Syntheses and X-ray structures of cerium amide complexes

Reaction of CeCl3 with an excess of LiTMP (TMP-H = 2,2,6,6-tetramethylpiperidine) gave [Ce(μ-OCHCH2)(TMP)2]2. The alkoxide ligand originated from THF, which was used as the solvent in the reaction. CeCl3 reacted with 3 equiv. of LiTMP in THF to produce, after crystallization, a 3:2 crystalline mixture of Ce(TMP)3 and [Ce(μ-OCHCH2)(TMP)2]2. Ce(TMP)3 could not be isolated cleanly or separated from the mixture except by handpicking the crystals under a microscope. The homoleptic amide complex Ce[N-t-Bu(SiMe3)]3 was obtained by reacting CeCl3(THF)2 with 3 equivalents of LiN-t-Bu(SiMe3). In the solid state, [Ce(μ-OCHCH2)(TMP)2]2 is a dimer with a Ce(μ-OR)2Ce four-member ring, while Ce(TMP)3 and Ce[N-t-Bu(SiMe3)]3 are trigonal planar monomers. There is structural evidence to suggest the presence of a Ce–vinyl group interaction in [Ce(μ-OCHCH2)(TMP)2]2.

The complexes Ce(TMP)3 (TMP-H = 2,2,6,6-tetramethylpiperidine), [Ce(μ-OCHCH2)(TMP)2]2, and Ce[N-t-Bu(SiMe3)]3 were synthesized. The alkoxide ligand in [Ce(μ-OCHCH2)(TMP)2]2 originated from the THF solvent. There is evidence to suggest the presence of a weak Ce–vinyl group interaction in the structure of [Ce(μ-OCHCH2)(TMP)2]2. Ce(TMP)3 and Ce[N-t-Bu(SiMe3)]3 are trigonal planar monomers in the solid state.Figure optionsDownload as PowerPoint slide