Synthesis and electron transfer properties of metal complex oligomer wires with an inherent potential gradient on gold electrode

Yoshihiko Nishimori; Hiroaki Maeda; Shunsuke Katagiri; Junya Sendo; Mariko Miyachi; Ryota Sakamoto; Yoshinori Yamanoi; Hiroshi Nishihara

doi:10.1002/masy.201200016

Synthesis and electron transfer properties of metal complex oligomer wires with an inherent potential gradient on gold electrode

Yoshihiko Nishimori, Hiroaki Maeda, Shunsuke Katagiri, Junya Sendo, Mariko Miyachi, Ryota Sakamoto, Yoshinori Yamanoi, Hiroshi Nishihara

Research output: Contribution to journal › Article › peer-review

14 Citations (Scopus)

Abstract

π-Conjugated bis(terpyridine)metal (M(tpy) ₂) oligomer wires were prepared by surface coordination programming such that they displayed an inherent potential gradient along the wire through the chain of metals and bridging ligands. The electron transfer properties of these wires were examined. Heterometal complex wires prepared in the sequence Au(111)-Co(tpy) ₂-Fe(tpy) ₂-ferrocene (Fc); that is, Au-[A _azo-1CoL _H-1FeT _Fc] ((A _azo) ₂ = bis((4-(4′-2,2′;6′,2″-terpyridyl) phenylazo)phenyl)disulfide, L _H = bis(terpyridyl)-p-phenylene), displayed a rate constant, k _et, for electron transfer at the terminal Fc moiety that was twice that obtained from wires prepared in the sequence electrode-Fe(tpy) ₂-Co(tpy) ₂-Fc, Au-[A _azo- 1FeL _H-1CoT _Fc]. This suggested that the oxidation reaction at the terminal Fc moiety was mediated by electron transfer via Co(tpy) ₂ more efficiently than via Fe(tpy) ₂. Metal complex wires with an inherent potential gradient based on the heteroligand combination were synthesized using bis(4-(4′-2,2′;6′,2″-terpyridyl) phenyl)disulfide, (A _H) ₂, or bis(4-(4′-5,5″- difluoro-2,2′;6′,2″-terpyridyl)phenyl)disulfide, (A _F) ₂, as anchoring ligands and bis(terpyridyl)-p-phenylene, L _H, or bis(terpyridyl)-tetrafluoro-p-phenylene, L _F, as bridging ligands. Potential step chronoamperometry (PSCA) measurements of the redox reaction of Au-[A _H-1FeL ₁-2FeL _F] and Au-[A _F-1FeL _F-2FeL _H] revealed only small differences in the current-time curves, indicating that the electron self-exchange between the Fe(tpy) ₂ units in a wire was faster than electron transfer between an electrode surface and the adjacent Fe(tpy) ₂ units. Fast electron self-exchange suppressed the expected rectification behavior of the wire, despite the presence of a potential staircase within the wire.

Original language	English
Pages (from-to)	276-285
Number of pages	10
Journal	Macromolecular Symposia
Volume	317-318
Issue number	1
DOIs	https://doi.org/10.1002/masy.201200016
Publication status	Published - 2012 Aug
Externally published	Yes

Keywords

coordination programming
cyclic voltammogram
electrochemistry
potential gradient
terpyridine complex

ASJC Scopus subject areas

Condensed Matter Physics
Organic Chemistry
Polymers and Plastics
Materials Chemistry

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10.1002/masy.201200016

Cite this

@article{46887b84200a400ea38894dca820be9c,

title = "Synthesis and electron transfer properties of metal complex oligomer wires with an inherent potential gradient on gold electrode",

abstract = "π-Conjugated bis(terpyridine)metal (M(tpy) 2) oligomer wires were prepared by surface coordination programming such that they displayed an inherent potential gradient along the wire through the chain of metals and bridging ligands. The electron transfer properties of these wires were examined. Heterometal complex wires prepared in the sequence Au(111)-Co(tpy) 2-Fe(tpy) 2-ferrocene (Fc); that is, Au-[A azo-1CoL H-1FeT Fc] ((A azo) 2 = bis((4-(4′-2,2′;6′,2″-terpyridyl) phenylazo)phenyl)disulfide, L H = bis(terpyridyl)-p-phenylene), displayed a rate constant, k et, for electron transfer at the terminal Fc moiety that was twice that obtained from wires prepared in the sequence electrode-Fe(tpy) 2-Co(tpy) 2-Fc, Au-[A azo- 1FeL H-1CoT Fc]. This suggested that the oxidation reaction at the terminal Fc moiety was mediated by electron transfer via Co(tpy) 2 more efficiently than via Fe(tpy) 2. Metal complex wires with an inherent potential gradient based on the heteroligand combination were synthesized using bis(4-(4′-2,2′;6′,2″-terpyridyl) phenyl)disulfide, (A H) 2, or bis(4-(4′-5,5″- difluoro-2,2′;6′,2″-terpyridyl)phenyl)disulfide, (A F) 2, as anchoring ligands and bis(terpyridyl)-p-phenylene, L H, or bis(terpyridyl)-tetrafluoro-p-phenylene, L F, as bridging ligands. Potential step chronoamperometry (PSCA) measurements of the redox reaction of Au-[A H-1FeL 1-2FeL F] and Au-[A F-1FeL F-2FeL H] revealed only small differences in the current-time curves, indicating that the electron self-exchange between the Fe(tpy) 2 units in a wire was faster than electron transfer between an electrode surface and the adjacent Fe(tpy) 2 units. Fast electron self-exchange suppressed the expected rectification behavior of the wire, despite the presence of a potential staircase within the wire.",

keywords = "coordination programming, cyclic voltammogram, electrochemistry, potential gradient, terpyridine complex",

author = "Yoshihiko Nishimori and Hiroaki Maeda and Shunsuke Katagiri and Junya Sendo and Mariko Miyachi and Ryota Sakamoto and Yoshinori Yamanoi and Hiroshi Nishihara",

year = "2012",

month = aug,

doi = "10.1002/masy.201200016",

language = "English",

volume = "317-318",

pages = "276--285",

journal = "Macromolecular Symposia",

issn = "1022-1360",

publisher = "Wiley-VCH Verlag",

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TY - JOUR

T1 - Synthesis and electron transfer properties of metal complex oligomer wires with an inherent potential gradient on gold electrode

AU - Nishimori, Yoshihiko

AU - Maeda, Hiroaki

AU - Katagiri, Shunsuke

AU - Sendo, Junya

AU - Miyachi, Mariko

AU - Sakamoto, Ryota

AU - Yamanoi, Yoshinori

AU - Nishihara, Hiroshi

PY - 2012/8

Y1 - 2012/8

N2 - π-Conjugated bis(terpyridine)metal (M(tpy) 2) oligomer wires were prepared by surface coordination programming such that they displayed an inherent potential gradient along the wire through the chain of metals and bridging ligands. The electron transfer properties of these wires were examined. Heterometal complex wires prepared in the sequence Au(111)-Co(tpy) 2-Fe(tpy) 2-ferrocene (Fc); that is, Au-[A azo-1CoL H-1FeT Fc] ((A azo) 2 = bis((4-(4′-2,2′;6′,2″-terpyridyl) phenylazo)phenyl)disulfide, L H = bis(terpyridyl)-p-phenylene), displayed a rate constant, k et, for electron transfer at the terminal Fc moiety that was twice that obtained from wires prepared in the sequence electrode-Fe(tpy) 2-Co(tpy) 2-Fc, Au-[A azo- 1FeL H-1CoT Fc]. This suggested that the oxidation reaction at the terminal Fc moiety was mediated by electron transfer via Co(tpy) 2 more efficiently than via Fe(tpy) 2. Metal complex wires with an inherent potential gradient based on the heteroligand combination were synthesized using bis(4-(4′-2,2′;6′,2″-terpyridyl) phenyl)disulfide, (A H) 2, or bis(4-(4′-5,5″- difluoro-2,2′;6′,2″-terpyridyl)phenyl)disulfide, (A F) 2, as anchoring ligands and bis(terpyridyl)-p-phenylene, L H, or bis(terpyridyl)-tetrafluoro-p-phenylene, L F, as bridging ligands. Potential step chronoamperometry (PSCA) measurements of the redox reaction of Au-[A H-1FeL 1-2FeL F] and Au-[A F-1FeL F-2FeL H] revealed only small differences in the current-time curves, indicating that the electron self-exchange between the Fe(tpy) 2 units in a wire was faster than electron transfer between an electrode surface and the adjacent Fe(tpy) 2 units. Fast electron self-exchange suppressed the expected rectification behavior of the wire, despite the presence of a potential staircase within the wire.

AB - π-Conjugated bis(terpyridine)metal (M(tpy) 2) oligomer wires were prepared by surface coordination programming such that they displayed an inherent potential gradient along the wire through the chain of metals and bridging ligands. The electron transfer properties of these wires were examined. Heterometal complex wires prepared in the sequence Au(111)-Co(tpy) 2-Fe(tpy) 2-ferrocene (Fc); that is, Au-[A azo-1CoL H-1FeT Fc] ((A azo) 2 = bis((4-(4′-2,2′;6′,2″-terpyridyl) phenylazo)phenyl)disulfide, L H = bis(terpyridyl)-p-phenylene), displayed a rate constant, k et, for electron transfer at the terminal Fc moiety that was twice that obtained from wires prepared in the sequence electrode-Fe(tpy) 2-Co(tpy) 2-Fc, Au-[A azo- 1FeL H-1CoT Fc]. This suggested that the oxidation reaction at the terminal Fc moiety was mediated by electron transfer via Co(tpy) 2 more efficiently than via Fe(tpy) 2. Metal complex wires with an inherent potential gradient based on the heteroligand combination were synthesized using bis(4-(4′-2,2′;6′,2″-terpyridyl) phenyl)disulfide, (A H) 2, or bis(4-(4′-5,5″- difluoro-2,2′;6′,2″-terpyridyl)phenyl)disulfide, (A F) 2, as anchoring ligands and bis(terpyridyl)-p-phenylene, L H, or bis(terpyridyl)-tetrafluoro-p-phenylene, L F, as bridging ligands. Potential step chronoamperometry (PSCA) measurements of the redox reaction of Au-[A H-1FeL 1-2FeL F] and Au-[A F-1FeL F-2FeL H] revealed only small differences in the current-time curves, indicating that the electron self-exchange between the Fe(tpy) 2 units in a wire was faster than electron transfer between an electrode surface and the adjacent Fe(tpy) 2 units. Fast electron self-exchange suppressed the expected rectification behavior of the wire, despite the presence of a potential staircase within the wire.

KW - coordination programming

KW - cyclic voltammogram

KW - electrochemistry

KW - potential gradient

KW - terpyridine complex

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Synthesis and electron transfer properties of metal complex oligomer wires with an inherent potential gradient on gold electrode

Abstract

Keywords

ASJC Scopus subject areas

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