Bis(Diphenylphospino)methane-substituted Products from (m3-CCH3)Co3(CO)9

The reaction between the alkylidyne cluster (μ3-CCH3)Co3(CO)9 and bis(diphenylphosphino) (dppm) gives two disubstituted stereoisomers of formula (μ3-CCH3)Co3(CO)7(μ-PPh2CH2PPh2) (I and II) and one monosubstituted product containing an uncoordinated phosphoryl group, (μ3-CCH3)Co3(CO)8[PPh2-CH2P(O)Ph2] (III). On heating in toluene under reflux, the kinetically favoured isomer I is transformed into the thermodynamically stable isomer II. Further reaction with a second molecule of dppm gives rise to two derivatives, (μ3-CCH3)CO3(CO)5(μ-dppm)2 (IV) and (μ3-CCH3)Co3(CO)6(μ-dppm)(dppm) (V). All the products have been characterized by IR and 13C and 31P NMR spectroscopy.