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Synthesis Structure Of The Lanthanide Complexes With Arylamido And Enolate Mixed Ligands And Their Catalytic Behavior For The Disproportionation Reaction Of Aromatic

Posted on:2008-10-12Degree:MasterType:Thesis
Country:ChinaCandidate:W YaoFull Text:PDF
GTID:2121360218957564Subject:Organic Chemistry
Abstract/Summary:PDF Full Text Request
For the first time,our group found that lanthanide amides can initiate the Cannizarro disproportionation reaction of aromatic aldehydes.To further extend the scope of this type Cannizzaro disproportionation reaction and the reactivity of enolate ligand in complex with aldehyde,we designed to synthesis new rare earth complexes containing arylamido and.enolate mixed ligands,studied their reactivity with aromatic aldehydes for the disproportionation reaction.Firstly,two novel rare earth complexes(CH2=CHO)LnⅢ[2,6-(iPr)2PhNSiMe 3]2(μ-Cl)Li(THF)3(Ln=Y(2),Yb(3))containing arylamido and enolate mixed ligands have been synthesized by treatment of 2 equiv of of 2,6-iPr2PhNHSiMe3 with exces n-BuLi at -78℃in THF for 12h,followed by reaction with 1 equiv of LnCl3(Ln =Y,Yb)at 80℃for 24h in one-pot.All the two compounds were characterized by spectroscopic methods,elemental analyses,and a single-crystal X-ray diffraction study.Secondly,we have examined the reactivity of the novel lanthanide complexes with aromatic aldehydes having different substituents.The effects of solvent,temperature and central metal ions of the rare earth complexes on the reactions were studied.The electronic and steric effects of the aromatic aldehydes on the Cannizzaro disproportionation reaction were also examined.Thirdly,in the view of some different results between the reaction of complexes(2),(3)and[(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 with aromatic aldehydes, the reaction of 2 equiv of aromatic aldehydes with 1 equiv of lithium amide(1) catalyzed by the YCl3 was subsequently studied,and better yields of the corresponding amides and alcohols can be isolated.These results indicated that the enolate ligand in complexes(2),(3)may have impact on the Cannizzaro disproportionation reaction.
Keywords/Search Tags:Rare earth complexes, Mixed ligand, Disproportionation, Reaction, Catalysis
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