Iodine passivation facilitates on-surface synthesis of robust regular conjugated two-dimensional organogold networks on Au(111)

• Published in: Nanoscale horizons 2024-05, Vol.9 (6), p.142-151
• Main Authors: Badami-Behjat, Arash, Galeotti, Gianluca, Gutzler, Rico, Pastoetter, Dominik L, Heckl, Wolfgang M, Feng, Xinliang, Lackinger, Markus
• Format: Article
• Language: English
• Subjects: Carbon; Conjugation; Coupling; Density functional theory; Error correction; High vacuum; Iodine; Networks; Scanning tunneling microscopy; Thermal stability
• ISSN: 2055-6756; 2055-6764; 2055-6764
• DOI: 10.1039/d3nh00496a

Two-dimensional conjugated organogold networks with anthra-tetrathiophene repeat units are synthesized by thermally activated debrominative coupling of 2,5,9,12-tetrabromoanthra[1,2- b :4,3- b ′:5,6- b ′′:8,7- b ′′′]tetrathiophene (TBATT) precursor molecules on Au(111) surfaces under ultra-high vacuum (UHV) conditions. Performing the reaction on iodine-passivated Au(111) surfaces promotes formation of highly regular structures, as revealed by scanning tunneling microscopy (STM). In contrast, coupling on bare Au(111) surfaces results in less regular networks due to the simultaneous expression of competing intermolecular binding motifs in the absence of error correction. The carbon-Au-carbon bonds confer remarkable robustness to the organogold networks, as evidenced by their high thermal stability. In addition, as suggested by density functional theory (DFT) calculations and underscored by scanning tunneling spectroscopy (STS), the organogold networks exhibit a small electronic band gap in the order of 1.0 eV due to their high π-conjugation. Regular and robust 2D conjugated organogold networks with anthra-tetrathiophene repeat units are synthesized by debrominative coupling on iodine-passivated Au(111). Dynamic error correction becomes feasibly through iodine-induced bond reversibility.