ICCAS OpenIR
Heteroscorpionate Rare-Earth Metal Zwitterionic Complexes: Syntheses, Characterization, and Heteroselective Catalysis on the Ring-Opening Polymerization of rac-Lactide
Zhang, Zhichao1,2; Cui, Dongmei1
2011-10-01
Source PublicationCHEMISTRY-A EUROPEAN JOURNAL
ISSN0947-6539
Volume17Issue:41Pages:11520-11526
AbstractNovel neutral phosphine-modified heteroscorpionate ligand (3,5-Me(2)Pz)(2)CHPPh2 (1) and its derivatives oxophosphine (2) and iminophosphine (3) heteroscorpionates were synthesized for the first time. These neutral heteroscorpionate ligands displayed unique chemistry towards rare-earth metal tris(alkyl)s [Ln(CH2SiMe3)(3)(thf)(2)] (Ln=Y, Lu, Sc). The reaction between compound 1 and [Ln-(CH2SiMe3)(3)(thf)(2)] afforded heteroscorpionate rare-earth metal trialkyl adduct complexes 4a-c. Compounds 2 and 3 were treated with [Ln-(CH2SiMe3)(3)(thf)(2)] to give the unprecedented zwitterionic heteroscorpionate rare-earth metal dialkyls 5 and 6, respectively. In the process, the heteroscorpionates transferred to the carbanions by means of methine C-H bond cleavage that was attributed to the presence of the electron-withdrawing groups. In addition the ligand and central metal showed a concerted effect on both the catalytic activity and specific selectivity of complexes 4-6 for the ring-opening polymerization (ROP) of rac-lactide (rac-LA). All the adduct complexes 4 were nonselective and gave atactic polylactide (PLA), probably due to the dissociation of ligand 1 from the active metal center during the polymerization. Strikingly, zwitterionic complexes 5 catalyzed rapid ROP of rac-LA to produce PLAs with heterotacticity up to 0.87. However, the zwitterionic complexes 6 were less active and less selective than 5, which might be on account of the stronger coordination of the tetradentate ligand. Complexes 5 represent rare examples of the selective ROP of rac-LA mediated by rare-earth metal complexes supported by non-bisphenolate ligands.
KeywordC-h Activation Heteroscorpionates Polymerization Rare Earths Zwitterions
DOI10.1002/chem.201102074
Indexed BySCI ; IC
Language英语
WOS IDWOS:000297014400020
PublisherWILEY-V C H VERLAG GMBH
Citation statistics
Cited Times:43[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.iccas.ac.cn/handle/121111/72740
Collection中国科学院化学研究所
Corresponding AuthorCui, Dongmei
Affiliation1.Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Polymer Phys & Chem, Changchun 130022, Peoples R China
2.Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China
Recommended Citation
GB/T 7714
Zhang, Zhichao,Cui, Dongmei. Heteroscorpionate Rare-Earth Metal Zwitterionic Complexes: Syntheses, Characterization, and Heteroselective Catalysis on the Ring-Opening Polymerization of rac-Lactide[J]. CHEMISTRY-A EUROPEAN JOURNAL,2011,17(41):11520-11526.
APA Zhang, Zhichao,&Cui, Dongmei.(2011).Heteroscorpionate Rare-Earth Metal Zwitterionic Complexes: Syntheses, Characterization, and Heteroselective Catalysis on the Ring-Opening Polymerization of rac-Lactide.CHEMISTRY-A EUROPEAN JOURNAL,17(41),11520-11526.
MLA Zhang, Zhichao,et al."Heteroscorpionate Rare-Earth Metal Zwitterionic Complexes: Syntheses, Characterization, and Heteroselective Catalysis on the Ring-Opening Polymerization of rac-Lactide".CHEMISTRY-A EUROPEAN JOURNAL 17.41(2011):11520-11526.
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