-surface chemistry * polyaromatic hydrocarbons * scanning tunneling microscopy
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 4.3, year: 2022
Method of publishing: Open access

The on-surface dimerization into bis(hexahelicene) on a gold(111) surface has been studied by means of scanning tunneling microscopy and time-of-flight secondary mass spectrometry. C!C Ullmann coupling of (rac)-2-bromohexahelicene leads to formation of the (M,M)- and (P,P)- diastereomers of 2,2’-bis(hexahelicene), whilst formation of the (M,P)-diastereomer is not observed. Upon cooling, the bis(hexahelicene) aggregates into an ordered two-dimensional lattice with partly randomly distributed enantiomers. The highly specific diastereomeric coupling is explained by the surface alignment of educt in combination with the strong steric overcrowding in a possible surface-confined (M,P)-product.

Permanent Link: https://hdl.handle.net/11104/0350210