The densest iron coordination network based on carboxylate ligands
| Autor: | Gallego, José M., Trelka, Marta, Faraggi, Marisa N., Otero, Roberto, Arnau, Andrés, Miranda, Rodolfo |
|---|---|
| Rok vydání: | 2009 |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| Popis: | Trabajo presentado al "11th International Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures" celebrado en San Petersburgo del 3 al 7 de octubre del 2011.-- et al. Over the last decade there has been a tremendous effort in order to create new kinds of supramolecular organic nanostructures on surfaces. In particular, a lot of attention has been paid to 2D metal-organic coordination networks (MOCNs), with the idea of creating functional metallo-supramolecular arrays on surfaces which combine the properties of their constituent metal ions and ligands. Over the last decade there has been a tremendous effort in order to create new kinds of supramolecular organic nanostructures on surfaces. In particular, a lot of attention has been paid to 2D metal-organic coordination networks (MOCNs), with the idea of creating functional metallo-supramolecular arrays on surfaces which combine the properties of their constituent metal ions and ligands. Up to now, the molecular backbone of all the used organic ligands contains pi-systems, along with the metal-binding moieties, designated to promote a planar adsorption geometry that would enable the metal binding centers (carboxylate, cyano and pyridyl groups) to adopt the appropriate binding configuration. The introduction of these pi-systems leads, however, to steric restraints that prevent the metallic centers from coming too close from each other. This is a very severe limitation when collective magnetic response of the metal centers is sought. Here we report on a combined Scanning Tunneling Microscopy (STM), X-Ray Photoemission pectroscopy (XPS), X-Ray Absorption Spectroscopy (XAS), and Density Functional Theory (DFT) study showing the formation of a 2D iron oxalate net work on Cu(111) and Cu(100) surfaces. The network was grown by sequential sublimation of oxalic acid molecules and submonolayer amounts of iron on the self-assembled carboxylate islands, followed by a gentle annealing procedure to enable both components to mix. Our experiments allow us to conclude that, prior to the metal deposition, oxalic acid is fully deprotonated into oxalate and it is adsorbed flat on the surface. Iron deposition plus annealing leads to a nanoscale morphology made out of patches with a honeycomb structure and a periodicity of 0.77 nm, where the iron atoms occupy the nodes of the honeycomb network, and are thus separated by 0.45 nm, the shortest metal-metal center ever reported for a solid-supported 2D coordination network. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|