Physical Chemistry Chemical Physics, 12 (2010) 8815–8821
A novel approach of identifying metal atoms within a metal-organic surface coordination network using scanning tunnelling microscopy (STM) is presented. The Cu adatoms coordinated in the porous surface network of 1,3,8,10-tetraazaperopyrene (TAPP) molecules on a Cu(111) surface give rise to a characteristic electronic resonance in STM experiments. Using density functional theory calculations, we provide strong evidence that this resonance is a fingerprint of the interaction between the molecules and the Cu adatoms. We also show that the bonding of the Cu adatoms to the organic exodentate ligands is characterised by both the mixing of the nitrogen lone-pair orbitals of TAPP with states on the Cu adatoms and the partial filling of the lowest unoccupied molecular orbital (LUMO) of the TAPP molecule. Furthermore, the key interactions determining the surface unit cell of the network are discussed.
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aSurface Science Research Centre, University of Liverpool bNCCR Nanoscale Science and Department of Physics, University of Basel cAnorganisch-Chemisches Institut, Universität Heidelberg dLaboratory for Micro- and Nanotechnology, Paul-Scherrer-Institute eDepartment of Applied Physics, Chalmers University of Technology fZernike Institute for Advanced Materials, University of Groningen gCentre d'Investigaciò en Nanociència i Nanotecnologia CIN2 (CSIC-ICN), Esfera UAB hDonostia International Physics Center, San Sebastian
