110935-15-4Relevant academic research and scientific papers
Study of ethylidyne-alkyne coupling on the trinuclear iron cluster, Fe3(CO)10(μ-H)(μ-CCH3)
Nuel, Didier,Mathieu, René
, p. 16 - 21 (2008/10/08)
The reaction of HFe3(μ-CCH3)(CO)10 with alkynes is highly dependent on the nature of the alkyne. With monosubstituted alkynes, RC≡CH, three types of complexes have been isolated from refluxing hexane: Fe3(μ3-η2-⊥-CH3CCCH 2R)(CO)9 (R = H (2) or C(CH3)3 (5)), Fe3(μ3-CCH3)(μ3-CCH 2R)(CO)9 (R = C(CH3)3) (6), and HFe3[μ3-η3-C(CH 3)C(R)CH](CO)9 (R = C6H5) (8). It has been shown that complexes 5 and 6 cannot be interconverted under the reaction conditions used for their synthesis and a mechanism for their formation is proposed. Complex 8 with R = C6H5 shows an interesting thermal evolution leading to Fe3(CO)6(μ-CO)2[CHC(C2H 5)C(CH)4C] (9) through an Fe2(CO)6[CHC(C2H5)C(CH) 4C] [μ-Fe(CO)3] (10) intermediate, which implies the breaking of two Fe-Fe bonds and the formation of one Fe-Fe bond facilitated by coordination of a Fe(CO)3 fragment to the phenyl ring. The ferracyclopentadiene ring of these two compounds results from the hydrogenation of the CCH3 group, the hydrogen atom being provided by the orthometalation of the phenyl ring and hydride ligand. In the case of RCCR alkynes, fragmentation of the cluster is observed and two types of dinuclear complexes are isolated: Fe2(CO)6(CRCRCCH3CRCRH) (R = CH3 or C6H5) and Fe2(CO)6(CCH3CRCRH) (R = C6H5).
