Synthesis, Structural Characterization, and Hydroformylation Activity of Rhodium(I) Complexes with a Polar Phosphinoferrocene Sulfonate Ligand

Abstract

1′-(Diphenylphosphino)ferrocene-1-sulfonic acid (HL), isolated from the salt (Et3NH)L on an ion exchanger, reacts with Rh(I) complexes [Rh(acac)(CO)(PR3)] (acac = acetylacetonato-κ2O,O′) to give complexes of the type [Rh(CO)(PR3)(Ph2PfcSO3-κ2O,P)] (1a–d; R = Ph (a), Cy (b), 2-furyl (c), and OMe (d); fc = ferrocene-1,1′-diyl). In an analogous reaction with [Rh(acac)(nbd)] (nbd = η2:η2-norbornadiene), HL produces [Rh(nbd)(Ph2PfcSO3-κ2O,P)] (2). Adding (Et3NH)L (2 equiv per Rh) to [Rh(μ-Cl)(CO)2]2 and [Rh(acac)(CO)2] gives rise to the cationic complexes trans-(Et3NH)2[RhCl(CO)(Ph2PfcSO3-κP)2] (3) and (Et3NH)[Rh(CO)(Ph2PfcSO3-κ2O,P)(Ph2PfcSO3-κP)] (4), respectively. In complex 4, resulting from the simultaneous substitution of a CO ligand and acid–base replacement of the acac ligand, the P-monodentate and O,P-chelating phosphinoferrocene sulfonate ligands rapidly interconvert (in a solution). All compounds were characterized by spectroscopic methods and by elemental analysis, and the crystal structures of 1a·...