The synthesis and characterisation of a series of linear triphos {PhP(CH2CH2PPh2)2} bridged iron/tungsten or molybdenum bimetallic complexes

The reaction of [Fe2(CO)9] with 2 equiv. of La,b,c {La,b,c=[MX2(CO){PhP(CH2CH2PPh2)2-P,P′}(η2-RC2R′)] {M=W, X=I; La, R=R′=Me; Lb=R=R′=Ph; Lc=R=Me, R′=Ph} in CH2Cl2 at room temperature gives the bimetallic linear triphos-bridged complexes [Fe(CO)4La,b,c] (1–3) in good yield. Equimolar quantities of [FeI(CO)2Cp or Cp′] and La,b,c,d,e,f (Ld, M=Mo, X=I, R=R′=Me; Le, M=Mo, X=I, R=R′=Ph; Lf, M=W, X=Br, R=R′=Ph) react in CH2Cl2 at room temperature to afford the cationic phosphine-bridged complexes [Fe(CO)2(La,b,c,d,e,f)(Cp or Cp′)]I (for La,b,c, Cp or Cp′; for Ld,e,f, Cp only) 4–12 in good yield. Treatment of [Fe(CO)2LaCp]I with 1 equiv. of Na[BPh4] in CH2Cl2 at room temperature yields the iodide exchanged product, [Fe(CO)2LaCp][BPh4] (13). Equimolar quantities of [Fe(CO)4La] and L {L=CNBut or P(OMe)3} gives the iron-carbonyl substituted products [Fe(CO)3LLa] (14–15) in good yield. Complexes 1–15 have been characterised by elemental analysis (C, H and N), IR and 1H and 31P NMR spectroscopy.