Self-Organized Porphyrin Array on Iodine-Modified Au(111) in Electrolyte Solutions: In Situ Scanning Tunneling Microscopy Study

Kunitake, Masashi; Batina, Nikola; Itaya, Kingo

doi:10.1021/la00007a002

Cited by 201 publications

(202 citation statements)

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“…22 The Au-I surface was exposed to the mixed solution of PAHs, but the STM images for this modified surface did not reveal organized domains that could be assigned to PAHs. Pyridinethiol (PyS) also has a pyridine moiety pointing to solution when adsorbed on Au(111) as HPYT.…”

Section: Scanning Tunneling Microscopymentioning

confidence: 95%

Polycyclic aromatic hydrocarbons from asphalt binder: extraction and characterization

Pinheiro¹,

Fernandes²,

Cavalcante³

et al. 2009

J. Braz. Chem. Soc.

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Section: Scanning Tunneling Microscopymentioning

confidence: 95%

Polycyclic aromatic hydrocarbons from asphalt binder: extraction and characterization

Pinheiro¹,

Fernandes²,

Cavalcante³

et al. 2009

J. Braz. Chem. Soc.

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“…Itaya et al demonstrated that the ordering of porphyrin molecules on metal surfaces can be promoted by a passivating layer of iodine, which reduces the adsorbate-substrate interaction and facilitates surface diffusion. [10][11][12] The effect of surface charge was demonstrated by Hipps et al with the coadsorption of F16CoPc (Pc ) phthalocyanines) and NiTPP in an ultra high vacuum environment. 4 The electron-withdrawing F16CoPc alone cannot form ordered adlayers due to strong electrostatic interaction with the surface.…”

Section: Introductionmentioning

confidence: 97%

Adsorption and Electrochemical Activity: An In Situ Electrochemical Scanning Tunneling Microscopy Study of Electrode Reactions and Potential-Induced Adsorption of Porphyrins

Borguet

2006

J. Phys. Chem. B

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The effect of adsorption on molecular properties and reactivity is a central topic in interfacial physical chemistry. At electrochemical interfaces, adsorbed molecules may lose their electrochemical activity. The absence of in situ probes has hindered our understanding of this phenomenon and electrode reactions in general. In this work, classical electrochemistry and electrochemical scanning tunneling microscopy (EC-STM) were combined to provide molecular level insight into electrochemical reactions and the molecular adsorption state at the electrolyte-electrode interface. The metal-free porphyrin 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (TPyP) adsorbed on Au(111) in 0.1 M H 2 SO 4 solution was chosen as a model system. TPyP is found to irreversibly adsorb on Au(111) over a wide range of potentials, from -0.25 to 0.6 V SCE . The adsorption state of TPyP has a dramatic effect on its electrochemistry. Preadsorbed, oxidized TPyP displays no well-defined cathodic peaks in cyclic voltammograms in sharp contrast to solution-phase TPyP. Our present work provides direct, molecular level evidence of the electrochemically "invisible" species. Electrochemical activity of absorbed species is recovered by allowing the oxidized molecule sufficient time (tens of minutes) to reduce. The redox state of adsorbed TPyP also affects the nature of the adsorption. Oxidized species can apparently only form monolayers. However, multilayers, stable enough to be imaged by STM, can form when the adsorbed TPyP is in the reduced state. This suggests that by controlling the electrochemistry one can either promote or suppress the formation of multilayers.

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“…In situ STM offers, on the other hand, new electrochemical spectroscopic probes in addition to current-bias voltage relations, particularly the relation between the tunnel current and the overvoltage of both the tip and substrate electrodes relative to a common reference electrode. High-resolution mapping of adsorption patterns at the solid͞aqueous solution interface by in situ STM has covered, for example, carbon monoxide (35), alkane thiols (36,37), DNA bases (38)(39)(40)(41)(42), and other intermediate-size molecules such as porphyrins (43,44) and tetramethylthiourea (45). In situ STM͞AFM also has been brought to a level at which solid͞aqueous solution structure and reactivity are coming within reach.…”

mentioning

confidence: 99%

An approach to long-range electron transfer mechanisms in metalloproteins: In situ scanning tunneling microscopy with submolecular resolution

Friis

Andersen

Kharkats

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

130

106

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In situ scanning tunneling microscopy (STM) of redox molecules, in aqueous solution, shows interesting analogies and differences compared with interfacial electrochemical electron transfer ( Molecular long-range electron transfer (ET) in solid phases or liquid solution, in which the ET distance exceeds the structural extension of the donor and acceptor, has been in focus over the last decade and a half (1-5). Progress has rested on synthetic donor-acceptor molecules (1-3), metalloproteins (2, 4, 6, 7), and on new electrochemical systems in which electrons are brought to tunnel across well characterized, self-assembled films (8, 9). These achievements have prompted new theoretical efforts with notions such as directional tunneling along chemical bond networks (10), fluctuating tunnel barriers (11, 12), coherent and resonance ET (13), and self-consistent electronic-vibrational interaction (11).In a parallel development, scanning tunneling and atomic force microscopy (STM and AFM, respectively) have opened exciting new perspectives for mapping molecular adsorbate patterns (14, 15). The primary basis for adsorption patterns in vacuum or air is imaging of small and intermediate-size adsorbate molecules with molecular and submolecular resolution (14-17), combined with theoretical frames for tunneling through adsorbate molecules based on different methodologies (17-21). There are also reported experimental approaches to functional mapping of intermediate-size molecules, most prominently in the form of correlations between the tunnel current and the bias voltage. Target adsorbates for ex situ STM imaging have been, for example, benzene (22, 23), methylazulenes (17, 24), C 60 (25), alkyl and aryl thiolates (17,21,(26)(27)(28), and transition metal phthalocyanins (29) on highly oriented pyrolytic graphite or crystalline surfaces of electronically ''soft'' metals compatible with the adsorbates. STM imaging at the solid͞air interface to molecular and occasionally submolecular resolution also has been extended to biological macromolecules including DNA (30) and a number of redox and nonredox proteins (for an overview, see ref. 31). Functional properties addressed particularly have been the electrical potential distribution and conductivity patterns of the tunnel gap (21, 27-29), resonance tunneling via suitable highest occupied molecular orbitals, lowest unoccupied molecular orbitals, or (transition metal) redox levels (17-21), and the notion of orbital-specific mediation of the tunnel current (29).Combination of STM with concepts of long-range ET in chemical and, particularly, metalloprotein systems must, however, give explicit attention to the fact that the natural medium for most chemical and biological reactivity is aqueous solution. Extension of STM͞AFM to aqueous solution (in situ STM͞ AFM) is established (32, 33) but has raised issues related to adsorbate immobilization, ultrapure solutions, tip coating, independent tip and substrate potential control (32-34), and the fundamental STM and AFM phenomena. In situ...

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Self-Organized Porphyrin Array on Iodine-Modified Au(111) in Electrolyte Solutions: In Situ Scanning Tunneling Microscopy Study

Cited by 201 publications

References 0 publications

Polycyclic aromatic hydrocarbons from asphalt binder: extraction and characterization

Polycyclic aromatic hydrocarbons from asphalt binder: extraction and characterization

Adsorption and Electrochemical Activity: An In Situ Electrochemical Scanning Tunneling Microscopy Study of Electrode Reactions and Potential-Induced Adsorption of Porphyrins

An approach to long-range electron transfer mechanisms in metalloproteins: In situ scanning tunneling microscopy with submolecular resolution

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