Zinc(II) Tetraphenylporphyrin on Ag(100) and Ag(111): Multilayer Desorption and Dehydrogenation

Ruggieri, Charles; Rangan, Sylvie; Bartynski, Robert; Galoppini, Elena

doi:10.1021/acs.jpcc.6b00159

Cited by 38 publications

(61 citation statements)

References 71 publications

(302 reference statements)

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“…The molecules appear then with slightly irregular shapes and regular self‐assembly is absent. A similar appearance was also observed for tetrapyrrole monolayers on Cu and Ag substrates which also dehydrogenated at the periphery by annealing to 500 – 640 K …”

Section: Resultssupporting

confidence: 76%

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On‐Surface Metalation and 2D Self‐Assembly of Pyrphyrin Molecules Into Metal‐Coordinated Networks on Cu(111)

Wäckerlin

Schnidrig

et al. 2016

Helvetica Chimica Acta

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The metalation of the tetradentate molecule pyrphyrin by copper substrate atoms on a Cu(111) surface is studied. Pyrphyrin, in contrast to porphyrin, consists of four fused pyridine groups instead of pyrrol groups. Using thermal desorption spectroscopy (TDS) and N 1s X‐ray photoelectron spectroscopy (XPS), we show that metalation of the monolayer of pyrphyrin with Cu atoms from the Cu(111) surface occurs at 377 K. The formation of an extended two‐dimensional (2D) network is observed with scanning tunneling microscopy (STM). A honeycomb‐like lattice of metalated pyrphyrin molecules is formed by intermolecular connection via the two cyano groups at the periphery of pyrphyrin as well as Cu adatoms. Dehydrogenation at the periphery of the molecule is observed during annealing at 520 K. The surface‐adsorbed metal‐pyrphyrin has the potential to serve as a molecular catalyst.

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Section: Resultssupporting

confidence: 76%

“…Such pyrolysis is a common feature for adsorbed hydrocarbons that are too tightly bound to the surface to become desorbed intact. This process has also been observed for monolayers of tetrapyrroles adsorbed on metal surfaces …”

Section: Resultssupporting

confidence: 62%

On‐Surface Metalation and 2D Self‐Assembly of Pyrphyrin Molecules Into Metal‐Coordinated Networks on Cu(111)

Wäckerlin

Schnidrig

et al. 2016

Helvetica Chimica Acta

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“…This issue also affects the C=O related features in XPS: an overall broadening is observed for the O 1 s spectrum as well as for the high BE component of the C 1 s spectrum. An important expected effect of the polymerization would be the delocalization of the electronic states near the Fermi level . HREELS spectra were thus recorded for higher energy losses (see SI Figure S4) and indeed revealed a bathochromic effect, indicative of a reduction of the HOMO‐LUMO gap ,…”

Section: Figurementioning

confidence: 92%

“…An important expected effect of the polymerization would be the delocalization of the electronic states near the Fermi level. [47][48][49][50] HREELS spectra were thus recorded for higher energy losses (see SI Figure S4) and indeed revealed a bathochromic effect, indicative of a reduction of the HOMO-LUMO gap. [29,51] To explore the dual reactivity of the precursor (Knoevenagel reaction and oxidative coupling) we performed further experiments on other silver surfaces with different crystallographic orientations.…”

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confidence: 99%

The Orientation of Silver Surfaces Drives the Reactivity and the Selectivity in Homo‐Coupling Reactions

et al. 2018

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Original reaction pathways can be explored in the on-surface synthesis approach where small aromatic precursors are confined to the surface of single crystal metals. The bis-indanedione molecule reacted with itself on silver surfaces in different ways, through a Knoevenagel reaction or an oxidative coupling, leading to the formation of a variety of new molecular compounds and covalently-linked 1D or 2D networks. Noteworthy, original reaction products were obtained that cannot be synthesized in traditional solvent-based chemistry. The lowest activation temperature for the homo-coupling reactions was found on the Ag(111) surface. The Ag(110) was highly selective in terms of coupling reaction type, while on Ag(100) the temperature could finely control the selectivity. The on-surface synthesis approach is shown here to be particularly efficient to produce original compounds in mild conditions, using activation temperatures as low as 200 °C. The different structures were characterized by scanning tunnelling microscopy (STM) together with X-ray photoelectron emission spectroscopy (XPS) and high-resolution electron energy loss spectroscopy (HREELS).

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“…Engineering of the opto-electronic properties of porphyrins thus continues to stimulate an intense research activity. Important modification to the porphyrin spectral response can be obtained for instance by functionalization [5,6], nano-structuration of extended porphyrin-based architectures [7,8] or adsorption on a substrate [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Electronic structure of tetra(4-aminophenyl)porphyrin studied by photoemission, UV–Vis spectroscopy and density functional theory

Giovanelli

Lee

Lacaze‐Dufaure

et al. 2017

Journal of Electron Spectroscopy and Related Phenomena

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao. b s t r a c tThe valence and conduction bands of a thin film of tetra(4-aminophenyl)porphyrin (TAPP) are investigated by direct and inverse photoemission as well as by comparison to density functional theory (DFT) calculations. By projecting the electronic eigenfunctions onto the molecular framework it was possible to interpret the origin of each spectroscopic feature. Although the majority of the photoemission spectrum is attributed to the unsubstituted tetraphenylporphyrin (TPP) parent molecule, several features are clearly due to the amino substitution. Substitution also has important consequences for the energy positions of the frontier orbitals and therefore on the low-energy electronic excitations. The measured electronic transport energy gap (E g = 1.85 eV) between the highest occupied molecular orbital (HOMO) and lowest unoccupied (LUMO) in TAPP is found to be significantly reduced with respect to TPP. Moreover, an increased energy separation between the two highest occupied states (HOMO and HOMO−1) is found both experimentally and by DFT calculations. Such evidence is attributed to an increased HOMO orbital destabilization due to an enhanced electron-donor character of the phenyl substituents upon amino functionalization. Finally, the above findings together with further time-dependent DFT calculations are used to interpret the effect of the amino groups on the UV-Vis absorption spectrum, namely an overall red-shift of the spectrum and remarkable intensity changes within the Q band.

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Zinc(II) Tetraphenylporphyrin on Ag(100) and Ag(111): Multilayer Desorption and Dehydrogenation

Cited by 38 publications

References 71 publications

On‐Surface Metalation and 2D Self‐Assembly of Pyrphyrin Molecules Into Metal‐Coordinated Networks on Cu(111)

On‐Surface Metalation and 2D Self‐Assembly of Pyrphyrin Molecules Into Metal‐Coordinated Networks on Cu(111)

The Orientation of Silver Surfaces Drives the Reactivity and the Selectivity in Homo‐Coupling Reactions

Electronic structure of tetra(4-aminophenyl)porphyrin studied by photoemission, UV–Vis spectroscopy and density functional theory

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