18 research outputs found
Coverage Dependent Disorder–Order Transition of 2H-Tetraphenylporphyrin on Cu(111)
In this study, we investigate the
peculiar coverage dependent supramolecular
arrangement of 2H-tetraphenylporhpyrin (2HTPP) on Cu(111) with scanning
tunneling microscopy at room-temperature. At low coverage, “slow”
diffusion of individual 2HTPP molecules along the close-packed atomic
rows of the substrate is observed, and no supramolecular ordering
occurs. However, at higher coverage, the formation of ordered, checkerboard-like
domains is found, with two molecules per unit cell at different distances
from the surface. This behavior is attributed to a complex interplay
of site specific molecule–substrate interaction, mainly the
strong interaction between the iminic N atoms and Cu substrate atoms,
with intermolecular T-type and π–π interactions
Coverage Dependent Disorder–Order Transition of 2H-Tetraphenylporphyrin on Cu(111)
In this study, we investigate the
peculiar coverage dependent supramolecular
arrangement of 2H-tetraphenylporhpyrin (2HTPP) on Cu(111) with scanning
tunneling microscopy at room-temperature. At low coverage, “slow”
diffusion of individual 2HTPP molecules along the close-packed atomic
rows of the substrate is observed, and no supramolecular ordering
occurs. However, at higher coverage, the formation of ordered, checkerboard-like
domains is found, with two molecules per unit cell at different distances
from the surface. This behavior is attributed to a complex interplay
of site specific molecule–substrate interaction, mainly the
strong interaction between the iminic N atoms and Cu substrate atoms,
with intermolecular T-type and π–π interactions
Coverage Dependent Disorder–Order Transition of 2H-Tetraphenylporphyrin on Cu(111)
In this study, we investigate the
peculiar coverage dependent supramolecular
arrangement of 2H-tetraphenylporhpyrin (2HTPP) on Cu(111) with scanning
tunneling microscopy at room-temperature. At low coverage, “slow”
diffusion of individual 2HTPP molecules along the close-packed atomic
rows of the substrate is observed, and no supramolecular ordering
occurs. However, at higher coverage, the formation of ordered, checkerboard-like
domains is found, with two molecules per unit cell at different distances
from the surface. This behavior is attributed to a complex interplay
of site specific molecule–substrate interaction, mainly the
strong interaction between the iminic N atoms and Cu substrate atoms,
with intermolecular T-type and π–π interactions
Coverage Dependent Disorder–Order Transition of 2H-Tetraphenylporphyrin on Cu(111)
In this study, we investigate the
peculiar coverage dependent supramolecular
arrangement of 2H-tetraphenylporhpyrin (2HTPP) on Cu(111) with scanning
tunneling microscopy at room-temperature. At low coverage, “slow”
diffusion of individual 2HTPP molecules along the close-packed atomic
rows of the substrate is observed, and no supramolecular ordering
occurs. However, at higher coverage, the formation of ordered, checkerboard-like
domains is found, with two molecules per unit cell at different distances
from the surface. This behavior is attributed to a complex interplay
of site specific molecule–substrate interaction, mainly the
strong interaction between the iminic N atoms and Cu substrate atoms,
with intermolecular T-type and π–π interactions
Coverage Dependent Disorder–Order Transition of 2H-Tetraphenylporphyrin on Cu(111)
In this study, we investigate the
peculiar coverage dependent supramolecular
arrangement of 2H-tetraphenylporhpyrin (2HTPP) on Cu(111) with scanning
tunneling microscopy at room-temperature. At low coverage, “slow”
diffusion of individual 2HTPP molecules along the close-packed atomic
rows of the substrate is observed, and no supramolecular ordering
occurs. However, at higher coverage, the formation of ordered, checkerboard-like
domains is found, with two molecules per unit cell at different distances
from the surface. This behavior is attributed to a complex interplay
of site specific molecule–substrate interaction, mainly the
strong interaction between the iminic N atoms and Cu substrate atoms,
with intermolecular T-type and π–π interactions
Abrupt Coverage-Induced Enhancement of the Self-Metalation of Tetraphenylporphyrin with Cu(111)
Using
X-ray photoelectron spectroscopy (XPS) and scanning tunneling
microscopy (STM), the coverage-dependent self-metalation of 2<i>H</i>-tetraphenylporphyrin (2HTPP) with Cu on Cu(111) at 400
K has been studied. At low coverages the porphyrin molecules are adsorbed
as isolated molecules, and the rate of metalation is slow. As the
coverage is increased beyond ∼0.36 molecules/nm<sup>2</sup>, a supramolecular checkerboard structure is formed, with every second
molecule slightly elevated above the surface. The appearance of this
checkerboard structure coincides with a dramatic increase in the rate
of metalation. This enhancement is attributed to a smaller activation
barrier for the elevated molecules, which have an internal conformation
similar to that of the free molecule, whereas the less reactive molecules
in direct contact with the surface are strongly distorted
Role of Specific Intermolecular Interactions for the Arrangement of Ni(II)-5, 10, 15, 20-Tetraphenyltetrabenzoporphyrin on Cu(111)
Towards the engineering of molecular nanostructures: local anchoring and functionalization of porphyrins on model-templates
Reversible thermally induced phase transition in ordered domains of Co(II)-5,10,15,20-tetrakis-(3,5-di-tert-butylphenyl)-porphyrin on Cu(111)
Role of Specific Intermolecular Interactions for the Arrangement of Ni(II)-5, 10, 15, 20-Tetraphenyltetrabenzoporphyrin on Cu(111)
We have studied the coverage-dependent
adsorption behavior of Ni(II)-5,10,15,20-tetraphenyltetrabenzoporphyrin
on Cu(111) by scanning tunneling microscopy (STM) at room temperature.
At medium coverages, the molecules self-assemble into two-dimensional
islands, due to mutual stabilization through intermolecular interactions.
Altogether, three different supramolecular arrangements coexist at
low-to-medium coverages. On the basis of high-resolution STM images
and density functional theory calculations, models for the three arrangements
and the corresponding intramolecular conformations of the individual
molecules are proposed. The observed polymorphism is attributed to
a complex interplay of specific T-type and π–π
stacking interactions between the phenyl groups. For Ni(II)-<i>meso</i>-tetrakis (4-<i>tert</i>-butylphenyl) benzoporphyrin,
in which the aromatic periphery is modified by the attachment of <i>tert</i>-butyl groups, only one supramolecular arrangement on
Cu(111) is found. This difference highlights the fact that the choice
of peripheral ligands of the porphyrin derivatives plays an important
role in the fabrication and tailoring of functional molecular architectures