[Fe2(SR)2(-CO)(CNMe)6]2+ and Analogues: A New Class of Diiron Dithiolates as Structural Mo
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- 作者：Christine A. Boyke ; Thomas B. Rauchfuss ; Scott R. Wilson ; Marie-Madeleine Rohmer ; and Marc Bé ; nard
- 刊名：Journal of the American Chemical Society
- 出版年：2004
- 出版时间：November 24, 2004
- 年：2004
- 卷：126
- 期：46
- 页码：15151 - 15160
- 全文大小：471K
- 年卷期：v.126,no.46(November 24, 2004)
- ISSN：1520-5126
文摘
Low-temperature oxidation of Fe2(S2CnH2n)(CNMe)6-x(CO)x (n = 2, 3; x = 2, 3) affords a familyof mixed carbonyl-isocyanides of the type [Fe2(S2CnH2n)(CO)x(CNMe)7-x]2+. The degree of substitution iscontrolled by the RNC/Fe ratio, as well as the degree of initial substitution at iron, with tricarbonyl derivativesfavoring more highly carbonylated products. The structures of the monocarbonyl derivatives [Fe2(S2CnH2n)(
ages/entities/mgr.gif">-CO)(CNMe)6](PF6)2 (n = 2,3) established crystallographically and spectroscopically, are quite similar,with Fe---Fe distances of ca. 2.5 Å, although the ages/entities/mgr.gif">-CO is unsymmetrical in the propanedithiolate derivative.Isomeric forms of [Fe2(S2C3H6)(CO)(CNMe)6](PF6)2 were characterized where the CO is bridging or terminal,the greatest structural difference being the 0.1 Å elongation of the Fe---Fe distance when MeNC (vs CO)is bridging. In the dicarbonyl species, [Fe2(S2C2H4)(ages/entities/mgr.gif">-CO)(CO)(CNMe)5](PF6)2, the terminal CO ligand issituated at one of the basal sites, not trans to the Fe---Fe vector. Oxidation of Fe2(S2C2H4)(CNMe)3(CO)3under 1 atm CO gives the deep pink tricarbonyl [Fe2(S2C2H4)(CO)3(CNMe)4](PF6)2. DFT calculations showthat a bridging CO or MeNC establishes a 3-center, 2-electron bond within the two Fe(II) centers, whichwould otherwise be nonbonding.