Surface-Confined Macrocyclization via Dynamic Covalent Chemistry

• Published in: ACS nano Vol. 14; no. 3; pp. 2956 - 2965
• Main Authors: Fu, Chaoying, Mikšátko, Jiří, Assies, Lea, Vrkoslav, Vladimír, Orlandi, Silvia, Kalbáč, Martin, Kovaříček, Petr, Zeng, Xiaobin, Zhou, Boping, Muccioli, Luca, Perepichka, Dmitrii F, Orgiu, Emanuele
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 24.03.2020
• Subjects: dynamic covalent chemistry; macrocycle; on-surface synthesis; scanning tunneling microscopy; density functional theory; molecular dynamics simulation
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.9b07671

Surface-confined synthesis is a promising approach to build complex molecular nanostructures including macrocycles. However, despite the recent advances in on-surface macrocyclization under ultrahigh vacuum, selective synthesis of monodisperse and multicomponent macrocycles remains a challenge. Here, we report on an on-surface formation of [6 + 6] Schiff-base macrocycles via dynamic covalent chemistry. The macrocycles form two-dimensional crystalline domains on the micrometer scale, enabled by dynamic conversion of open-chain oligomers into well-defined ∼3.0 nm hexagonal macrocycles. We further show that by tailoring the length of the alkyl substituents, it is possible to control which of three possible productsoligomers, macrocycles, or polymerswill form at the surface. In situ scanning tunneling microscopy imaging combined with density functional theory calculations and molecular dynamics simulations unravel the synergistic effect of surface confinement and solvent in leading to preferential on-surface macrocyclization.