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Chalcogenide-capped triiron clusters [Fe3(CO)93-E)2], [Fe3(CO)73-CO)(μ3-E)(μ-dppm)] and [Fe3(CO)73-E)2(μ-dppm)] (E = S, Se) as proton-reduction catalysts

Rahaman, Ahibur LU ; Ghosh, Shishir; Basak-Modi, Sucharita; Abdel-Magied, Ahmed F.; Kabir, Shariff E.; Haukka, Matti; Richmond, Michael G.; Lisensky, George C. LU ; Nordlander, Ebbe LU and Hogarth, Graeme (2019) In Journal of Organometallic Chemistry 880. p.213-222
Abstract

Chalcogenide-capped triiron clusters [Fe3(CO)73-CO)(μ3-E)(μ-dppm)] and [Fe3(CO)73-E)2(μ-dppm)] (E = S, Se) have been examined as proton-reduction catalysts. Protonation studies show that [Fe3(CO)93-E)2] are unaffected by strong acids. Mono-capped [Fe3(CO)73-CO)(μ3-E)(μ-dppm)] react with HBF4.Et2O but changes in IR spectra are attributed to BF3 binding to the face-capping carbonyl, while bicapped [Fe3(CO)73-E)2(μ-dppm)] are protonated but in a process that is not catalytically... (More)

Chalcogenide-capped triiron clusters [Fe3(CO)73-CO)(μ3-E)(μ-dppm)] and [Fe3(CO)73-E)2(μ-dppm)] (E = S, Se) have been examined as proton-reduction catalysts. Protonation studies show that [Fe3(CO)93-E)2] are unaffected by strong acids. Mono-capped [Fe3(CO)73-CO)(μ3-E)(μ-dppm)] react with HBF4.Et2O but changes in IR spectra are attributed to BF3 binding to the face-capping carbonyl, while bicapped [Fe3(CO)73-E)2(μ-dppm)] are protonated but in a process that is not catalytically important. DFT calculations are presented to support these protonation studies. Cyclic voltammetry shows that [Fe3(CO)93-Se)2] exhibits two reduction waves, and upon addition of strong acids, proton-reduction occurs at a range of potentials. Mono-chalcogenide clusters [Fe3(CO)73-CO)(μ3-E)(μ-dppm)] (E = S, Se) exhibit proton-reduction at ca. -1.85 (E = S) and -1.62 V (E = Se) in the presence of p-toluene sulfonic acid (p-TsOH). Bicapped [Fe3(CO)73-E)2(μ-dppm)] undergo quasi-reversible reductions at -1.55 (E = S) and -1.45 V (E = Se) and reduce p-TsOH to hydrogen but protonated species do not appear to be catalytically important. Current uptake is seen at the first reduction potential in each case, showing that [Fe3(CO)73-E)2(μ-dppm)]- are catalytically active but a far greater response is seen at ca. -1.9 V being tentatively associated with reduction of [H2Fe3(CO)73-E)2(μ-dppm)]+. In general, selenide clusters are reduced at slightly lower potentials than sulfide analogues and show slightly higher current uptake under comparable conditions.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Chalcogenide, Cluster, Electrochemistry, Proton-reduction, Triiron
in
Journal of Organometallic Chemistry
volume
880
pages
10 pages
publisher
Elsevier
external identifiers
  • scopus:85056623912
ISSN
0022-328X
DOI
10.1016/j.jorganchem.2018.10.018
language
English
LU publication?
yes
id
7432758e-dbd7-4d86-8562-cb782e121c41
date added to LUP
2018-11-26 11:55:22
date last changed
2019-10-23 06:03:48
@article{7432758e-dbd7-4d86-8562-cb782e121c41,
  abstract     = {<p>Chalcogenide-capped triiron clusters [Fe<sub>3</sub>(CO)<sub>7</sub>(μ<sub>3</sub>-CO)(μ<sub>3</sub>-E)(μ-dppm)] and [Fe<sub>3</sub>(CO)<sub>7</sub>(μ<sub>3</sub>-E)<sub>2</sub>(μ-dppm)] (E = S, Se) have been examined as proton-reduction catalysts. Protonation studies show that [Fe<sub>3</sub>(CO)<sub>9</sub>(μ<sub>3</sub>-E)<sub>2</sub>] are unaffected by strong acids. Mono-capped [Fe<sub>3</sub>(CO)<sub>7</sub>(μ<sub>3</sub>-CO)(μ<sub>3</sub>-E)(μ-dppm)] react with HBF<sub>4</sub>.Et<sub>2</sub>O but changes in IR spectra are attributed to BF<sub>3</sub> binding to the face-capping carbonyl, while bicapped [Fe<sub>3</sub>(CO)<sub>7</sub>(μ<sub>3</sub>-E)<sub>2</sub>(μ-dppm)] are protonated but in a process that is not catalytically important. DFT calculations are presented to support these protonation studies. Cyclic voltammetry shows that [Fe<sub>3</sub>(CO)<sub>9</sub>(μ<sub>3</sub>-Se)<sub>2</sub>] exhibits two reduction waves, and upon addition of strong acids, proton-reduction occurs at a range of potentials. Mono-chalcogenide clusters [Fe<sub>3</sub>(CO)<sub>7</sub>(μ<sub>3</sub>-CO)(μ<sub>3</sub>-E)(μ-dppm)] (E = S, Se) exhibit proton-reduction at ca. -1.85 (E = S) and -1.62 V (E = Se) in the presence of p-toluene sulfonic acid (p-TsOH). Bicapped [Fe<sub>3</sub>(CO)<sub>7</sub>(μ<sub>3</sub>-E)<sub>2</sub>(μ-dppm)] undergo quasi-reversible reductions at -1.55 (E = S) and -1.45 V (E = Se) and reduce p-TsOH to hydrogen but protonated species do not appear to be catalytically important. Current uptake is seen at the first reduction potential in each case, showing that [Fe<sub>3</sub>(CO)<sub>7</sub>(μ<sub>3</sub>-E)<sub>2</sub>(μ-dppm)]<sup>-</sup> are catalytically active but a far greater response is seen at ca. -1.9 V being tentatively associated with reduction of [H<sub>2</sub>Fe<sub>3</sub>(CO)<sub>7</sub>(μ<sub>3</sub>-E)<sub>2</sub>(μ-dppm)]<sup>+</sup>. In general, selenide clusters are reduced at slightly lower potentials than sulfide analogues and show slightly higher current uptake under comparable conditions.</p>},
  author       = {Rahaman, Ahibur and Ghosh, Shishir and Basak-Modi, Sucharita and Abdel-Magied, Ahmed F. and Kabir, Shariff E. and Haukka, Matti and Richmond, Michael G. and Lisensky, George C. and Nordlander, Ebbe and Hogarth, Graeme},
  issn         = {0022-328X},
  keyword      = {Chalcogenide,Cluster,Electrochemistry,Proton-reduction,Triiron},
  language     = {eng},
  pages        = {213--222},
  publisher    = {Elsevier},
  series       = {Journal of Organometallic Chemistry},
  title        = {Chalcogenide-capped triiron clusters [Fe<sub>3</sub>(CO)<sub>9</sub>(μ<sub>3</sub>-E)<sub>2</sub>], [Fe<sub>3</sub>(CO)<sub>7</sub>(μ<sub>3</sub>-CO)(μ<sub>3</sub>-E)(μ-dppm)] and [Fe<sub>3</sub>(CO)<sub>7</sub>(μ<sub>3</sub>-E)<sub>2</sub>(μ-dppm)] (E = S, Se) as proton-reduction catalysts},
  url          = {http://dx.doi.org/10.1016/j.jorganchem.2018.10.018},
  volume       = {880},
  year         = {2019},
}