TY  - JOUR
AB  - On-surface synthesis in ultrahigh vacuum provides a promising strategy for creating thermally and chemically stable molecular structures at surfaces. The two-dimensional confinement of the educts, the possibility of working at higher (or lower) temperatures in the absence of solvent, and the templating effect of the surface bear the potential of preparing compounds that cannot be obtained in solution. Moreover, covalently linked conjugated molecules allow for efficient electron transport and are, thus, particularly interesting for future molecular electronics applications. When having these applications in mind, electrically insulating substrates are mandatory to provide sufficient decoupling of the molecular structure from the substrate surface. So far, however, on-surface synthesis has been achieved only on metallic substrates. Here we demonstrate the covalent linking of organic molecules on a bulk insulator, namely, calcite. We deliberately employ the strong electrostatic interaction between the carboxylate groups of halide-substituted benzoic adds and the surface calcium cations to prevent molecular desorption and to reach homolytic cleavage temperatures. This allows for the formation of aryl radicals and intermolecular coupling. By varying the number and position of the halide substitution, we rationally design the resulting structures, revealing straight lines, zigzag structures, and dimers, thus providing clear evidence for the covalent linking. Our results constitute an important step toward exploiting on-surface synthesis for molecular electronics and optics applications, which require electrically insulating rather than metallic supporting substrates.
DA  - 2011
DO  - 10.1021/nn2033192
KW  - on-surface synthesis
KW  - surface chemistry
KW  - covalent linking
KW  - bulk
KW  - insulator
KW  - noncontact atomic force microscopy
KW  - molecular electronics
LA  - eng
IS  - 10
M2  - 8420
PY  - 2011
SN  - 1936-0851
SP  - 8420-8425
T2  - ACS Nano
TI  - On-Surface Covalent Linking of Organic Building Blocks on a Bulk Insulator
UR  - https://nbn-resolving.org/urn:nbn:de:0070-pub-29138182
Y2  - 2024-11-22T02:36:46
ER  -