Catalysis by design: Wide bite angle diphosphines by assembly of ditopic ligands for selective rhodium catalyzed hydroformylation

INOR 563

Zoraida Freixa, zfreixa@iciq.es, Piet WNM van Leeuwen, pvanleeuwen@iciq.es, and David Rivillo. Institute of Chemical Research of Catalonia, ICIQ, Av. Països Catalans 16, 43007, Tarragona, Spain
Ditopic ligands of the general formula N-O--P or N-N--P, in which N-O or N-N is an anionic ligand and P represents a phosphine can be assembled with hard metals such as zinc(II) to form bidentate phosphine ligands. A properly designed N-O--P ditopic ligand (salicylidene-3-diphenylphosphinoaniline) with zinc as the assembly metal gave selective rhodium hydroformylation catalysts for 1-octene with linear to branched ratios up to 21 and rates comparable to covalently bound wide bite angle diphosphines such as Xantphos, while the monodentate ligand in the absence of the "construction" metal gave linearities similar to triphenyl phosphine (2-3). This change in selectivity can be asigned to the preferred bis-equatorial coordination mode in the presence of the assembly metal. The change in coordinaton mode was also observed in operando IR spectroscopy.
 

Organometallic Catalysts
1:30 PM-5:20 PM, Tuesday, August 21, 2007 BCEC -- 211, Oral

Division of Inorganic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007