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⁻

Abstract

The reaction of Ph(R)PSiMe 3 with an excess of CpFe(CO) 2 Cl results in the elimination of Me 3 SiCl to give the open diferriophosphonium halides [{CpFe(CO) 2 } 2 P(Ph)R]Cl (R = H, Ph, CH 2 SiMe 3 , Me) (1 a—d). The deprotonation reaction of 1 a with KOBu t at —78°C results in the formation of the unstable diferriophosphane {CpFe(CO) 2 } 2 PPh (3), which reacts with alkylating reagents RX (R = Me, CH 2 Ph, CH 2 COOEt; X = Cl, I) to give the P-functionalized diferriophosphonium halides [{CpFe(CO) 2 } 2 P(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 }PPh 2 ]BPh 4 (2b’) are reported and discussed.