| Abstract
| - The one-pot reaction of 2 equiv of CpFe(CO)2I and 1,1‘-dilithioferrocene in the presence of 2 equiv of PPh3 proceeds through [CpFe(CO)2PPh3+] and yields 4 in 51% yield, where 1,1‘-dilithioferrocene participates twice in the nucleophilic Fc-additions: at the Cp-ring and at a CO ligand of [CpFe(CO)2PPh3+]. The ferrocenediyl-bridged tri-Fe complex 4 has three different Fe-centers: a metallocene Fe(II), a square-pyramidal pentacoordinate Fe(0), and a half-sandwich acyl-Fe(II).
- The reaction of 2 equiv of CpFe(CO)2I and 1,1‘-dilithioferrocene in the presence of 2 equivof PPh3 is an intermolecular version of the reaction of CpFe(CO)2I and (η5-C5H4Li)Fe(C5H4PPh2). In the three-component procedure, the PPh3 substitution for iodide on CpFe(CO)2I ismuch faster than the nucleophilic Fc-addition at the Fe-center or at a CO ligand of CpFe(CO)2I. This one-pot reaction proceeds through [CpFe(CO)2PPh3+] and yields CpFe(CO)(PPh3)[μ,C:η5-C(O)C5H4]Fe[μ,η5:η4-5-exo-(1‘-C5H4)C5H5]Fe(CO)2(PPh3) (4) in 50% yield, with the 1,1‘-dilithioferrocene participating twice in the nucleophilic Fc-additions: at the Cp-ring and ata CO ligand of [CpFe(CO)2PPh3+]. Complex 4 is a ferrocenediyl-bridged tri-Fe complex withthree different Fe-centers: a metallocene Fe(II), a square-pyramidal pentacoordinate Fe(0),and a half-sandwich acyl-Fe(II). It has been found that, in the second Fc-additions, thepathway from (η5-C5H4Li)Fe[μ,η5:C-C5H4C(O)]FeCp(CO)(PPh3) (9) to 4 proceeds normally,but the pathway from 9 to Fe[(μ,η5:C-C5H4)C(O)FeCp(CO)(PPh3)]2 (5) has been turned off.The preference of Fc-addition for 9 onto the Cp-ring of [CpFe(CO)2PPh3+] could be reasonedby a localization of the Li+ cation in 9.
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