(Spectro)electrochemical investigations on (ferrocenyl)thiophenes modified by tungsten Fischer carbenes

Belinda van der Westhuizen, J. Matthaeus Speck, Marcus Korb, Daniela I. Bezuidenhout, Heinrich Lang

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

A series of thiophene tungsten Fischer carbene complexes of type [(CO)(5)W=C(OMe)R] (1, R = 2 Th; 4, R = fcthFc) and [(CO)(5)W=C(OMe)-R'-(OMe)C=W(CO)(5)] (2, R' = th; 5, R' = fcthfc) was synthesized for investigating low energy charge transfer interactions between the carbene substituents and the transition metal carbonyl fragment incorporating the thiophene heterocyclic system (Th = Thienyl; th = 2,5-thiendiyl; Fc = ferrocenyl; fc = 1,1'-ferrocenediyl). Electrochemical investigations were carried out on these complexes to get a closer insight into the electronic properties of 1, 2, 4 and 5. Typical electrode reactions could be found for the carbene reductions itself and for the tungsten carbonyl oxidation processes in all metal carbene complexes. However, for the thiophene complex 2 two well-separated one-electron reduction events were observed, suggesting an interaction of the Fischer carbene moieties in 2(-), over the thiophene bridge. Reversible one-electron redox events for the ferrocenyl moieties in complexes 4 and 5 were also observed. During the UV Vis NIR spectroelectrochemical investigations typical low energy absorptions for the mixed-valent alpha,alpha'-diferrocenyl thiophene increment were found for these two complexes, as well as high energy NIR absorptions, which were attributed to metal metal charge transfer transition between the tungsten carbonyl increment and the ferrocenyl units (complexes 4 and 5). Further infrared spectroelectrochemical studies reveal that the electronic interactions between the tungsten carbene and the ferrocenyl electrophores in the corresponding cationic species (4(+), 4(2+), 5(+), 5(2+)) can be described with weakly coupled class II systems according to Robin and Day. (c) 2014 Elsevier BY. All rights reserved.

Original languageEnglish
Pages (from-to)18-26
Number of pages9
JournalJournal of Organometallic Chemistry
Volume772
DOIs
Publication statusPublished - 1 Dec 2014
Externally publishedYes

Cite this

van der Westhuizen, Belinda ; Speck, J. Matthaeus ; Korb, Marcus ; Bezuidenhout, Daniela I. ; Lang, Heinrich. / (Spectro)electrochemical investigations on (ferrocenyl)thiophenes modified by tungsten Fischer carbenes. In: Journal of Organometallic Chemistry. 2014 ; Vol. 772. pp. 18-26.
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abstract = "A series of thiophene tungsten Fischer carbene complexes of type [(CO)(5)W=C(OMe)R] (1, R = 2 Th; 4, R = fcthFc) and [(CO)(5)W=C(OMe)-R'-(OMe)C=W(CO)(5)] (2, R' = th; 5, R' = fcthfc) was synthesized for investigating low energy charge transfer interactions between the carbene substituents and the transition metal carbonyl fragment incorporating the thiophene heterocyclic system (Th = Thienyl; th = 2,5-thiendiyl; Fc = ferrocenyl; fc = 1,1'-ferrocenediyl). Electrochemical investigations were carried out on these complexes to get a closer insight into the electronic properties of 1, 2, 4 and 5. Typical electrode reactions could be found for the carbene reductions itself and for the tungsten carbonyl oxidation processes in all metal carbene complexes. However, for the thiophene complex 2 two well-separated one-electron reduction events were observed, suggesting an interaction of the Fischer carbene moieties in 2(-), over the thiophene bridge. Reversible one-electron redox events for the ferrocenyl moieties in complexes 4 and 5 were also observed. During the UV Vis NIR spectroelectrochemical investigations typical low energy absorptions for the mixed-valent alpha,alpha'-diferrocenyl thiophene increment were found for these two complexes, as well as high energy NIR absorptions, which were attributed to metal metal charge transfer transition between the tungsten carbonyl increment and the ferrocenyl units (complexes 4 and 5). Further infrared spectroelectrochemical studies reveal that the electronic interactions between the tungsten carbene and the ferrocenyl electrophores in the corresponding cationic species (4(+), 4(2+), 5(+), 5(2+)) can be described with weakly coupled class II systems according to Robin and Day. (c) 2014 Elsevier BY. All rights reserved.",
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(Spectro)electrochemical investigations on (ferrocenyl)thiophenes modified by tungsten Fischer carbenes. / van der Westhuizen, Belinda; Speck, J. Matthaeus; Korb, Marcus; Bezuidenhout, Daniela I.; Lang, Heinrich.

In: Journal of Organometallic Chemistry, Vol. 772, 01.12.2014, p. 18-26.

Research output: Contribution to journalArticle

TY - JOUR

T1 - (Spectro)electrochemical investigations on (ferrocenyl)thiophenes modified by tungsten Fischer carbenes

AU - van der Westhuizen, Belinda

AU - Speck, J. Matthaeus

AU - Korb, Marcus

AU - Bezuidenhout, Daniela I.

AU - Lang, Heinrich

PY - 2014/12/1

Y1 - 2014/12/1

N2 - A series of thiophene tungsten Fischer carbene complexes of type [(CO)(5)W=C(OMe)R] (1, R = 2 Th; 4, R = fcthFc) and [(CO)(5)W=C(OMe)-R'-(OMe)C=W(CO)(5)] (2, R' = th; 5, R' = fcthfc) was synthesized for investigating low energy charge transfer interactions between the carbene substituents and the transition metal carbonyl fragment incorporating the thiophene heterocyclic system (Th = Thienyl; th = 2,5-thiendiyl; Fc = ferrocenyl; fc = 1,1'-ferrocenediyl). Electrochemical investigations were carried out on these complexes to get a closer insight into the electronic properties of 1, 2, 4 and 5. Typical electrode reactions could be found for the carbene reductions itself and for the tungsten carbonyl oxidation processes in all metal carbene complexes. However, for the thiophene complex 2 two well-separated one-electron reduction events were observed, suggesting an interaction of the Fischer carbene moieties in 2(-), over the thiophene bridge. Reversible one-electron redox events for the ferrocenyl moieties in complexes 4 and 5 were also observed. During the UV Vis NIR spectroelectrochemical investigations typical low energy absorptions for the mixed-valent alpha,alpha'-diferrocenyl thiophene increment were found for these two complexes, as well as high energy NIR absorptions, which were attributed to metal metal charge transfer transition between the tungsten carbonyl increment and the ferrocenyl units (complexes 4 and 5). Further infrared spectroelectrochemical studies reveal that the electronic interactions between the tungsten carbene and the ferrocenyl electrophores in the corresponding cationic species (4(+), 4(2+), 5(+), 5(2+)) can be described with weakly coupled class II systems according to Robin and Day. (c) 2014 Elsevier BY. All rights reserved.

AB - A series of thiophene tungsten Fischer carbene complexes of type [(CO)(5)W=C(OMe)R] (1, R = 2 Th; 4, R = fcthFc) and [(CO)(5)W=C(OMe)-R'-(OMe)C=W(CO)(5)] (2, R' = th; 5, R' = fcthfc) was synthesized for investigating low energy charge transfer interactions between the carbene substituents and the transition metal carbonyl fragment incorporating the thiophene heterocyclic system (Th = Thienyl; th = 2,5-thiendiyl; Fc = ferrocenyl; fc = 1,1'-ferrocenediyl). Electrochemical investigations were carried out on these complexes to get a closer insight into the electronic properties of 1, 2, 4 and 5. Typical electrode reactions could be found for the carbene reductions itself and for the tungsten carbonyl oxidation processes in all metal carbene complexes. However, for the thiophene complex 2 two well-separated one-electron reduction events were observed, suggesting an interaction of the Fischer carbene moieties in 2(-), over the thiophene bridge. Reversible one-electron redox events for the ferrocenyl moieties in complexes 4 and 5 were also observed. During the UV Vis NIR spectroelectrochemical investigations typical low energy absorptions for the mixed-valent alpha,alpha'-diferrocenyl thiophene increment were found for these two complexes, as well as high energy NIR absorptions, which were attributed to metal metal charge transfer transition between the tungsten carbonyl increment and the ferrocenyl units (complexes 4 and 5). Further infrared spectroelectrochemical studies reveal that the electronic interactions between the tungsten carbene and the ferrocenyl electrophores in the corresponding cationic species (4(+), 4(2+), 5(+), 5(2+)) can be described with weakly coupled class II systems according to Robin and Day. (c) 2014 Elsevier BY. All rights reserved.

KW - Spectroelectrochemistry

KW - Metal-metal interaction

KW - Ferrocenyl

KW - 2,5-Diferrocenylthiophene

KW - Tungsten Fischer carbene complexes

KW - SOLID-STATE STRUCTURE

KW - CHARGE-TRANSFER

KW - BISCARBENE COMPLEXES

KW - ELECTRONIC-STRUCTURE

KW - NONAQUEOUS SOLVENTS

KW - DELTA-E-1/2 VALUES

KW - CYCLIC VOLTAMMETRY

KW - RADICAL CATIONS

KW - TRANSITION

KW - FERROCENE

U2 - 10.1016/j.jorganchem.2014.08.025

DO - 10.1016/j.jorganchem.2014.08.025

M3 - Article

VL - 772

SP - 18

EP - 26

JO - Journal of Organometallic Chemistry

JF - Journal of Organometallic Chemistry

SN - 0022-328X

ER -