Diamine bis(phenolate) samarium complexes: Synthesis and structures

Samarium complexes supported by the diamine bis(phenol) proligand H2(tBu2O2NN′) = Me2N(CH2)2N{CH2-(2-OH-3,5-tBu2-C6H2)2} were prepared and structurally characterized. [Sm(tBu2O2NN′)]2(μ-Cl)2 (1) was obtained from reaction of SmCl3 with K2(tBu2O2NN′) in THF, DME or pyridine. The reaction of 1 with LiNEt2 gave a zwitterionic bimetallic complex of Sm and Li, [Sm(tBu2O2NN′)2Li] (2) that formed upon ligand redistribution and did not allow the isolation of the expected diethylamido derivative. Analogously treatment of Sm{N(SiMe3)2}3 with H2tBu2O2NN′ led to a zwitterionic samarium complex [Sm(tBu2O2NN′)(tBu2O2N(H)N′)] (3) that also displays a 2ligand:1Sm ratio. In 3 the samarium is formally an ate centre and the tripodal nitrogen of one of the ligands is protonated. The reaction of 1 with Li[2-(CH2NMe2)C6H4] proceeded through chloride metathesis to give [Sm(tBu2O2NN′)(κ2-{2-(CH2NMe2)-C6H4})] (4).