Heterometallic Rare-Earth Metal Complexes With Imino-Functionalized 8-Hydroxyquinolyl Ligands: Synthesis, Characterization And Catalytic Activity Towards Hydrophosphinylation Of Trans-Beta-Nitroalkene

Reactions of rare-earth metal amides [(Me3Si)(2)N](3)RE(mu-Cl)Li(THF)(3) with different equiv. of 2-(2,6-diisopropylphenylimino)-8-hydroxyquinoline (1) afforded different heterometallic rare-earth metal complexes, and catalytic activity of the resulting complexes was investigated. Reactions of rare-earth metal amides [(Me3Si)(2)N](3)RE(mu-Cl)Li(THF)(3) (RE = Y, Er, Dy) with 1 equiv. of compound 1 afforded the heterobimetallic rare-earth metal and lithium complexes 2-4 bridged by the oxygen atom of 2-(2,6-diisopropylphenylimino)-8-hydroxyquinoline and the nitrogen atom of N(SiMe3)(2). However, the treatment of rare-earth metal amides [(Me3Si)(2)N](3)RE(mu-Cl)Li(THF)(3) (RE = Sm, Er, Yb) with 2 equiv. of compound 1 gave different heterobimetallic rare-earth metal and lithium complexes 5-7 bridged by the oxygen atoms of 2-(2,6-diisopropylphenylimino)-8-hydroxyquinoline. Complex 6 can also be prepared by the treatment of 3 with 1 equiv. of 1. Complexes 2-7 were fully characterized using spectroscopic methods, elemental analyses and single crystal X-ray diffraction. Investigation of the catalytic properties of the complexes indicated that all complexes exhibited a high catalytic activity towards the addition of diphenylphosphine oxide to trans-beta-nitroalkenes to afford beta-nitrophosphonates under mild conditions.