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O: Fachverband Oberflächenphysik

O 27: Organic/bio Molecules on Metal Surfaces III

O 27.4: Vortrag

Dienstag, 1. April 2014, 11:15–11:30, TRE Phy

Porphyrin metalation providing an example of a redox reaction facilitated by a surface reconstruction — •Jan Nowakowski¹, Christian Wäckerlin¹, Jan Girovsky¹, Dorota Siewert¹, Thomas A. Jung¹, and Nirmalya Ballav² — ¹PSI, Villigen, Switzerland — ²IISER, Pune, India

Recently, significant attention has been drawn to on-surface reactions [1], including on-surface redox chemistry [2], of which the metalation of free-base porphyrins is an interesting example [3, 4]. The on-surface metalation can be realized in three ways: (i) by picking up free heteroatoms from a surface [5]; (ii) by depositing metal atoms on top of molecules predeposited on an intert substrate (e.g. Au or Ag); or (iii) self-metalation, i.e. by coordination with atoms of a crystalline substrate. The temperature of on-surface metalation depends on the method chosen and on the element used [5]. We show [5] that, surprisingly, passivating a Cu(001) surface with an oxygen- surface reconstruction lowers the self-metalation temperature of 5,10,15,20-Tetraphenylporphin (2HTPP) from 450 K on native Cu(001) surface to 285 K on the oxygen-reconstructed Cu(001) surface. In the presented study X-Ray Photoelectron Spectroscopy (XPS) and Scanning Tunneling Microscopy (STM) methods have been used.

[1] C. Diaz et al., Science, 2009, 326, 832;

[2] D.-T. Pham et al., New J. Chem., 2006, 30, 1439;

[3] W. Auwärter et al., ChemPhysChem, 2007, 8, 250;

[4] J. M. Gottfried et al., J. Am. Chem. Soc., 2006, 128, 5644;

[5] J. Nowakowski et al., Chem. Commun., 2013, 49, 2347.