L-Cysteine on Ag(111): A combined STM and X-ray spectroscopy study of anchorage and deprotonation

  • Autor:

    Fischer, S. / Papageorgiou, A. / Marschall, M. / Reichert, J. / Diller, K. / Klappenberger, F. / Allegretti, F. / Nefedov, A. / Wöll, C. / Barth, J. / (2012)
  • Quelle:

    J. Phys. Chem. C, 116, 20356-20362
  • Datum: 2012

  • Fischer, S. / Papageorgiou, A. / Marschall, M. / Reichert, J. / Diller, K. / Klappenberger, F. / Allegretti, F. / Nefedov, A. / Wöll, C. / Barth, J. / (2012): „L-Cysteine on Ag(111): A combined STM and X-ray spectroscopy study of anchorage and deprotonation“. In: J. Phys. Chem. C, 116, 20356-20362

Abstract

Thiols adsorbed on noble metals are prominent model systems for self-assembly and nanotechnology research. l-cysteine is the only proteinogenic amino acid containing a thiol group. A detailed knowledge of the interaction of this molecule with well-defined surfaces is essential to rationalize and advance interfacial amino acid self-assembly and the metal-mediated anchoring of proteins.

Here, we address the exemplary system l-cysteine on Ag(111) in UHV, examined by direct STM observations, synchrotron-based XPS, and NEXAFS. Following adsorption, the molecules build up a dense-packed layer of zwitterions, attached to the surface via their sulfur atom. Upon annealing to 390 K, the cysteine molecules undergo pronounced chemical and conformational transformation, leading to a more complex assembly, driven by the deprotonation of the ammonium group.

 

 

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