First identification by EPR spectra of lanthanum(ii) organometallic intermediates (and E½ for La3+ → La2+) in the C–O bond activation of dimethoxyethane

Abstract

The reaction of [La(Cp″) ₃ ] with K in dimethoxyethane (dme) at ambient temperature leads to the formation of lanthanocene(III) methoxides via persistent paramagnetic lanthanum(II) intermediates that are characterised by EPR spectroscopy and tentatively assigned to [K(dme) _x ]- [La(Cp″) ₃ ] and [La(Cp″) ₂ (dme) _y ] [Cp″ = η ⁵ -C ₅ H ₃ (SiMe ₃ ) ₂ -1,3]; the cyclic voltammogram of [La(Cp″) ₃ ] in thf is also reported, E ^red _½ = -2.8 V.