Reactivity of Cubane-Type [(OC)3MFe3S4(SR)3]3- Clusters (M = Mo, W): Interconversion with Cuboidal [Fe3S4]0 Clus
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- 作者：James W. Raebiger ; Charles A. Crawford ; Jian Zhou ; and R. H. Holm
- 刊名：Inorganic Chemistry
- 出版年：1997
- 出版时间：March 12, 1997
- 年：1997
- 卷：36
- 期：6
- 页码：994 - 1003
- 全文大小：435K
- 年卷期：v.36,no.6(March 12, 1997)
- ISSN：1520-510X
文摘
The title clusters, several examples of which have been reportedearlier, have been prepared by two differentmethods and subjected to structural and reactivity studies. Thecompounds(Et4N)3[(OC)3MFe3S4(Smes)3]·MeCN(M = Mo/W) are isomorphous and crystallize in monoclinic space groupP21/n with a =13.412(1)/13.297(1) Å,b = 19.0380(1)/18.9376(3) Å, c =26.4210(1)/26.2949(1) Å, 
=97.87(1)/97.549(1)
, and Z = 4. Theclusterscontain long M-S (2.62/2.59 Å) and M-Fe (3.22/3.19 Å) bonds,consistent with the reported structure of[(OC)3MoFe3S4(SEt)3]3-(3). Reaction of[(OC)3MoFe3S4(LS3)]3-(7) with CO in the presence of NaPF6affordscuboidal[Fe3S4(LS3)]3-(9), also prepared in this laboratory by another route as asynthetic analogue of protein-bound [Fe3S4]0 clusters. Theclusters[Fe3S4(SR)3]3-(R = mes, Et), of limited stability, were generated bythesame reaction. Treatment of 9 with[M(CO)3(MeCN)3] affords 7 andits M = W analogue. The clusters[(OC)3MFe3S4(SR)3]3-form a four-member electron transfer series in which the 3- clustercan be once reduced(4-) and twice oxidized (2-, 1-) to afford clusters of theindicated charges. The correct assignment of redoxcouple to potential in the redox series of six clusters is presented,correcting an earlier misassignment of theredox series of 3. Carbonyl stretching frequencies areshown to be sensitive to cluster oxidation state, showingthat the M sites and Fe3S4 fragments areelectronically coupled despite the long bond distances.(LS3 = 1,3,5-tris((4,6-dimethyl-3-mercaptophenyl)thio)-2,4,6-tris(p-tolylthio)benzenate(3-);mes = mesityl.)
=97.87(1)/97.549(1), and Z = 4. Theclusterscontain long M-S (2.62/2.59 Å) and M-Fe (3.22/3.19 Å) bonds,consistent with the reported structure of[(OC)3MoFe3S4(SEt)3]3-(3). Reaction of[(OC)3MoFe3S4(LS3)]3-(7) with CO in the presence of NaPF6affordscuboidal[Fe3S4(LS3)]3-(9), also prepared in this laboratory by another route as asynthetic analogue of protein-bound [Fe3S4]0 clusters. Theclusters[Fe3S4(SR)3]3-(R = mes, Et), of limited stability, were generated bythesame reaction. Treatment of 9 with[M(CO)3(MeCN)3] affords 7 andits M = W analogue. The clusters[(OC)3MFe3S4(SR)3]3-form a four-member electron transfer series in which the 3- clustercan be once reduced(4-) and twice oxidized (2-, 1-) to afford clusters of theindicated charges. The correct assignment of redoxcouple to potential in the redox series of six clusters is presented,correcting an earlier misassignment of theredox series of 3. Carbonyl stretching frequencies areshown to be sensitive to cluster oxidation state, showingthat the M sites and Fe3S4 fragments areelectronically coupled despite the long bond distances.(LS3 = 1,3,5-tris((4,6-dimethyl-3-mercaptophenyl)thio)-2,4,6-tris(p-tolylthio)benzenate(3-);mes = mesityl.)