Synthesis and reactivity of a β-diketiminate Sm

Abstract

Attempts to stabilise a TmII metal centre with the bulky β-diketiminate ligand HC[C(Me)=N(DIPP)]2 (BDI) failed (DIPP, 2,6-diisopropylphenyl). Reaction of TmI2 and 2 equiv. (BDI)K gave the TmIII complex (BDI)(BDI-H)Tm (1) in which (BDI-H)2− is a doubly deprotonated ligand. However, following the same route, (BDI)2Sm (2) was isolated in 48% crystalline yield. Complex 2 is highly soluble in aromatic solvents or alkanes and was reacted with various reagents like phenazine, PhSSPh, O2, NO, cuminil and fluorenone. This led to isolation and structural characterisation of the following SmIII complexes: [(BDI)2Sm]2(μ-phenazine) (3), [(BDI)Sm(SPh)(μ-SPh)]2 (4), (BDI)(BDI-H)Sm (5a), (BDI)2Sm(OC13H8) (6) and (BDI)2Sm(NO2) (7). The rich redox reactivity of (BDI)2Sm (2) and its very high solubility in apolar solvents like hexane make it an attractive reducing agent in synthesis.