Phosphorus- and arsenic-bridged [1]ferrocenophanes. 3. Hydroformylation catalyzed by the products of the interaction of Co2(CO)8 with 1,1′-ferrocenylenephenylphosphine oligomers and polymers

Article abstract of DOI:10.1021/om50001a007

Reactions of Co₂(CO)₈ with ferrocenylphosphine oligomers of the type H[-(η⁵-C₅H₄)Fe(η⁵-C ₅H₄PPh)-]_xPh (I, x= 1-4) and Ph₂P[-(η⁵-C₅H₄)Fe(η ⁵-C₅H₄PPh)-]_XPh (III, x = 1, 2) or polymers of the type, H[-(η⁵-C₅H₄)Fe(η⁵-C ₅H₄PPh)-]_x]OH (II, M?_w 8900-161 000 amu) have been studied. Detailed IR and ³¹P NMR spectroscopic investigations revealed that the polymeric ligands chelate Co in a tridentate fashion, similar to I (x = 3) when a high P/Co ratio is used. Use of such Co catalysts at 170-190°C for the hydroformylation of 1-hexene revealed reactivity and selectivity similar to those of PPh₃ for ligands of type I and type III, while Co complexes of the polymers, II, demonstrated a M?_w-dependent activity and a lower selectivity to alcohols. It is felt that the observed tendency for tridentate chelation in these complexes inhibits the aldehyde-to-alcohol reduction step. A ³¹P NMR study of the cobalt complex of the trimer I (x = 3) provided evidence for the presence of two enantiomeric isomers and selective quadrupolar broadening in the equatorial direction.