Lanthanide trifluoromethanesulfonates
Lanthanide triflates are
Synthesis
Lanthanide triflates are synthesized from lanthanide oxide and aqueous triflic acid:[2]
- Ln2O3 + 6HOTf + 18H2O → 2[Ln(H2O)9](OTf)3 + 3H2O
Anhydrous lanthanide triflates can be produced by dehydrating their hydrated counterparts by heating between 180 and 200 °C under reduced pressure:[citation needed]
- [Ln(H2O)9](OTf)3 → Ln(OTf)3 + 9H2O
Example reactions
Friedel-Crafts reactions
Lanthanide triflates are proposed for
In contrast, lanthanide triflates' complexes with the product are easily separated by water, and the lanthanide triflate hydrate thus formed can be simply heated to boil the water away (This does not work for aluminium chloride due to loss of HCl; same goes for the lanthanide chlorides, hence the necessity of the triflate counterion). This avoids the need to use organic solvents- one can just use water as the solvent.
Ln(OTf)3 catalysts are used for
Other C-C bond-forming reactions
La(OTf)3 catalysts have been used for
C-N bond-forming reactions
Lanthanide triflates can be used to synthesize pyridine by catalysing either the condensation of aldehydes and amines, or the
Green catalysts
Lanthanide triflates are stable in water, so avoid the need for organic solvents, and can be recovered for reuse.[8] on their catalytic effect in water, the range of researched applications for La(OTf)3 catalysts has exploded.[6] [9] [10]
See also
References
- .
- .
- ^ ISBN 978-0-632-05715-3.
- doi:10.1039/a606484a.
- ^ a b Engberts, J., Feringa, B., Keller, E. & Otto, S. 1996, “Lewis-acid Catalysis of Carbon Carbon Bond Forming Reactions in Water”, Recuil des Travaux Chimiques des Pays-Bas 115(11-12), 457-464
- ^ S2CID 16770637.
- ^ Wenhua Xie; Yafei Jin; Peng George Wang (1999). "Lanthanide triflates as unique Lewis acids". Chemtech. 29 (2): 23–29.
- .
- ^ Shu Kobayashi† and Kei Manabe. Green Lewis acid catalysis in organic synthesis. Pure Appl. Chem., Vol. 72, No. 7, pp. 1373–1380, 2000.
- ^ Waller, F.J.; Barrett. A.G.M.; Braddock, D.C.; Ramprasad, D. "Lanthanide (III) Triflates as Recyclable Catalysts for Atom Economic Aromatic Nitration." Chem. Commun. 1997, 613-614.