Isomerization mechanism of dinuclear chloro-bridged rhodium(I) complexes
1994; Elsevier BV; Volume: 13; Issue: 17 Linguagem: Inglês
10.1016/s0277-5387(00)83091-0
ISSN1873-3719
AutoresGiuseppe Giordano, Enrico Rotondo,
Tópico(s)Catalytic Cross-Coupling Reactions
ResumoAt room temperature the cis- and trans-halide-bridged dimers [{Rh(CO) (PPh3)(μ-Cl)}2] give rise to a rather fast equilibrium of interconversion. NMR spectra provide evidence that during the reaction neither rhodium-phosphorus nor rhodium-carbon bonds are broken. These results suggest that the equilibrium takes place through dissociation of the dinuclear Rh1 species into the tricoordinated 14-electron T-shaped fragments [Rh(CO)(PPh3)Cl]. In keeping with this suggestion, the rate of the isomerization is accelerated by the presence in solution of small amounts of cis-[Rh(CO)2(PPh3)(μ-Cl)], a complex which can be considered a precursor of the tricoordinated fragment [Rh(CO)(PPh3)Cl].
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