Coverage-Dependent Structural Transformation of Cyano-Functionalized Porphyrin Networks on Au(111) via Addition of Cobalt Atoms

Autor: Meike Stöhr, Nico Schmidt, Brian D Baker Cortés, Mihaela Enache
Přispěvatelé: Surfaces and Thin Films
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Journal of Physical Chemistry C, 123(32), 19681-19687. AMER CHEMICAL SOC
The Journal of Physical Chemistry. C, Nanomaterials and Interfaces
ISSN: 1932-7447
Popis: The self-assembly process of a cobalt-porphyrin derivative (Co-TCNPP) containing cyanophenyl substituents at all four meso positions on Au(111) was studied by means of scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) under ultrahigh vacuum conditions. Deposition of Co-TCNPP onto Au(111) gave rise to the formation of a close-packed H-bonded network, which was independent of coverage as revealed by STM and LEED. However, a coverage-dependent structural transformation took place upon the deposition of Co atoms. At monolayer coverage, a reticulated long-range ordered network exhibiting a distinct fourfold Co coordination was observed. By reduction of the molecular coverage, a second metal-organic coordination network (MOCN) was formed in coexistence with the fourfold Co-coordinated network, that is, a chevron structure stabilized by a simultaneous expression of H-bonding and threefold Co coordination. We attribute the coverage-dependent structural transformation to the in-plane compression pressure exerted by the molecules deposited on the surface. Our study shows that a subtle interplay between the chemical nature of the building blocks (molecules and metallic atoms) and molecular coverage can steer the formation of structurally different porphyrin-based MOCNs.
Databáze: OpenAIRE