Synthesis and characterization of mixed-ligand ferracarboranes. Direct metalation of the nido-carborane [nido-7,8-C2B9H12]− mono-anion with 14-e [Ph2P(CH2)nPPh2]FeCl2 (n = 2, 3)

The heating of a mixture of 14-e [Ph2P(CH2)nPPh2]FeCl2 (n = 3 or 2) with the [K]+ salt of the [nido-7,8-C2B9H12]− mono-anion under gentle reflux in benzene affords either the paramagnetic (17-electron) complex [3,3-(dppp)-3-Cl-closo-3,1,2-FeC2B9H11] isolated in 15% yield or a mixture of the paramagnetic complex [3,3-(dppe)-3-Cl-closo-3,1,2-FeC2B9H11] (46% yield) and the diamagnetic complex [commo-8,8′-μ-(Ph2PCH2CH2PPh2)-3,3′-Fe{1,2-C2B9H10}2] (10% yield). All three novel ferracarboranes were characterized by spectroscopic (EPR or NMR) data and single-crystal X-ray diffraction.