For 1-Ce two shoulders were seen at ῦmax = 22,000 cm -1 (ε = 750 M -1 cm -1 ) and 19,500 cm -1 (ε = 180 M -1 cm -1 ); the lower energy absorption may be due to a 4f 1 →5d 1 transition, as assigned previously for [Ce{Si(SiMe3)3}3(THF)2] (ῦmax = 23,300 cm -1 , ε = 240 M -1 cm -1 ). The electronic spectrum of 1-Nd has a weak absorption at ῦmax = 18,650 cm -1 (ε = 50 M -1 cm - . For 1-Sm, there is a broad and relatively intense absorption in the visible region (ῦmax = 17,800 cm -1 ; ε = 500 M -1 cm -1 ). This is unusual as Sm(III) complexes typically only show weak f-f transitions in this region. However, we have noted previously that the CT band tends to tail in further into the visible region for Sm(III) homologues of a structurally analogous series of light Ln(III) complexes, and that more axial ligand fields can effect a greater blue-shift for the CT bands of similar Sm(III) complexes. We therefore assign this feature to a ligand metal charge transfer (LMCT) that arises due to significant orbital mixing of the 4f and 5d orbitals and vibronic coupling occurring in 1-Sm. A similar strong absorbance has been observed in the spectrum of [Eu(N′′)3] at approximately 16,000 cm -1 , which was ascribed to a LMCT. 31