Offene und geschlossene P-funktionalisierte Diferriophosphonium-Salze des Typs [ { CpFe(CO)2}2P(Ph)R]+ X⁻ bzw. [ {μ-CO(CpFeCO)2} P(Ph)R]+ X⁻ / Open and Closed P-Functionalized Diferriophosphonium Salts of the Type [{CpFe(CO)2}2P(Ph)R]+ X⁻ and [{ μ-CO(CpFeCO)2}P(Ph)R]+ X⁻

The reaction of Ph(R)PSiMe3 with an excess of CpFe(CO)2Cl results in the elimination of Me3SiCl to give the open diferriophosphonium halides [{CpFe(CO)2}2P(Ph)R]Cl (R = H, Ph, CH2SiMe3, Me) (1 a—d). The deprotonation reaction of 1 a with KOBut at —78°C results in the formation of the unstable diferriophosphane {CpFe(CO)2}2PPh (3), which reacts with alkylating reagents RX (R = Me, CH2Ph, CH2COOEt; X = Cl, I) to give the P-functionalized diferriophosphonium halides [{CpFe(CO)2}2P(Ph)R]X (1 d’—f). The light-sensitive compounds 1b—f are found to eliminate readily a CO ligand upon photolysis to give the corresponding closed P-functionalized diferriophosphonium salts [{µ-CO(CpFeCO)2}P(Ph)R]X (2b—f) with a bridging CO ligand and a Fe— Fe bond. The mass, IR and NMR spectra of 1, 2 and the results of a crystal structure determination of [{μ-CO(CpFeCO)2}PPh2]BPh4 (2b’) are reported and discussed.