Lanthanide triflates consist of a lanthanide metal ion and three triflate ions. The lanthanides, or rare earth metals, are the elements from Lanthanum to Lutetium in the periodic table. Triflate is a contraction of trifluoromethanesulfonate; its molecular formula is CF<sub>3</sub>SO<sub>3</sub>, and is commonly designated ‘OTf’. Triflic acid is a ‘superacid’ so its conjugate base ions are very stable. The metal triflate complex is strongly electrophilic, thus acts as a strong Lewis acid.
Lewis acid catalysis
Lewis acids are used to catalyse a wide variety of reactions. The mechanism steps are:
Lewis acid forms a polar coordinate with a basic site on the reactant (such as an O or N)
Its electrons are drawn towards the catalyst, thus activating the reactant