67292-47-1Relevant articles and documents
Novel behaviour and reactivity in 1,1'-bis(diphenylphosphino)ferrocene and 1,1'-bis(diphenylphosphino)cobaltocene cluster derivatives
Shephard, Douglas S.,Johnson, Brian F. G.,Harrison, Andrew,Parsons, Simon,Smidt, Sebastian P.,et al.
, p. 113 - 136 (1998)
The clusters > 2 and > 3 have been synthesised from the reaction of the parent cluster 1 with 1,1'-bis(diphenylphosphino)ferrocene (dppf) in THF.The related compound > 4 is produced from 2 and 3 in more forcing conditions.Both clusters 3 and 4 have been structurally characterised by single crystal X-ray analysis.In 3 the dppf ligand is coordinated in the vicinal form and the cluster core is a highly distorted octahedron.In 4 the vicinal mode is retained but the dppf ligand is coordinated to adjacent basal atoms of a square-base pyramid.The 31P-NMR spectra of 3 and 4 in CD2Cl2 at various temperatures show a high degree of stereochemically non-rigid behaviour.Magnetic susceptibility measurements across a range of temperatures indicate that 3 is paramagnetic at all temperatures.An electrochemical study of 1, 3, 4 and the related > 5 has demonstrated a significant degree of communication between the redox-active sites in 3 and 4.The cluster > 7 has also been synthesised from the direct reaction of the parent cluster 6 with 1,1'-bis(diphenylphosphino)cobaltocene (dppc).Synthesis of the dppc analogue of 3 was attempted but was thwarted by unfavorable redox chemistry.EPR spectra have been obtained for both dppc and 7.The oxidation product of 7 has also been produced (7+) and displays a high degree of stereochemically non-rigid behaviour in a fashion similar to 3 and 4.The magnetic susceptibility of 7 has also been measured, showing an extraordinarily large magnetic moment at ambient temperature. - Keywords: ruthenium clusters; 1,1'-bis(diphenylphosphino)ferrocene; 1,1'-bis(diphenylphosphino)cobaltocene
Ionic phosphine ligands with cobaltocenium backbone: Novel ligands for the highly selective, biphasic, rhodium-catalyzed hydroformylation of 1-octene in ionic liquids
Brasse, Claudia C.,Englert, Ulli,Salzer, Albrecht,Waffenschmidt, Horst,Wasserscheid, Peter
, p. 3818 - 3823 (2008/10/08)
The use of electron-poor phosphine-substituted cobaltocenium salts as ligands for the biphasic hydroformylation in ionic liquids has been investigated. Using improved oxidation methods, 1,1′-bis(diphenylphosphino)cobaltocenium nitrate, 1,1′-bis(diphenylphosphino)cobaltocenium hexafluorophosphate, and 1,1′-bis[1-methyl(1-diphenylphosphino)ethyl]cobaltocenium hexafluorophosphate have been synthesized. 1,1′-Bis(diphenylphosphinocobaltocenium hexafluorophosphate in particular proved to be a very suitable ligand for the biphasic hydroformylation of 1-octene in 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM PF6), enabling high catalyst activity, high selectivity to the n-product, and no detectable catalyst leaching. In contrast to aqueous biphasic systems, the ionic liquid BMIM PF6 provides for the rhodium catalyst a low-coordinating medium with limited but sufficient solubility for 1-octene to allow high reaction rates.
