Ferrocenyl-Functionalized eta(5)-Thiophene Cr(CO)(3) Half-Sandwich Compounds

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

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The synthesis of eta(5)-Cr(CO)(3) complexed 2,5-Fc(2)- (3a), 3,4-Fc(2)- (3b), 2,3-Fc(2)- (3c) and 2-Fc-3,4,5-Me-3-thiophenes (3d) [Fc = Fe(eta(5)-C5H4)(eta(5)-C5H5)] is described. These half-sandwich compounds are accessible by the reaction of Cr(CO)(3)(MeCN)(3) with the appropriate substituted thiophenes. The compounds were analyzed by NMR spectroscopy, where a highfield shift for the ring-carbons and substituted hydrogen atoms of the thiophene core occurred. The 2,5- and 3,4-derivatives could be characterized structurally by single-crystal X-ray diffraction analysis, demonstrating that a low bending of the sulfur atom out of the thiophene plane of up to 9.95(17)degrees and an anti-arrangement of the ferrocenyl and Cr(CO)(3) fragments is characteristic. Electrochemical measurements showed that each ferrocenyl unit could be oxidized separately with higher redox separations for the ferrocenyls of Cr(CO)(3) complexes 3b (372 mV) and 3c (334 mV), than for the non complexed species 1b (244 mV) and 1c (283 mV). The potentials of the oxidation processes are shifted anodically by up to 144 mV, indicating an electron-withdrawing character of the Cr(CO)(3) unit. The irreversible Cr/Cr+ oxidations occurred at 545-895 mV. Within the electrochemical studies it could be shown that upon oxidation of the ferrocenyls the Cr(CO)(3) half-sandwich compounds rapidly decompose giving their non complexed thiophenes 1a-d. Solely for the Cr(CO)(3)-2,3,4,5-Me-4-thiophene 3d a reversible redox behavior was observed.

Original languageEnglish
Pages (from-to)4566-4572
Number of pages7
JournalEuropean Journal of Inorganic Chemistry
Issue number41
DOIs
Publication statusPublished - 8 Nov 2018
Externally publishedYes

Cite this

Speck, J. Matthaeus ; Korb, Marcus ; Hildebrandt, Alexander ; Lang, Heinrich. / Ferrocenyl-Functionalized eta(5)-Thiophene Cr(CO)(3) Half-Sandwich Compounds. In: European Journal of Inorganic Chemistry. 2018 ; No. 41. pp. 4566-4572.
@article{06cf3c0656ca428ab03eed2fe7a792fa,
title = "Ferrocenyl-Functionalized eta(5)-Thiophene Cr(CO)(3) Half-Sandwich Compounds",
abstract = "The synthesis of eta(5)-Cr(CO)(3) complexed 2,5-Fc(2)- (3a), 3,4-Fc(2)- (3b), 2,3-Fc(2)- (3c) and 2-Fc-3,4,5-Me-3-thiophenes (3d) [Fc = Fe(eta(5)-C5H4)(eta(5)-C5H5)] is described. These half-sandwich compounds are accessible by the reaction of Cr(CO)(3)(MeCN)(3) with the appropriate substituted thiophenes. The compounds were analyzed by NMR spectroscopy, where a highfield shift for the ring-carbons and substituted hydrogen atoms of the thiophene core occurred. The 2,5- and 3,4-derivatives could be characterized structurally by single-crystal X-ray diffraction analysis, demonstrating that a low bending of the sulfur atom out of the thiophene plane of up to 9.95(17)degrees and an anti-arrangement of the ferrocenyl and Cr(CO)(3) fragments is characteristic. Electrochemical measurements showed that each ferrocenyl unit could be oxidized separately with higher redox separations for the ferrocenyls of Cr(CO)(3) complexes 3b (372 mV) and 3c (334 mV), than for the non complexed species 1b (244 mV) and 1c (283 mV). The potentials of the oxidation processes are shifted anodically by up to 144 mV, indicating an electron-withdrawing character of the Cr(CO)(3) unit. The irreversible Cr/Cr+ oxidations occurred at 545-895 mV. Within the electrochemical studies it could be shown that upon oxidation of the ferrocenyls the Cr(CO)(3) half-sandwich compounds rapidly decompose giving their non complexed thiophenes 1a-d. Solely for the Cr(CO)(3)-2,3,4,5-Me-4-thiophene 3d a reversible redox behavior was observed.",
keywords = "Ferrocene, Heterocycles, Carbonyls, Electrochemistry, Single crystal structure, SOLID-STATE STRUCTURE, 5-MEMBERED HETEROCYCLES, ELECTRONIC INTERACTIONS, THIOPHENE DERIVATIVES, BIMETALLIC COMPLEXES, NONAQUEOUS SOLVENTS, DELTA-E-1/2 VALUES, ELECTROCHEMISTRY, LIGANDS, SYSTEMS",
author = "Speck, {J. Matthaeus} and Marcus Korb and Alexander Hildebrandt and Heinrich Lang",
year = "2018",
month = "11",
day = "8",
doi = "10.1002/ejic.201800749",
language = "English",
pages = "4566--4572",
journal = "European Journal of Inorganic Chemistry",
issn = "1099-0682",
publisher = "Wiley-VCH Verlag GmbH & Co. KGaA",
number = "41",

}

Ferrocenyl-Functionalized eta(5)-Thiophene Cr(CO)(3) Half-Sandwich Compounds. / Speck, J. Matthaeus; Korb, Marcus; Hildebrandt, Alexander; Lang, Heinrich.

In: European Journal of Inorganic Chemistry, No. 41, 08.11.2018, p. 4566-4572.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Ferrocenyl-Functionalized eta(5)-Thiophene Cr(CO)(3) Half-Sandwich Compounds

AU - Speck, J. Matthaeus

AU - Korb, Marcus

AU - Hildebrandt, Alexander

AU - Lang, Heinrich

PY - 2018/11/8

Y1 - 2018/11/8

N2 - The synthesis of eta(5)-Cr(CO)(3) complexed 2,5-Fc(2)- (3a), 3,4-Fc(2)- (3b), 2,3-Fc(2)- (3c) and 2-Fc-3,4,5-Me-3-thiophenes (3d) [Fc = Fe(eta(5)-C5H4)(eta(5)-C5H5)] is described. These half-sandwich compounds are accessible by the reaction of Cr(CO)(3)(MeCN)(3) with the appropriate substituted thiophenes. The compounds were analyzed by NMR spectroscopy, where a highfield shift for the ring-carbons and substituted hydrogen atoms of the thiophene core occurred. The 2,5- and 3,4-derivatives could be characterized structurally by single-crystal X-ray diffraction analysis, demonstrating that a low bending of the sulfur atom out of the thiophene plane of up to 9.95(17)degrees and an anti-arrangement of the ferrocenyl and Cr(CO)(3) fragments is characteristic. Electrochemical measurements showed that each ferrocenyl unit could be oxidized separately with higher redox separations for the ferrocenyls of Cr(CO)(3) complexes 3b (372 mV) and 3c (334 mV), than for the non complexed species 1b (244 mV) and 1c (283 mV). The potentials of the oxidation processes are shifted anodically by up to 144 mV, indicating an electron-withdrawing character of the Cr(CO)(3) unit. The irreversible Cr/Cr+ oxidations occurred at 545-895 mV. Within the electrochemical studies it could be shown that upon oxidation of the ferrocenyls the Cr(CO)(3) half-sandwich compounds rapidly decompose giving their non complexed thiophenes 1a-d. Solely for the Cr(CO)(3)-2,3,4,5-Me-4-thiophene 3d a reversible redox behavior was observed.

AB - The synthesis of eta(5)-Cr(CO)(3) complexed 2,5-Fc(2)- (3a), 3,4-Fc(2)- (3b), 2,3-Fc(2)- (3c) and 2-Fc-3,4,5-Me-3-thiophenes (3d) [Fc = Fe(eta(5)-C5H4)(eta(5)-C5H5)] is described. These half-sandwich compounds are accessible by the reaction of Cr(CO)(3)(MeCN)(3) with the appropriate substituted thiophenes. The compounds were analyzed by NMR spectroscopy, where a highfield shift for the ring-carbons and substituted hydrogen atoms of the thiophene core occurred. The 2,5- and 3,4-derivatives could be characterized structurally by single-crystal X-ray diffraction analysis, demonstrating that a low bending of the sulfur atom out of the thiophene plane of up to 9.95(17)degrees and an anti-arrangement of the ferrocenyl and Cr(CO)(3) fragments is characteristic. Electrochemical measurements showed that each ferrocenyl unit could be oxidized separately with higher redox separations for the ferrocenyls of Cr(CO)(3) complexes 3b (372 mV) and 3c (334 mV), than for the non complexed species 1b (244 mV) and 1c (283 mV). The potentials of the oxidation processes are shifted anodically by up to 144 mV, indicating an electron-withdrawing character of the Cr(CO)(3) unit. The irreversible Cr/Cr+ oxidations occurred at 545-895 mV. Within the electrochemical studies it could be shown that upon oxidation of the ferrocenyls the Cr(CO)(3) half-sandwich compounds rapidly decompose giving their non complexed thiophenes 1a-d. Solely for the Cr(CO)(3)-2,3,4,5-Me-4-thiophene 3d a reversible redox behavior was observed.

KW - Ferrocene

KW - Heterocycles

KW - Carbonyls

KW - Electrochemistry

KW - Single crystal structure

KW - SOLID-STATE STRUCTURE

KW - 5-MEMBERED HETEROCYCLES

KW - ELECTRONIC INTERACTIONS

KW - THIOPHENE DERIVATIVES

KW - BIMETALLIC COMPLEXES

KW - NONAQUEOUS SOLVENTS

KW - DELTA-E-1/2 VALUES

KW - ELECTROCHEMISTRY

KW - LIGANDS

KW - SYSTEMS

U2 - 10.1002/ejic.201800749

DO - 10.1002/ejic.201800749

M3 - Article

SP - 4566

EP - 4572

JO - European Journal of Inorganic Chemistry

JF - European Journal of Inorganic Chemistry

SN - 1099-0682

IS - 41

ER -