Manipulation of the electronic structure by reversible dehydrogenation of tetra(p-hydroxyphenyl)porphyrin molecules

Smykalla, Lars; Shukrynau, Pavel; Mende, Carola; Rüffer, Tobias; Lang, Heinrich; Hietschold, Michael

doi:10.1016/j.susc.2014.05.015

Cited by 24 publications

(44 citation statements)

References 43 publications

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“…Section 6.5) [528]. Besides these low-temperature STM manipulation experiments, tip-induced reversible detachment and re-attachment of both pyrrolic hydrogen atoms at room temperature have been reported for 2HTHPP on Au(1 1 1) [405].…”

Section: Manipulation Of Adsorbed Porphyrins and Phthalocyaninesmentioning

confidence: 68%

“…Comparison with the more reactive Ag(1 1 0) surface resulted in a higher adsorption energy and a smaller molecule-surface separation for the latter [404]. STM-induced removal of the two pyrrolic hydrogen atoms led to changes of the electronic structure, in particular a widening of the molecular HOMO-LUMO gap [405].…”

Section: Free-base Porphyrins and Phthalocyaninesmentioning

confidence: 98%

“…On Au (1 1 1), two different molecular arrangements were observed: A near-square structure with pair-wise hydrogen bonding between the OH groups of neighboring molecules and a relatively low packing density (0.35 molecules per nm 2 ), which enables rotation of the molecules relative to the lattice vectors, and a denser structure (0.42 molecules per nm 2 ) with an oblique unit cell (701). In the oblique structure, each four OH groups from neighboring molecules were reported to form hydrogen-bonded zig-zag chains [404]. The pyrrolic hydrogen atoms were reversibly detached by roomtemperature STM manipulation (cf.…”

Section: Tetraphenylporphyrins and Derivativesmentioning

confidence: 99%

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Surface chemistry of porphyrins and phthalocyanines

Gottfried

2015

Surface Science Reports

584

586

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Section: Manipulation Of Adsorbed Porphyrins and Phthalocyaninesmentioning

confidence: 68%

Section: Free-base Porphyrins and Phthalocyaninesmentioning

confidence: 98%

Section: Tetraphenylporphyrins and Derivativesmentioning

confidence: 99%

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Surface chemistry of porphyrins and phthalocyanines

Gottfried

2015

Surface Science Reports

584

586

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“…Firstly, metalation is known to be absent on Au(111) at room temperature [35] and proceeds even on the more reactive Cu(111) surface at temperatures exceeding 400 K [33]. Secondly, deprotonation [36] of the porphyrin cavity does not occur spontaneously at room temperature [37] and furthermore is not in accordance with our observation that the molecules change their appearance when being moved off and onto gold adatoms [30]. By taking many subsequent STM images of the same area, molecules can be studied in different environments (see Mielke_movie1 [26]).…”

mentioning

confidence: 99%

Observing single-atom diffusion at a molecule-metal interface

et al. 2016

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The dynamics at the interface between a close-packed porphyrin monolayer and Au(111) is investigated by time-dependent scanning tunneling microscopy, detecting the motion of single-interface adatoms in real space. Imaging sequences reveal predominant switching of the molecular appearance in adjacent molecules, pointing to a spatial correlation that is consistent with adatom diffusion from one molecule to the next. In some cases, the number of switching molecules is drastically increased, indicating collective switching events. In addition to the thermally induced motion of adatoms at the interface, also voltage pulses from the microscope tip can induce the process-revealing different yields in agreement with the model of adatom hopping. DOI: 10.1103/PhysRevB.94.035416 The interface between organic molecules and metal substrates plays a key role for many properties that are important, for instance, in catalytically driven reactions [1,2] and for charge transport [3]. The study of such systems gives detailed insight into fundamental processes that take place at an organic-inorganic interface. For an in-depth understanding, it is advantageous to use a scanning tunneling microscope (STM) for imaging because it provides information about the local environment of each individual molecule, which is important since the molecular properties might differ locallydue to defects, step edges, or different areas of a surface reconstruction [4,5]. For instance, individual C 60 molecules were found to change between dark and bright appearances in STM images, caused by the diffusion of surface [6] or bulk [7] vacancies, charge transfer between molecule and surface [8], or adsorption on small metal islands [9].Adatoms are known to diffuse on close-packed metal surfaces if the thermal energy is sufficient for their detachment from step edges [10]. When molecules are adsorbed on such a surface, the adatoms can interact with and even be trapped by molecules [11][12][13][14][15], leading to characteristic metallic nanostructures that reflect the molecular shape [16][17][18]. In addition to these self-organized structures, manipulation of single adatoms has been used to bring them in contact with molecules [19,20]. So far, real space studies of the molecule-surface interaction have been done mainly under static conditions [21,22] or focus on the lateral diffusion of molecules on surfaces [23][24][25]. Here, we report the dynamic behavior at the molecule-metal interface by observing the motion of individual gold adatoms underneath a molecular monolayer on Au(111) in time.As a molecular system we have chosen tetrabromophenylporphyrin [Br 4 TPP; Fig. 1(a) The appearance of our molecules strongly depends on the applied bias voltage: At −0.5 V all molecules appear at a similar height, while at around −1 V two dark and one bright molecular appearances can be found [ Fig. 1(b)]. The two dark molecules could be identified as two tautomers without a gold adatom, while bright molecules have a single gold adatom underneath, causing the shift i...

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“…For example, (metallo)porphyrins were synthesized and deposited by OMBD for different kinds of physical thin-film studies [6–9]. In one of these contributions thin films of CuTPP(OMe) 4 (Fig.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, spectroscopic characterization and thermogravimetric analysis of two series of substituted (metallo)tetraphenylporphyrins

Al-Shewiki¹,

Mende²,

Buschbeck³

et al. 2017

Beilstein J. Nanotechnol.

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Subsequent treatment of H2TPP(CO2H)4 (tetra(p-carboxylic acid phenyl)porphyrin, 1) with an excess of oxalyl chloride and HNR2 afforded H2TPP(C(O)NR2)4 (R = Me, 2; iPr, 3) with yields exceeding 80%. The porphyrins 2 and 3 could be converted to the corresponding metalloporphyrins MTPP(C(O)NR2)4 (R = Me/iPr for M = Zn (2a, 3a); Cu (2b, 3b); Ni (2c, 3c); Co (2d, 3d)) by the addition of 3 equiv of anhydrous MCl2 (M = Zn, Cu, Ni, Co) to dimethylformamide solutions of 2 and 3 at elevated temperatures. Metalloporphyrins 2a–d and 3a–d were obtained in yields exceeding 60% and have been, as well as 2 and 3, characterized by elemental analysis, electrospray ionization mass spectrometry (ESIMS) and IR and UV–vis spectroscopy. Porphyrins 2, 2a–d and 3, 3a–d are not suitable for organic molecular beam deposition (OMBD), which is attributed to their comparatively low thermal stability as determined by thermogravimetric analysis (TG) of selected representatives.

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Manipulation of the electronic structure by reversible dehydrogenation of tetra(p-hydroxyphenyl)porphyrin molecules

Cited by 24 publications

References 43 publications

Surface chemistry of porphyrins and phthalocyanines

Surface chemistry of porphyrins and phthalocyanines

Observing single-atom diffusion at a molecule-metal interface

Synthesis, spectroscopic characterization and thermogravimetric analysis of two series of substituted (metallo)tetraphenylporphyrins

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