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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.cn//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.cn//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.cn//ss/dongmeicui/publicationsshow_11930.html |
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Synthesis of the first rare earth metal bis(alkyl)s bearing an indenyl functionalized N-heterocyclic carbene
Treatment of indenyl-modified imidazolium bromide [C9H7CH2CH2(NCHCHN(C6H2Me3-2,4,6)CH)Br] ((IndH-NHC-H)Br) with rare earth metal tetra(alkyl) lithium (Ln(CH2SiMe3)4Li(THF)4) or with (trimethylsilylmethyl)lithium (LiCH2SiMe3) and rare earth metal tris(alkyl)s (Ln(CH2SiMe3)3(THF)2) sequentially afforded the first NHC-stabilized monomeric rare earth metal bis(alkyl) complexes (Ind-NHC)Ln(CH2SiMe3)2...
http://www.polymer.cn//ss/dongmeicui/publicationsshow_11926.html |
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3,4-Polymerization of Isoprene by Using NSN- and NPN-Ligated Rare Earth Metal Precursors: Switching of Stereo Selectivity and Mechanism
The rare-earth metal complexes bearing NSN-bidentate β-diimidosulfonate ligands (RNSNdipp)Ln(CH2SiMe3)2(THF)n (R = Ph, Ln = Lu (1a), n = 1, Y (1b), n = 2, Sc (1c), n = 1; R = PhNMe2, Ln = Lu (1d), n = 1) were synthesized by treatment of the ion-pairs [Ln(CH2SiMe3)2(THF)x][BPh4] with equimolar amount of the ligand lithium salts (RNSNdipp)Li(THF)2 ...
http://www.polymer.cn//ss/dongmeicui/publicationsshow_11919.html |
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Highly 3,4-selective living polymerization of isoprene with rare earth metal fluorenyl N-heterocyclic carbene precursors
Fluorenyl modified N-heterocyclic carbene ligated rare earth metal bis(alkyl) complexes, (Flu-NHC)Ln(CH2SiMe3)2 (Flu-NHC = (C13H8CH2CH2(NCHCCHN)C6H2Me3-2,4,6); Ln = Sc (1a); Ln = Y (1b); Ln = Ho (1c); Ln = Lu (1d)), were synthesized and fully characterized by NMR and X-ray diffraction analyses. Complexes 1b?d with the activation of AliBu3 and [Ph3C][B(C6F5)4] exhibited high a...
http://www.polymer.cn//ss/dongmeicui/publicationsshow_11915.html |
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24. Synthesis of siloxane-modified melamine-formaldehyde microsphere and its heavy metal ions adsorption by coordination effects
Microspheres could be utilized in the industrial waste water treatment due to their huge specific surface areas and surficial functional groups, which possibly adsorb heavy metal ions in the industrial waste. Melamine-formaldehyde (MF) microspheres were easily prepared as mono-dispersed micro-sized particles with a smooth surface. However, these rich amine groups in MF m...
http://www.polymer.cn//ss/ghgao/publicationsshow_11905.html |
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ansa-Rare-Earth-Metal Catalysts for Rapid and Stereoselective Polymerization of Renewable Methylene Methylbutyrolactones
Two ansa-half-sandwich rare-earth-metal (REM) dialkyl complexes supported by an ethylene-bridged fluorenyl (Flu)-N-heterocyclic carbene (NHC) ligand, [M{C2H4(η5-Flu-κ1-NHC)}(CH2SiMe3)2] (M=Y, 1; Lu, 2), and a chiral ansa-sandwich samarocene incorporating a C2 ligand, [Sm(η5-C12H8)2(thf)2] (3), have been investigated for the coordination–addition polymerization o...
http://www.polymer.cn//ss/dongmeicui/publicationsshow_11895.html |
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Isoprene polymerization with aminopyridinato ligand supported rare-earth metal complexes. Switching of the regio- and stereoselectivity
The highly cis-1,4, trans-1,4 and 3,4-selective polymerizations of isoprene were successfully regulated by simply modifying the auxiliary ligands, metal centres and initiation groups of rare-earth metal complexes and cocatalysts.
http://www.polymer.cn//ss/dongmeicui/publicationsshow_11887.html |
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Nature of the Entire Range of Rare Earth Metal-Based Cationic Catalysts for Highly Active and Syndioselective Styrene Polymerization
Because of the steric bulkiness and the eta(5)/kappa(1)-constrained-geometry-configuration (CGC) geometry, the entire range of pyridyl-methylene-fluorenyl-stabilized rare earth metal bisalkyl complexes, (Flu-CH2-Py)Ln(CH2SiMe3)(2)(THF)(x) (Flu = fluorenyl; Py = pyridyl; for 1, Ln = Sc and x = 0; for 2-11, Ln = Lu, Tm, Er, Ho, Y, Dy, Tb, Gd, Nd, or Pr and x = 1), and monoalkyl complex, (Flu-CH2-P...
http://www.polymer.cn//ss/dongmeicui/publicationsshow_11886.html |
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