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Efficient and Heteroselective Heteroscorpionate Rare-Earth-Metal Zwitterionic Initiators for ROP of rac-Lactide: Role of σ-Ligand
A
series of oxophosphine (3,5-Me2Pz)2CHP(R)2O
(Pz = pyrazole; R = tBu (HL1), Cy (HL2))
and iminophosphine (3,5-Me2Pz)2CHP(R)2NAr (R =
Cy, Ar = Ph (HL3); R = Ph, Ar = Ph (HL4), Ar = 2,6-Me2-phenyl
(HL5)) heteroscorpionate ligands were synthesized. Abstraction of
the methide proton of these ligands by rare-earth-metal tris(alkyl)s, Ln(CH2SiMe3)3(THF)2,
afforded the corresponding zwitterionic ...
http://www.polymer.cnt//ss/dongmeicui/publicationsshow_11971.html |
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Ligands Dominate Highly Syndioselective Polymerization of Styrene by Using Constrained-geometry-configuration Rare-earth Metal Precursors
A
series of novel constrained-geometry-configuration (CGC) rare-earth metal
complexes (RCH2–Py)Ln(CH2SiMe3)2(THF)n (Py
= pyridyl; Ln = Y, n = 1, R = C5Me4 (Cp′)
(1); Ln = Y, n = 1, R = C9H6 (Ind)
(2); Ln = Y, n = 1, R = C13H8 (Flu)
(3a); Ln = Lu, n = 1, R = C13H8 (Flu)
(3b); Ln = Sc,n ...
http://www.polymer.cnt//ss/dongmeicui/publicationsshow_11970.html |
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Heteroscorpionate Rare-Earth Metal Zwitterionic Complexes: Syntheses, Characterization, and Heteroselective Catalysis on the Ring-Opening Polymerization of rac-Lactide
Novel neutral phosphine-modified heteroscorpionate ligand (3,5-Me2Pz)2CHPPh2 (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 a...
http://www.polymer.cnt//ss/dongmeicui/publicationsshow_11963.html |
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Synthesis and Reactivity of Rare Earth Metal Alkyl Complexes Stabilized by Anilido Phosphinimine and Amino Phosphine Ligands
Anilido phosphinimino ancillary ligand H2L1 reacted with one equivalent of rare earth metal trialkyl [Ln{CH2Si(CH3)3}3(thf)2] (Ln=Y, Lu) to afford rare earth metal monoalkyl complexes [L1LnCH2Si(CH3)3(THF)] (1?a: Ln=Y; 1?b: Ln=Lu). In this process, deprotonation of H2L1 by one metal alkyl species was followed by intramolecular CH activation of the phenyl group of the phosphine moi...
http://www.polymer.cnt//ss/dongmeicui/publicationsshow_11962.html |
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Copolymerization of Ethylene with 1-Hexene and 1-Octene Catalyzed by Fluorenyl N-Heterocyclic Carbene Ligated Rare-Earth Metal Precursors
Rare-earth metal bis(alkyl) complexes (Flu–NHC)Ln(CH2SiMe3)2 (Ln = Dy (1), Er (2), Sc (3)) attached by fluorenyl-modified N-heterocyclic carbene ligands ((Flu H–NHC–H)Br) have been synthesized by treatment of (FluH–NHC–H)Br with (trimethylsilylmethyl)lithium (LiCH2SiMe3) and rare-earth metal tris(alkyl)s (Ln(CH2SiMe3)3(THF)2) via double-deprotonation reactions in moderate to high yield...
http://www.polymer.cnt//ss/dongmeicui/publicationsshow_11950.html |
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NNN-Tridentate Pyrrolyl Rare-Earth Metal Complexes: Structure and Catalysis on Specific Selective Living Polymerization of Isoprene
The acid–base reactions of NNN-tridentate pyrrolyl ligands (HL1: 2,5-bis((pyrrolidin-1-yl)methylene)-1H-pyrrole; HL2: 2,5-bis((piperidino)methylene)-1H-pyrrole) with rare-earth metal tris(alkyl)s, Ln(CH2SiMe3)3(THF)2, afforded the corresponding bis(alkyl) complexes L1Ln(CH2SiMe3)2(THF)x (Ln = Sc, x = 0 (1a); Ln = Y, x = 1 (1b); Ln = Lu, x = 1 (1c)), L2Sc(CH2Si...
http://www.polymer.cnt//ss/dongmeicui/publicationsshow_11947.html |
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Phosphazene-Functionalized Cyclopentadienyl and Its Derivatives Ligated Rare-Earth Metal Alkyl Complexes: Synthesis, Structures, and Catalysis on Ethylene Polymerization
Treatment of Ln(CH2SiMe3)3(thf)2 (Ln = Sc, Y, and Lu) with 1 equiv of CpPN-type ligands C5H4═PPh2–NH–C6H3R2 (R = Me, L1(Me); R = iPr, L1(iPr)) at room temperature readily generated the corresponding CpPN-type bis(alkyl) complexes 1 and 2a–2c. Addition of 3 equiv of LiCH2SiMe3 to a mixture of L1(iPr) and LnCl3(thf)2 (Ln = Sm and Nd) ...
http://www.polymer.cnt//ss/dongmeicui/publicationsshow_11945.html |
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beta-Diketiminato Rare-Earth Metal Complexes. Structures, Catalysis, and Active Species for Highly cis-1,4-Selective Polymerization of Isoprene
Lithiation of the β-diketimines (2,6-C6H3R2)NH═C(Me)CH═C(Me)N(2,6-C6H3R2) (R = Me (HL1), Et (HL2)) by nBuLi was followed by metathesis reaction with LnCl3(THF)x and Y(BH4)3(THF)2 to afford the corresponding complexes L1LnCl2(THF)2 (Ln = Gd (1), Nd (3), Dy (4), Er (5), Y (6)), L2GdCl2(THF)2 (2), and L1Y(BH4)2(THF) (8), respectively. Treatment of neutral HL1 with Y...
http://www.polymer.cnt//ss/dongmeicui/publicationsshow_11938.html |
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Highly 3,4-Selective Polymerization of Isoprene with NPN Ligand Stabilized Rare-Earth Metal Bis(alkyl)s. Structures and Performances
Deprotonation of Ar(1)NHPPh(2)NAr(2) (H[NPN](n), n = 1 - 10) by Ln(CH(2)SiMe(3))(3)(THF)(2) (Ln = Lu, Y, Sc, Er) generated a series of rare-earth metal bis(alkyl) complexes [NPN](n)Ln(CH(2)SiMe(3))(2)(THF)(2) (1-10), which under activation with [Ph(3)C][B(C(6)F(5))(4)] and AliBu(3) were tested for isoprene polymerization. The correlation between catalytic performances and molecular structures of...
http://www.polymer.cnt//ss/dongmeicui/publicationsshow_11936.html |
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Tridentate CCC-Pincer Bis(carbene)-Ligated Rare-Earth Metal Dibromides. Synthesis and Characterization
The first xylene-bridged bis(N-heterocyclic carbene) (bis(NHC))-ligated CCC-pincer rare-earth metal dibromides (PBNHC)LnBr2(THF) (PBNHC = 2,6-(2,4,6-Me3C6H2NCHCHNCCH2)2C6H3; 1: Ln = Sc; 2: Ln = Lu; 3: Ln = Sm) were prepared by in situ treatment of a THF suspension of 2,6-bis(1-mesitylimidazolium methyl)-1-bromobenzene dibromides ((PBNHC-Br)·2HBr) and lanthanide tr...
http://www.polymer.cnt//ss/dongmeicui/publicationsshow_11930.html |
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