Strategic Design and Refinement of Lewis Acid–Base Catalysis by Rare-Earth-Metal-Containing Polyoxometalates

2012 ◽  
Vol 51 (12) ◽  
pp. 6953-6961 ◽  
Author(s):  
Kosuke Suzuki ◽  
Midori Sugawa ◽  
Yuji Kikukawa ◽  
Keigo Kamata ◽  
Kazuya Yamaguchi ◽  
...  
Keyword(s):  
Rare Earth ◽  
Lewis Acid ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Base Catalysis ◽  
Acid Base ◽  
Strategic Design

Rare-earth metal bis(aminobenzyl) complexes supported by pyrrolyl-functionalized arylamide ligands: synthesis, characterization and styrene polymerization performance

2018 ◽  
Vol 47 (29) ◽  
pp. 9709-9716 ◽  
Author(s):  
Min Li ◽  
Chaopan Wang ◽  
Hongzhen Xie ◽  
Zehuai Mou ◽  
Yunjie Luo
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Molar Ratio ◽  
Acid Base ◽  
Styrene Polymerization ◽  
Catalyst Systems

Acid–base reaction between Ln(CH2C6H4NMe2-o)3 and 2,5-Me2C4H2NCH2SiMe2NHC6H4R (R = H, (HL1); R = Cl-p, (HL2) in 1 : 1 molar ratio gave L1Ln(CH2C6H4NMe2-o)2 (Ln = Sc (1), La (2), Lu (3) and L2Ln(CH2C6H4NMe2-o)2 (Ln = Sc (4), La (5), Lu (6). The catalyst systems of 2 or 5/[Ph3C][B(C6F5)4] were active for syndio-specific styrene polymerization.

Catalytic Asymmetric Ring-Opening ofmeso-Aziridines with Malonates under Heterodinuclear Rare Earth Metal Schiff Base Catalysis

2011 ◽  
Vol 133 (15) ◽  
pp. 5791-5793 ◽  
Author(s):  
Yingjie Xu ◽  
Luqing Lin ◽  
Motomu Kanai ◽  
Shigeki Matsunaga ◽  
Masakatsu Shibasaki
Keyword(s):  
Schiff Base ◽  
Rare Earth ◽  
Rare Earth Metal ◽  
Ring Opening ◽  
Earth Metal ◽  
Base Catalysis ◽  
Catalytic Asymmetric ◽  
Asymmetric Ring Opening

scholarly journals Cis-1,4-Polymerization of Isoprene by 1,3-Bis(oxazolinymethylidene)isoindoline Ligated Rare Earth Metal Dialkyl Complexes

2017 ◽  
Author(s):  
Chao Yu ◽  
Dahai Zhou ◽  
Xiangqian Yan ◽  
Fei Gao ◽  
Li Zhang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Acid Base ◽  
X Ray ◽  
Molecular Weights ◽  
Molecular Weight Distributions ◽  
Trigonal Bipyramidal ◽  
Weight Distributions ◽  
Distorted Trigonal Bipyramidal

A series of novel chiral nonmetallocene pincer-type rare earth metal dialkyl complexes bearing the chiral monoanionic tridentate C2-symmetric 1,3-bis(oxazolinymethylidene)isoindoline (BOXMI) ligand (BOXMI)Ln(CH2SiMe3)2 1-3 (1, Ln = Sc, yield = 57%; 2, Ln = Lu, yield = 55%; 3, Ln = Y, yield = 62%) have been prepared in moderate yields via the acid-base reaction between the BOXMI ligand and rare earth metal tri(trimethylsilylmethyl) complexes. The X-ray diffractions show that both of the complexes 1 and 2 contain one Boxmi ligand and two trimethylsilylmethyl ligands, adopting a distorted-trigonal-bipyramidal configuration. In the presence of cocatalyst such as borate and AlR3, these complexes 1-3 exhibit high activities up to 6.8 × 104 (g of polymer)/(molLn h) and high cis-1,4-selectivities up to 97%) in the polymerization of isoprene in toluene, yielding the cis-1,4-polyisoprenes with high molecular weights (Mn up to 710000 g/mol) and bimodal molecular weight distributions (Mw/Mn = 2.0-4.5).

Polymerization and Chiroptical Behavior of Polymethacrylamides Bearing a Bulky Oxazoline Pendant

2014 ◽  
Vol 887-888 ◽  
pp. 688-692
Author(s):  
Zheng Fu ◽  
Hong Wei ◽  
Chao Yuan ◽  
Zhong Wen Li
Keyword(s):  
Rare Earth ◽  
Free Radical ◽  
Radical Polymerization ◽  
Lewis Acid ◽  
Rare Earth Metal ◽  
Lewis Acids ◽  
Earth Metal ◽  
Free Radical Polymerization ◽  
Optically Active ◽  
Circular Dichroïsm

The radical polymerization of optically active methacrylamide derivatives, N-[o-(4-phenyl-4,5-dihydro-1,3-oxazol-2-yl) phenymethacrylamide ((R)-PhOPMAM) and N-[o-(4-isopropyl-4,5-dihydro-1,3-oxazol-2-yl) phenymethacrylamide ((S)-PriOPMAM), were carried out under various conditions. The effect of the Lewis acid, that is, rare earth metal trifluoromethanesulfonates on the free-radical polymerization were examined under different solvents. The Lewis acids are effective in enhancing the isotacticity in the polymerization of (S)-PriOPMAM. The same phenomenon were not happened in the polymerization of (R)-PhOPMAM. The polymerization characteristics and the chiroptical behavior of the resultant polymers have been examined by using circular dichroism (CD), UVVis, and NMR spectroscopies.

Polymerization and Chiroptical Behavior of N-[o-(4-isopropyl-4,5-dihydro-1,3-oxazol-2-yl) phenyl] Methacrylamide

2013 ◽  
Vol 477-478 ◽  
pp. 1187-1191 ◽  
Author(s):  
Zheng Fu ◽  
Hong Wei ◽  
Yang Ding ◽  
Chao Yuan
Keyword(s):  
Rare Earth ◽  
Circular Dichroism ◽  
Free Radical ◽  
Radical Polymerization ◽  
Lewis Acid ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Free Radical Polymerization ◽  
Optically Active ◽  
Circular Dichroïsm

The radical polymerization of optically active methacrylamide derivative, N-[o-(4-isopropyl-4,5-dihydro -1,3-oxazol-2-yl)phenyl] methacrylamide ((S)-MeOPMAM), was carried out under various conditions. The effect of Lewis acid, that is, rare earth metal trifluoromethanesulfonates on the free-radical polymerization were examined under different solvents. The polymerization in the presence of rare earth metal trifluoromethanesulfonates produced isotactic-rich polymers compared with those obtained without the Lewis acid. The polymerization characteristics and the chiroptical behavior of the resultant polymers have been examined by using circular dichroism (CD), UV–Vis, and NMR spectroscopies.

scholarly journals An efficient synthesis of procyanidins. Rare earth metal Lewis acid catalyzed equimolar condensation of catechin and epicatechin

2007 ◽  
Vol 48 (33) ◽  
pp. 5891-5894 ◽  
Author(s):  
Yoshihiro Mohri ◽  
Masayoshi Sagehashi ◽  
Taiji Yamada ◽  
Yasunao Hattori ◽  
Keiji Morimura ◽  
...  
Keyword(s):  
Rare Earth ◽  
Lewis Acid ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Efficient Synthesis ◽  
Acid Catalyzed

scholarly journals An Efficient Synthesis of Procyanidins. Rare Earth Metal Lewis Acid Catalyzed Equimolar Condensation of Catechin and Epicatechin.

ChemInform ◽  
2007 ◽  
Vol 38 (48) ◽  
Author(s):  
Yoshihiro Mohri ◽  
Masayoshi Sagehashi ◽  
Taiji Yamada ◽  
Yasunao Hattori ◽  
Keiji Morimura ◽  
...  
Keyword(s):  
Rare Earth ◽  
Lewis Acid ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Efficient Synthesis ◽  
Acid Catalyzed
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