Migration of amide to imine group of lanthanide Schiff base complexes: effect of amido group.
The protonolysis of anionic lanthanide amide complexes (THF)LiLn(NPri2)4 with two equiv. of tridentate Schiff base HL (L=3,5-But(2)-2-O-C6H2CH=N-C5H4N) afforded the unanticipated products LiL'2Ln(THF) (L'=3,5-But(2)-2-O-C6H2CH(NPri2)-N-C5H4N; Ln=Y 1, Sm 2 and Yb 3) formed by intramolecular nucleophilic attack of the amide groups at the imine carbon atoms of the original ligand, L. The protonolysis is greatly affected by the amide group. When amine elimination was carried out with a mixture of Ln[N(TMS)2]3(micro-Cl)Li(THF)3 (TMS=SiMe3) and LiN(TMS)2, the expected lanthanide amide complexes with two Schiff base ligands, L2Ln[N(TMS)2] (Ln=Sm 4 and Nd 5), were isolated and no migration of the N(TMS)2 group was observed because of steric hindrance. Complexes 1-5 were well characterized including X-ray structural analyses.
Qin
Duwei
D
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus, Suzhou University, Suzhou, 215123, People's Republic of China.
Han
Fubin
F
Yao
Yingming
Y
Zhang
Yong
Y
Shen
Qi
Q