dc.contributor.author |
Bezuidenhout, Daniela Ina
|
|
dc.contributor.author |
Fernandez, Israel
|
|
dc.contributor.author |
Van der Westhuizen, Belinda
|
|
dc.contributor.author |
Swarts, Pieter J.
|
|
dc.contributor.author |
Swarts, Jannie C.
|
|
dc.date.accessioned |
2014-02-13T06:22:48Z |
|
dc.date.issued |
2013-12 |
|
dc.description.abstract |
The series [(CO)5W=C(XR)Fc], 1 (XR = OEt) and 3 (XR = NHBu) as well as
[(CO)5W=C(XR)-Fc'-(XR)C=W(CO)5], 2 (XR = OEt) and 4 (XR = NHBu) of mono- and
biscarbene tungsten(0) complexes with Fc = FeII(C5H5)(C5H4) for monosubstituted derivatives
and Fc¢ = FeII(C5H4)2 for disubstituted derivatives were synthesized and characterized
spectroscopically. The oxidized ferrocenium complex [1+]•PF6 was also synthesized and
characterized. Electrochemical and computational studies were mutually consistent in confirming
the sequence of redox events for the carbene derivatives 1 - 4 as first a carbene double bond reduction to a radical anion, -W-C•, at peak cathodic potentials smaller than -2 V, then a
ferrocenyl group oxidation in the range 0.206 < Eo' < 0.540 V and finally an electrochemically
irreversible three-electron W(0) oxidation at Epa > 0.540 V vs. FcH/FcH+ in CH2Cl2 /
[(nBu4)N][PF6]. This contrasts the sequence of oxidation events in ferrocenylcarbene complexes
of chromium where Cr(0) is first oxidised in a one electron transfer process, then the ferrocenyl
group, and finally formation of a Cr(II) species. The unpaired electron of the reductively formed
radical anion is mainly located on the carbene carbon atom. Electronic interactions between two
carbene double bonds (for biscarbenes 2 and 4) as well as between two W centers (for 4) were
evident. Differences in redox potentials between the “a” and “b” components of the threeelectron
W oxidation of 4 in CH2Cl2 or CH3CN / [(nBu4)N][PF6] are DEo' = Epa W(0) oxd 1b – Epa W(0)
oxd 1a = ca. 51 and 337 mV respectively. Tungsten oxidation was restricted to a W0/II couple in
CH2Cl2 / [(nBu4)N][B(C6F5)4]. From the computational results, the short-lived W(II) species
were observed to be stabilized by agostic CH···W interactions. |
en_US |
dc.description.librarian |
hb2014 |
en_US |
dc.description.sponsorship |
National Research Foundation, South Africa, (DIB, Grant number 76226;
JCS, Grant number 81829), and by the Spanish MICINN and CAM (IF, Grants CTQ2010-20714-CO2-01/BQU, Consolider-Ingenio 2010, CSD2007-00006, S2009/PPQ-1634). |
en_US |
dc.description.uri |
http://pubs.acs.org/journal/orgnd7 |
en_US |
dc.identifier.citation |
Bezuidenhout, DI, Fernandez, I, Van der Westhuizen, B, Swarts, PJ & Swarts, JC 2013, 'Electrochemical and computational study of tungsten(0) ferrocene complexes: observation of the mono-oxidized tungsten(0) ferrocenium species and intramolecular electronic interactions', Organometallics, vol. 32, no. 24, pp. 7334-7344. |
en_US |
dc.identifier.issn |
0276-7333 (print) |
|
dc.identifier.issn |
1520-6041 (online) |
|
dc.identifier.other |
10.1021/om400865m |
|
dc.identifier.uri |
http://hdl.handle.net/2263/33409 |
|
dc.language.iso |
en |
en_US |
dc.publisher |
American Chemical Society |
en_US |
dc.rights |
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Organometallics. Copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see : Electrochemical and computational study of tungsten(0) ferrocene complexes : observation of the mono-oxidized tungsten(0) ferrocenium species and intramolecular electronic interactions in Organometallics, vol. 32, no. 24, pp. 7334-7344, 2013. doi : 10.1021/om400865m. Articles on Request author-directed link to Published Work, see : http://pubs.acs.org/doi/abs/10.1021/om400865m?prevSearch=%255BContrib%253A%2Bbezuidenhout%255D&searchHistoryKey= |
en_US |
dc.subject |
Electrochemical |
en_US |
dc.subject |
Computational study |
en_US |
dc.subject |
Observation |
en_US |
dc.subject |
Intramolecular electronic |
en_US |
dc.subject |
Interactions |
en_US |
dc.title |
Electrochemical and computational study of tungsten(0) ferrocene complexes: observation of the mono-oxidized tungsten(0) ferrocenium species and intramolecular electronic interactions |
en_US |
dc.type |
Postprint Article |
en_US |