OPEN AND CLOSED P-FUNCTIONALIZED DIFERRIOPHOSPHONIUM SALTS OF THE TYPE [(CPFE(CO)2)2P(PH)R]+X- AND [(MU-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 KOBu(t) at -78-degrees-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 1 b-f are found to eliminate readily a CO ligand upon photolysis to give the corresponding closed P-functionalized diferriophosphonium salts [{mu-CO(CpFeCO)2}P(Ph)R]X (2 b-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 [{mu-CO(CpFeCO)2}PPh2]BPh4 (2 b') are reported and discussed.