Top Organomet Chem (2016) 59: 1–30
DOI: 10.1007/3418_2015_147
# Springer International Publishing Switzerland 2016
Published online: 18 February 2016
Bimetallic Homogeneous Hydroformylation
Ranelka G. Fernando, Ciera D. Gasery, Marshall D. Moulis,
and George G. Stanley
Abstract A dirhodium hydrido-carbonyl catalyst system based on a binuclating
tetraphosphine ligand is discussed. Spectroscopic and DFT computational studies
support the formulation of the key catalyst complex in acetone solvent as [Rh 2 (μH) 2 (CO) 2 (rac-P4)]
2+ , which is highly active and regioselective for producing linear
aldehydes under mild conditions. This dicationic catalyst suffers from facile fragmentation reactions in acetone that lead to inactive monometallic and bimetallic
complexes. The addition of water to the acetone solvent leads to deprotonation from
the dicationic catalyst to form monocationic dirhodium catalyst species that are far
less susceptible to deactivation. Spectroscopic and DFT computational studies
indicate that the key monocationic catalyst is [Rh 2 (μ-H)(CO) 3 (rac-P4)]
+
. Although
the monocationic bimetallic catalyst is less active on a per molecule basis relative to
the dicationic catalyst, there is a higher concentration present producing better
overall catalyst rates and selectivity.
Keywords Bimetallic cooperativity • DFT calculations • Hydrides •
Hydroformylation (oxo) • Phosphines • Rhodium • Spectroscopic studies
Contents
1 Introduction: Hydroformylation and Polymetallic Cooperativity . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Dirhodium Tetraphosphine Hydroformylation Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Dicationic Dirhodium Catalyst in Acetone Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 Hydroformylation in Water/Acetone: Formation of a Monocationic Dirhodium
Catalyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5 Catalyst Binding Site Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
6 Future Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
R.G. Fernando, C.D. Gasery, M.D. Moulis, and G.G. Stanley (*)
Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803-1804, USA
e-mail: gstanley@lsu.edu
DOI: 10.1007/3418_2015_147
# Springer International Publishing Switzerland 2016
Published online: 18 February 2016
Bimetallic Homogeneous Hydroformylation
Ranelka G. Fernando, Ciera D. Gasery, Marshall D. Moulis,
and George G. Stanley
Abstract A dirhodium hydrido-carbonyl catalyst system based on a binuclating
tetraphosphine ligand is discussed. Spectroscopic and DFT computational studies
support the formulation of the key catalyst complex in acetone solvent as [Rh 2 (μH) 2 (CO) 2 (rac-P4)]
2+ , which is highly active and regioselective for producing linear
aldehydes under mild conditions. This dicationic catalyst suffers from facile fragmentation reactions in acetone that lead to inactive monometallic and bimetallic
complexes. The addition of water to the acetone solvent leads to deprotonation from
the dicationic catalyst to form monocationic dirhodium catalyst species that are far
less susceptible to deactivation. Spectroscopic and DFT computational studies
indicate that the key monocationic catalyst is [Rh 2 (μ-H)(CO) 3 (rac-P4)]
+
. Although
the monocationic bimetallic catalyst is less active on a per molecule basis relative to
the dicationic catalyst, there is a higher concentration present producing better
overall catalyst rates and selectivity.
Keywords Bimetallic cooperativity • DFT calculations • Hydrides •
Hydroformylation (oxo) • Phosphines • Rhodium • Spectroscopic studies
Contents
1 Introduction: Hydroformylation and Polymetallic Cooperativity . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Dirhodium Tetraphosphine Hydroformylation Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Dicationic Dirhodium Catalyst in Acetone Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 Hydroformylation in Water/Acetone: Formation of a Monocationic Dirhodium
Catalyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5 Catalyst Binding Site Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
6 Future Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
R.G. Fernando, C.D. Gasery, M.D. Moulis, and G.G. Stanley (*)
Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803-1804, USA
e-mail: gstanley@lsu.edu