Synthesis and Electrochemical Investigations of [Ru(eta(5)-Ferrocenyl-Thiophene)(eta(5)-C5R5)](+) Sandwich Compounds

J. Matthaeus Speck, Marcus Korb, Alexander Hildebrandt, Heinrich Lang

Research output: Contribution to journalArticle

Abstract

The synthesis of [Ru(eta(5)-2-Fc-3-R-3-4-R-2-5-R-1-A (c) C4S)(eta(5)-C5R5)](+)[PF6](-) (R = H, Me; R-1-R-3 = H; R-1 = Me, R-2 = R-3 = H; R-1-R-3 = Me; R-1 = Fc, R-2 = R-3 = OCH2CH2O; Fc = Fe(eta(5)-C5H4)(eta(5)-C5H5)) is reported with the aim of a better understanding of the influence of pi-thiophene-bonded transition metal units on the thermodynamic stabilities and charge transfer interactions of the resulting compounds and their oxidized intermediates. Within the electrochemical studies, reversible one-electron Fe-based redox events were found for the mono-Fc Ru species, whereby the Fc/Fc(+) redox potential increases as the degree of methylation of the thiophene and the Ru-cyclopentadienyl moiety decreases. For [Ru(eta(5)-2,5-Fc(2)-A (c) C4H2S)(eta(5)-C5R5)](+)[PF6](-) a hindered 2(nd) Fc-based electrode reaction was observed under "weak-coordinating" conditions. Two separated Fc/Fc(+) redox events were detected by the use of stronger solvating solvents or (smaller) anions. With regard to the non complexed 2,5-Fc(2) thiophenes, the thermodynamic stabilities of the appropriate mixed-valent species decrease, when the thiophene is eta(5)-coordinated to [Ru(eta(5)-C5R5)](+). Contrary to the redox potential, the substitution of the [Ru(eta(5)-C5R5)](+) moiety does not have a major impact on the thermodynamic stabilities of the mixed-valent species. The related decrease of electronic coupling between the Fc unit(s) via the thiophene in the corresponding oxidized states, could be verified during UV/Vis/NIR spectroelectrochemical studies.

Original languageEnglish
Pages (from-to)2419-2429
Number of pages11
JournalEuropean Journal of Inorganic Chemistry
Issue number19
DOIs
Publication statusPublished - 26 May 2019

Cite this

@article{ea6068bc2bb14730a75eaa56f816cc0d,
title = "Synthesis and Electrochemical Investigations of [Ru(eta(5)-Ferrocenyl-Thiophene)(eta(5)-C5R5)](+) Sandwich Compounds",
abstract = "The synthesis of [Ru(eta(5)-2-Fc-3-R-3-4-R-2-5-R-1-A (c) C4S)(eta(5)-C5R5)](+)[PF6](-) (R = H, Me; R-1-R-3 = H; R-1 = Me, R-2 = R-3 = H; R-1-R-3 = Me; R-1 = Fc, R-2 = R-3 = OCH2CH2O; Fc = Fe(eta(5)-C5H4)(eta(5)-C5H5)) is reported with the aim of a better understanding of the influence of pi-thiophene-bonded transition metal units on the thermodynamic stabilities and charge transfer interactions of the resulting compounds and their oxidized intermediates. Within the electrochemical studies, reversible one-electron Fe-based redox events were found for the mono-Fc Ru species, whereby the Fc/Fc(+) redox potential increases as the degree of methylation of the thiophene and the Ru-cyclopentadienyl moiety decreases. For [Ru(eta(5)-2,5-Fc(2)-A (c) C4H2S)(eta(5)-C5R5)](+)[PF6](-) a hindered 2(nd) Fc-based electrode reaction was observed under {"}weak-coordinating{"} conditions. Two separated Fc/Fc(+) redox events were detected by the use of stronger solvating solvents or (smaller) anions. With regard to the non complexed 2,5-Fc(2) thiophenes, the thermodynamic stabilities of the appropriate mixed-valent species decrease, when the thiophene is eta(5)-coordinated to [Ru(eta(5)-C5R5)](+). Contrary to the redox potential, the substitution of the [Ru(eta(5)-C5R5)](+) moiety does not have a major impact on the thermodynamic stabilities of the mixed-valent species. The related decrease of electronic coupling between the Fc unit(s) via the thiophene in the corresponding oxidized states, could be verified during UV/Vis/NIR spectroelectrochemical studies.",
keywords = "Sandwich complexes, Cyclopentadienyl ligands, S ligands, Ruthenocene, Structure elucidation, Electrochemistry, MIXED-VALENCE COMPOUNDS, SOLID-STATE STRUCTURE, CHARGE-TRANSFER, ELECTRONIC-STRUCTURE, CYCLOMETALATED RUTHENIUM, ORGANOMETALLIC COMPLEXES, DELTA-E-1/2 VALUES, CRYSTAL-STRUCTURES, DELOCALIZATION, SUBSTITUENT",
author = "Speck, {J. Matthaeus} and Marcus Korb and Alexander Hildebrandt and Heinrich Lang",
year = "2019",
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doi = "10.1002/ejic.201900121",
language = "English",
pages = "2419--2429",
journal = "European Journal of Inorganic Chemistry",
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publisher = "Wiley-VCH Verlag GmbH & Co. KGaA",
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Synthesis and Electrochemical Investigations of [Ru(eta(5)-Ferrocenyl-Thiophene)(eta(5)-C5R5)](+) Sandwich Compounds. / Speck, J. Matthaeus; Korb, Marcus; Hildebrandt, Alexander; Lang, Heinrich.

In: European Journal of Inorganic Chemistry, No. 19, 26.05.2019, p. 2419-2429.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Synthesis and Electrochemical Investigations of [Ru(eta(5)-Ferrocenyl-Thiophene)(eta(5)-C5R5)](+) Sandwich Compounds

AU - Speck, J. Matthaeus

AU - Korb, Marcus

AU - Hildebrandt, Alexander

AU - Lang, Heinrich

PY - 2019/5/26

Y1 - 2019/5/26

N2 - The synthesis of [Ru(eta(5)-2-Fc-3-R-3-4-R-2-5-R-1-A (c) C4S)(eta(5)-C5R5)](+)[PF6](-) (R = H, Me; R-1-R-3 = H; R-1 = Me, R-2 = R-3 = H; R-1-R-3 = Me; R-1 = Fc, R-2 = R-3 = OCH2CH2O; Fc = Fe(eta(5)-C5H4)(eta(5)-C5H5)) is reported with the aim of a better understanding of the influence of pi-thiophene-bonded transition metal units on the thermodynamic stabilities and charge transfer interactions of the resulting compounds and their oxidized intermediates. Within the electrochemical studies, reversible one-electron Fe-based redox events were found for the mono-Fc Ru species, whereby the Fc/Fc(+) redox potential increases as the degree of methylation of the thiophene and the Ru-cyclopentadienyl moiety decreases. For [Ru(eta(5)-2,5-Fc(2)-A (c) C4H2S)(eta(5)-C5R5)](+)[PF6](-) a hindered 2(nd) Fc-based electrode reaction was observed under "weak-coordinating" conditions. Two separated Fc/Fc(+) redox events were detected by the use of stronger solvating solvents or (smaller) anions. With regard to the non complexed 2,5-Fc(2) thiophenes, the thermodynamic stabilities of the appropriate mixed-valent species decrease, when the thiophene is eta(5)-coordinated to [Ru(eta(5)-C5R5)](+). Contrary to the redox potential, the substitution of the [Ru(eta(5)-C5R5)](+) moiety does not have a major impact on the thermodynamic stabilities of the mixed-valent species. The related decrease of electronic coupling between the Fc unit(s) via the thiophene in the corresponding oxidized states, could be verified during UV/Vis/NIR spectroelectrochemical studies.

AB - The synthesis of [Ru(eta(5)-2-Fc-3-R-3-4-R-2-5-R-1-A (c) C4S)(eta(5)-C5R5)](+)[PF6](-) (R = H, Me; R-1-R-3 = H; R-1 = Me, R-2 = R-3 = H; R-1-R-3 = Me; R-1 = Fc, R-2 = R-3 = OCH2CH2O; Fc = Fe(eta(5)-C5H4)(eta(5)-C5H5)) is reported with the aim of a better understanding of the influence of pi-thiophene-bonded transition metal units on the thermodynamic stabilities and charge transfer interactions of the resulting compounds and their oxidized intermediates. Within the electrochemical studies, reversible one-electron Fe-based redox events were found for the mono-Fc Ru species, whereby the Fc/Fc(+) redox potential increases as the degree of methylation of the thiophene and the Ru-cyclopentadienyl moiety decreases. For [Ru(eta(5)-2,5-Fc(2)-A (c) C4H2S)(eta(5)-C5R5)](+)[PF6](-) a hindered 2(nd) Fc-based electrode reaction was observed under "weak-coordinating" conditions. Two separated Fc/Fc(+) redox events were detected by the use of stronger solvating solvents or (smaller) anions. With regard to the non complexed 2,5-Fc(2) thiophenes, the thermodynamic stabilities of the appropriate mixed-valent species decrease, when the thiophene is eta(5)-coordinated to [Ru(eta(5)-C5R5)](+). Contrary to the redox potential, the substitution of the [Ru(eta(5)-C5R5)](+) moiety does not have a major impact on the thermodynamic stabilities of the mixed-valent species. The related decrease of electronic coupling between the Fc unit(s) via the thiophene in the corresponding oxidized states, could be verified during UV/Vis/NIR spectroelectrochemical studies.

KW - Sandwich complexes

KW - Cyclopentadienyl ligands

KW - S ligands

KW - Ruthenocene

KW - Structure elucidation

KW - Electrochemistry

KW - MIXED-VALENCE COMPOUNDS

KW - SOLID-STATE STRUCTURE

KW - CHARGE-TRANSFER

KW - ELECTRONIC-STRUCTURE

KW - CYCLOMETALATED RUTHENIUM

KW - ORGANOMETALLIC COMPLEXES

KW - DELTA-E-1/2 VALUES

KW - CRYSTAL-STRUCTURES

KW - DELOCALIZATION

KW - SUBSTITUENT

U2 - 10.1002/ejic.201900121

DO - 10.1002/ejic.201900121

M3 - Article

SP - 2419

EP - 2429

JO - European Journal of Inorganic Chemistry

JF - European Journal of Inorganic Chemistry

SN - 1099-0682

IS - 19

ER -