88904-48-7Relevant academic research and scientific papers
Binuclear phosphide-bridged tungsten-rhodium complexes. Crystal and molecular structure of the dimeric bimetallic complex [(CO)4W(μ-PPh2)2Rh(μ-CO)]2 with a bent metal chain
Shulman, Peter M.,Burkhardt, Eric D.,Lundquist, Eric G.,Pilato, Robert S.,Geoffroy, Gregory L.,Rheingold, Arnold L.
, p. 101 - 109 (2008/10/08)
The new phosphido-bridged W-Rh complexes (CO)4W(μ-PPh2)2RhH(CO)(PPh3) (2), (CO)4W(μ-PPh2)2RhH(COD) (3; COD = 1,5-cyclooctadiene), and (CO)4W(μ-PPh2)2Rh(cyclooctenyl) (4) have been prepared and characterized. Complex 2 has been structurally characterized: P21/n, a = 11.430 (3) A?, b = 19.085 (5) A?, c = 20.738 (6) A?, β = 100.80 (2)°, V - 4444 (2) A?3, Z = 4, R = 0.0393, Rw = 0.0420 for 5754 reflections with Fo > 4σ(Fo). The two μ-PPh2 ligands bridge the W-Rh bond with the W further coordinated by four COs and the Rh by hydride, CO, and PPh3 ligands. Complex 4 reacts with CO to yield the tetrametallic complex [(CO)4W(μ-PPh2)2Rh(μ-CO)]2 (13) which has been structurally characterized: P1, a = 13.580 (2) A?, b = 19.838 (4) A?, c = 22.299 (5) A?, α = 82.94 (2)°, β = 79.17 (2)°, γ = 88.63 (2)°, V = 5857 (2) A?3, Z = 4, R = 0.0619, Rw = 0.0699 for 6749 reflections with Fo > 3σ(Fo). Two crystallographically independent but chemically similar molecules form the asymmetric unit; the two molecules form an enantiomeric pair. The four metal atoms of each molecule are arranged in a bent chain with the W atoms at the end and the Rh atoms in the middle of the chain, and all metal-metal distances are consistent with single metal-metal bonds. The two Rh's are bridged by two carbonyl ligands, and the W-Rh units are each bridged by two μ-PPh2 ligands. Complex 13 rapidly reacts with CO/H2/PPh3 to cleave the Rh-Rh bond and form complex 2. This latter complex was found to readily react with ethylene to transform one of the μ-PPh2 bridges into a PPh2Et ligand and give (CO)4(PPh2Et)W(μ-PPh2)Rh(CO)(PPh 3). Similar bridge elimination occurs when the anionic complex [(CO)4W(μ-PPh2)2Rh(CO)(PPh 3)]- is treated with CH3OTf.
