Abstract
On‐surface synthesis is emerging as a highly rational bottom‐up methodology for the synthesis of molecular structures that are unattainable or complex to obtain by wet chemistry. Here, oligomers of meta‐polyaniline, a known ferromagnetic polymer, were synthesized from para‐aminophenol building‐blocks via an unexpected and highly specific on‐surface formal 1,4 Michael‐type addition at the meta position, driven by the reduction of the aminophenol molecule. We rationalize this dehydrogenation and coupling reaction mechanism with a combination of in situ scanning tunneling and non‐contact atomic force microscopies, high‐resolution synchrotron‐based X‐ray photoemission spectroscopy and first‐principles calculations. This study demonstrates the capability of surfaces to selectively modify local molecular conditions to redirect well‐established synthetic routes, such as Michael coupling, towards the rational synthesis of new covalent nanostructures.
Highlights
Quinone and quinone imines in general, and 1,4-benzoquinone monoimine in particular, are very useful building blocks for the synthesis of a wide variety of compounds,[1] from natural products to polymers, with a broad range of applications
We show that the unique reaction pathway induced by the Pt(111) surface leads to the formation of linear meta-polyaniline (m-PANI) oligomers from a precursor monomer functionalized at para positions (p-AP)
We report an unprecedented on-surface driven formal Michael-coupling leading to the formation of meta-polyaniline oligomers on Pt(111) surfaces directly from p-aminophenol precursors, which we investigate using advanced scanning probe microscopies and electron spectroscopies, combined with theoretical methods
Summary
Quinone and quinone imines in general, and 1,4-benzoquinone monoimine in particular, are very useful building blocks for the synthesis of a wide variety of compounds,[1] from natural products to polymers, with a broad range of applications. Conjugated polymers such as PANI are a family of polymers that have attracted huge scientific and technological attention during the last decade.[5,6,7] The emeraldine base form is generally regarded as the most useful, since it becomes electrically conducting upon simple protonation of the imine nitrogen atoms with an acid. This work is a clear example demonstrating that chemical routes that are complex or inefficient in solution-based chemistry can be accomplished via on-surface chemistry, opening the door to new approaches for the synthesis of defined supramolecular structures
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
