18956-21-3Relevant articles and documents
The electron-poor phosphines P{C6H3(CF 3)2-3,5}3 and P(C6F 5)3 do not mimic phosphites as ligands for hydroformylation. A comparison of the coordination chemistry of P{C 6H3(CF3)2-3,5}3 and P(C6F5)3
Clarke, Matthew L.,Ellis, Dianne,Mason, Kate L.,Orpen, A. Guy,Pringle, Paul G.,Wingad, Richard L.,Zaher, Damien A.,Baker, R. Tom
, p. 1294 - 1300 (2007/10/03)
The fluoroaryl phosphines P{C6H3(CF3) 2-3,5}3 (La) and P(C6F 5)3 (Lb) form the complexes trans-[MCl 2(La)2] and trans-[MCl2(L b)2] (M = Pd or Pt) which have been isolated and fully characterised. 31P NMR studies of competition experiments show that the stability of trans-[PdCl2L2] is in the order L = Lb a 3. The crystal structure of trans-[PtCl2(La)2] is reported and reveals that the Pt-P bond lengths in trans-[PtCl2L2] are in the order L = Lb a 3. The equilibria established when [Pt(norbornene)3] is treated with La or Lb are investigated by 31P and 195Pt NMR spectroscopy and the species [PtLn(norbornene)3-n] (n = 1-3) identified. Ligands La and Lb appear to have similar affinities for platinum(0). The complexes trans-[MCl(CO)(La) 2] and trans-[MCl(CO)(Lb)2] (M = Rh or Ir) have been synthesised and fully characterised; the values of vco are comparable with those for analogous phosphite complexes. The ligands L a, Lb, P(C6H2F 3-3,4,5)3 (Lc), P{C6H 4(CF3)-2}3 (Ld), PPh3 and P(OPh)3 have been tested in rhodium-catalysed hydroformylation of 1-hexene and La, Lb, and PPh3 have been tested in rhodium-catalysed hydroformylation of 4-methoxystyrene. Ligands L a, and Lb, have been shown to be stable under the hydroformylation catalysis conditions. For the 1-hexene reaction, the activity and selectivity for La and Lc are very similar to the PPh3 catalyst (TOF ca. 400 h-1; n: iso 2.5-3.0) but for the sterically demanding Lb and Ld the activity and selectivity was much lower than with PPh3 (TOF ca. 15, n: iso ratio 0.6). Thus, the yield of heptanals obtained with the catalyst derived from La is 94% while under the same conditions with Lb only 6%. The TOF for the La/Rh catalyst was 5 times lower than for the P(OPh)3/Rh catalyst despite the superficially similar ligand electronic characteristics for La and P(OPh)3. The Royal Society of Chemistry 2005.