On-surface porphyrin transmetalation with Pb/Cu redox exchange. Issue 31 (22nd July 2021)

• Record Type: Journal Article
• Authors: Herritsch, Jan; Kachel, Stefan R.; Fan, Qitang; Hutter, Mark; Heuplick, Lukas J.; Münster, Florian; Gottfried, J. Michael
• Is Part Of: Nanoscale. Volume 13:Issue 31(2021)
• Page Start: 13241
• Page End: 13248
• Publication Date: 2021-07-22
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d1nr04180k
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Metal complexes at surfaces and interfaces are relevant in catalysis, sensors, and organic electronics. Metal centers in these complexes can easily be replaced by surface metal atoms, as was observed for a Pb porphyrin complex on a Cu surface. Abstract : Metal complexes at surfaces and interfaces play an important role in many areas of modern technology, including catalysis, sensors, and organic electronics. An important aspect of these interfaces is the possible exchange of the metal center, because this reaction can drastically alter the properties of the metal complex and thus of the interface. Here, we demonstrate that such metal exchange reactions are indeed possible and can proceed already at moderate temperatures even in the absence of solvents. Specifically, we studied the redox transmetalation of a monolayer of lead(ii )-tetraphenylporphyrin (PbTPP) with copper from a Cu(111) surface under ultrahigh-vacuum (UHV) conditions using multiple surface-sensitive techniques. Temperature-dependent X-ray photoelectron spectroscopy (XPS) reveals that the Pb/Cu exchange starts already below 380 K and is complete at 600 K. The identity of the reaction product, CuTPP, is confirmed by mass spectrometric detection in a temperature-programmed reaction (TPR) experiment. Scanning tunneling microscopy (STM) sheds light on the adsorbate structure of PbTPP at 300 K and uncovers the structural changes accompanying the transmetalation and side-reactions of the phenyl substituents. Moreover, individual free Pb atoms are observed as a product of the metal exchange.