Adam Q. Shaw

Pairs and heptamers of C70 molecules ordered via PTCDI-melamine supramolecular networks

In this paper, we report on the use of two PTCDI-melamine supramolecular networks on Au(111) to trap C70 molecules. The different supramolecular networks were formed by changing the postannealing temperature after molecular deposition. We observed, using scanning tunneling microscopy, that the deposition of C70 onto a PTCDI melamine network with parallelogram cavities results in the long-range ordering of paired C70, whereas the deposition of C70 molecules onto a PTCDI-melamine honeycomb network results in the trapping of C70 heptamers.

Epitaxial ordering of a perylenetetracarboxylic diimide-melamine supramolecular network driven by the Au(111)-(22×3) reconstruction

Substrate mediated ordering and intermolecular interactions are used to create a long-range supramolecular network of perylenetetracarboxylic diimide and melamine on a reconstructed Au(111)-(22×3) surface. Scanning tunneling microscopy reveals that the network is composed of a succession of double width honeycomb cell rows separated by a more closely packed row of parallelograms. This periodicity of the supramolecular configuration matches that of the reconstructed gold substrate allowing an epitaxial relationship between network and substrate reconstruction.

Grating of single Lu@C-82 molecules using supramolecular network

A supramolecular grating of single Lu@C(82) molecules was obtained by depositing Lu@C(82) molecules onto a room temperature PTCDI-melamine network.

Designing Optoelectronic Properties by On-Surface Synthesis: Formation and Electronic Structure of an Iron–Terpyridine Macromolecular Complex

Supramolecular chemistry protocols applied on surfaces offer compelling avenues for atomic-scale control over organic-inorganic interface structures. In this approach, adsorbate-surface interactions and two-dimensional confinement can lead to morphologies and properties that differ dramatically from those achieved via conventional synthetic approaches. Here, we describe the bottom-up, on-surface synthesis of one-dimensional coordination nanostructures based on an iron (Fe)-terpyridine (tpy) interaction borrowed from functional metal-organic complexes used in photovoltaic and catalytic applications. Thermally activated diffusion of sequentially deposited ligands and metal atoms and intraligand conformational changes lead to Fe-tpy coordination and formation of these nanochains. We used low-temperature scanning tunneling microscopy and density functional theory to elucidate the atomic-scale morphology of the system, suggesting a linear tri-Fe linkage between facing, coplanar tpy groups. Scanning tunneling spectroscopy reveals the highest occupied orbitals, with dominant contributions from states located at the Fe node, and ligand states that mostly contribute to the lowest unoccupied orbitals. This electronic structure yields potential for hosting photoinduced metal-to-ligand charge transfer in the visible/near-infrared. The formation of this unusual tpy/tri-Fe/tpy coordination motif has not been observed for wet chemistry synthetic methods and is mediated by the bottom-up on-surface approach used here, offering pathways to engineer the optoelectronic properties and reactivity of metal-organic nanostructures.