Together, these data indicate that THF may dissociate from 1-M in solution to give [M{Si(SiMe3)3}3(THF)n] (n = 0 or 1), which hereafter we respectively refer to as M(THF)0 and M(THF)1. We posit that the loss of coordinated THF and generation of vacant coordination site(s) is the origin of the relatively facile solution decomposition of 1-M, as previously found for [Ln(Si t Bu2R)2(THF)3] (Ln = Sm, Eu, Yb, R = Me; Ln = Sm, Eu, R = t Bu). The Whilst two resonances were seen for SiMe3 groups in both the 13 C{ 1 H} and Si DEPT90 NMR spectra of 1-La and 1-Ce, only resonances associated with group 1 were observed in the corresponding spectra of 1-Pr, 1-Nd and 1-U;