18475-06-4Relevant articles and documents
Effect of fluorine and trifluoromethyl substitution on the donor properties and stereodynamical behaviour of triarylphosphines
Howell, James A. S.,Fey, Natalie,Lovatt, Jonathan D.,Yates, Paul C.,McArdle, Patrick,Cunningham, Desmond,Sadeh, Einat,Gottlieb, Hugo E.,Goldschmidt, Zeev,Hursthouse, Michael B.,Light, Mark E.
, p. 3015 - 3028 (2007/10/03)
A series of 2-, 3- or 4-trifluoromethyl substituted triarylphosphines and their oxide, chalcogenide and Fe(CO)4 derivatives have been prepared and characterised spectroscopically and crystallographically. Electronic effects of CF3 su
Reactivity of Fe(CO)4(H)MPh3 (M = Si, Ge) and mechanism of substitution by two-electron-donor ligands: Implications for the mechanism of hydrosilylation of olefins catalyzed by Fe(CO)5
Bellachioma, Gianfranco,Cardaci, Giuseppe,Colomer, Ernest,Corriu, Robert J. P.,Vioux, André
, p. 519 - 525 (2008/10/08)
cis-Fe(CO)4(H)MPh3 (M = Si, Ge) complexes undergo carbonyl displacement with nucleophilic ligands (phosphines, phosphites) to give Fe(CO)3(H)(L)MPh3. With M = Si the geometry of these complexes depends on the nature of the solvent; in nucleophilic solvents the mer-OC-6-43 isomer is formed, while in nonnucleophilic solvents the mer-OC-6-23 isomer is obtained (the cis positions of H and Si are retained). These two isomers undergo concerted reductive elimination of silane with PPh3. The mer-OC-6-43 isomer reacts 183 ± 19 times faster than the mer-OC-6-23 isomer in toluene at 26.0°C, giving the same 16-electron intermediate; the calculated equilibrium constant for the interconversion of OC-6-43 and OC-6-23 is 823 ± 192 at 26.0°C in toluene. Owing to the strong acidity of Fe(CO)4(H)MPh3 (pKa estimated as 3CN) and of Fe(CO)3(H)(PPh3)MPh3 (pKa estimated as ≤8.94 in CH3CN), reaction with basic two-electron-donor ligands [P(alkyl)3, P(cycloalkyl)3, NR3] leads to the formation of the anionic trigonal-bipyramidal complexes [Fe(CO)4MPh3]- and [Fe(CO)3(L)MPh3]-. cis-Fe(CO)4(H)SiPh3 reacts with isoprene to give [Fe(CO)4SiPh3]2; this reaction is not observed with Fe(CO)3(H)(L)SiPh3. The versatile reactivity of these complexes sheds some light on the mechanism of hydrosilylation of olefins and conjugated dienes. Under thermal conditions previous coordination of the olefin to the metal in this reaction seems to be excluded.
Low temperature photochemistry of . Stabilization of an intermediate photoproduct in a decomposition reaction
Dijk, Hans K. van,Stufkens, Derk J.,Oskam, Ad
, p. 227 - 238 (2007/10/02)
The complex (I), a photoproduct from , is itself photolabile.The UV, IR, resonance Raman spectra of I are described and used for the interpretation of its photochemical behaviour.Irradiation of I in its low-energy MLCT band in the presence of PR3 or a N-donor ligand (L) causes photosubstitution of the last CO ligand of the Fe(1)-bipy moiety, giving the thermally unstable complex (II).Because of this thermal lability of the primary photoproduct, the photochemical reactions were performed in 2-Me-THF at 133 K.The complexes II with L=PR3 decomposed thermally above 200 K, but when L was an N-donor ligand, partial decomposition took place at 133 K.The nature of these decomposition products depend on L.It is suggested that the photochemical reactions occur from a reactive 3LF state after intersystem crossing from the 1MLCT state.Evidence for a close lying 1LF state comes from the resonance Raman spectrum upon 458 nm excitation, which shows anti-resonance Raman effects for all the vibrations.
