Article
Chemistry, Multidisciplinary
Dawei Li, Lichao Ning, Qiliang Luo, Shiyu Wang, Xiaoming Feng, Shunxi Dong
Summary: An array of rare-earth bis(aminobenzyl) complexes supported by imidazolin-2-iminato ligands were synthesized and characterized. These complexes displayed high reactivity towards ortho-Csp(2)-H alkylation of 2-alkylpyridines and benzylic Csp(3)-H alkylation of 2,6-dialkylpyridines with alkenes, providing an atom-economical approach to alkylated pyridine derivatives. Mechanistic investigations revealed the catalytic cycle and enantioselectivity in the asymmetric version of Csp(3)-H alkylation.
SCIENCE CHINA-CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Xiancui Zhu, Dianjun Guo, Fangshi Yao, Zeming Huang, Yang Li, Zuowei Xie, Shaowu Wang
Summary: A series of structurally well-defined cationic rare-earth metal sandwich and half-sandwich complexes were synthesized from the reaction of rare-earth metal trialkyl complexes with pyrrole. Further studies revealed the transformation of these complexes at elevated temperatures, and their catalytic activities in isoprene polymerization were investigated, showing high activities and selectivities.
Article
Chemistry, Inorganic & Nuclear
Fen You, Suting Xu, Jixing Wang, Jingjing Zhai, Fei Wang, Li Pan, Yat-Ming So, Xiaochao Shi
Summary: A simple method for accessing new derivatizable bulky-demanding OHF ligands has been developed, leading to the synthesis of a series of half-sandwich rare-earth metal complexes bearing the OHF ancillary ligands, which exhibit high catalytic activity for styrene (co)polymerization.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Bappaditya Goswami, Manas Khatua, Subhas Samanta
Summary: In this study, four Co(II) complexes were synthesized and characterized using various techniques. Their catalytic activity in styrene polymerization was evaluated, with complex 3 showing the highest efficiency among the azo-aromatic complexes, while the imine-based complex 4 exhibited lower activity.
DALTON TRANSACTIONS
(2022)
Article
Polymer Science
Yuliya A. Piskun, Evgenii A. Ksendzov, Anastasiya V. Resko, Mikhail A. Soldatov, Peter Timashev, Hongzhi Liu, Irina V. Vasilenko, Sergei V. Kostjuk
Summary: The bulk ring-opening polymerization of epsilon-caprolactone was studied using a phosphazene-containing porous polymeric material (HPCP) as the catalyst at high reaction temperatures (130-150 degrees). HPCP, in combination with benzyl alcohol as an initiator, enabled the controlled living ROP of epsilon-caprolactone, producing polyesters with controlled molecular weights up to 6000 g/mol and moderate polydispersity. Higher molecular weight poly(epsilon-caprolactone) was obtained at a lower temperature of 130 degrees C. The HPCP catalyst demonstrated high thermal and chemical stability, allowing for reuse in multiple cycles without significant loss in efficiency. A tentative mechanism involving the activation of the initiator through the basic sites of the catalyst was proposed.
Article
Chemistry, Inorganic & Nuclear
Zhongxian Huang, Aiyuan Li, Jue Chen, Yunjie Luo
Summary: The development of efficient catalysts for copolymerization of nonpolar and polar monomers is a challenging task. The one-pot reaction of anhydrous LnCl3 with pyridyl-methylene-functionalized octamethylfluorenyl lithium OctFlu-CH2PyLi, followed by alkylation, yielded fluorenyl-ligated rare-earth metal bis(alkyl) complexes. These complexes exhibited high syndiotacticity in the polymerization of styrene and para-methoxystyrene, as well as in the syndiospecific copolymerization, with tunable copolymer compositions.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Jiayu Zhang, Wenshuang Huang, Kailing Han, Guoyong Song, Shaowei Hu
Summary: A series of first-row early transition metal dialkyl complexes bearing pincer ligands have been synthesized and their activities in styrene polymerization have been explored.
DALTON TRANSACTIONS
(2022)
Article
Polymer Science
Jiawei Chen, Wenbing Wang, Yao Pan, Dan Peng, Yougui Li, Chen Zou
Summary: In this study, direct copolymerization of plant oil-based copolymer monomers with ethylene was achieved using a dienyl phosphoribosulfonyl palladium catalyst (PO-Pd). Addition, ureido-pyrimidinone (UPy) functionalization was performed using the hydroxyl group of the polymer. The incorporation of biomass groups effectively modifies the surface and mechanical properties of the copolymers, and these newly developed polymers are ideal tougheners for gutter oil due to their excellent tunability of the self-complementary hydrogen bonding network (UPy).
Article
Polymer Science
Harry R. Allcock
Summary: Phosphazene rings and polymer chains have alternating phosphorus and nitrogen atoms with various substituents, including organic and transition metal organometallic side groups. Polymeric organometallic systems are used for catalyst immobilization and the production of electronic and optical materials, with unique physical and engineering properties. Small molecule models are useful for polymer synthesis and structural understanding.
Article
Chemistry, Organic
Yoshifumi Hashikawa, Shumpei Sadai, Yasujiro Murata
Summary: Amino-functionalized cage-opened [60]-fullerene derivatives were synthesized by reactions with phenylenediamine, showing high-lying highest occupied molecular orbital levels and intense near-infrared absorption bands. The reaction involves direct addition of the diamine to the alpha,beta-unsaturated carbonyl moiety and further C-C bond scission promoted by intramolecular S(N)2 reaction.
Article
Polymer Science
Chuang Song, Jupeng Chen, Zhijie Fu, Li Yan, Feng Gao, Qingbin Cao, He Li, Xiangqian Yan, Shilu Chen, Shaowen Zhang, Xiaofang Li
Summary: A scandium dication active species exhibits unprecedentedly high activity and syndiotactic selectivity in the polymerization of o-methoxystyrene, producing syndiotactic poly(oMOS)s with ultrahigh molecular weight not achievable by traditional catalysts.
Article
Chemistry, Multidisciplinary
Yanchen Huo, Xiang Hu, Jixing Wang, Hongfan Hu, Xiaochao Shi
Summary: Amido-trihydroquinoline ligated rare-earth metal complexes have been synthesized and showed moderate catalytic activities for isoprene polymerization. The 2-Y-based catalytic system exhibited excellent control over the polymerization. The alkylaluminium exerted varying influence on the polymerization, and AIMe(3) significantly enhanced the reactivity and 1,4-selectivity. The active yttrium-polyisoprene species were successfully utilized for the polymerization of caprolactone and its copolymerization with isoprene, demonstrating the tunable modification of the copolymer's surface hydrophilicity, with higher content of hydrophilic PCL sequence resulting in lower WAC.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Suting Xu, Jixing Wang, Jingjing Zhai, Fei Wang, Li Pan, Xiaochao Shi
Summary: The study reported the preparation of novel imidazoline-2-imine functionalized fluorenyl ligands with an ethylene bridge and their corresponding rare-earth metal complexes. The rare-earth metal complexes showed high efficiency in promoting the syndiotactic polymerization of ortho-methoxystyrene, achieving a high level of isotacticity. Additionally, the activation effect of the polar groups via sigma-pi chelation of the methoxy and vinyl groups was investigated.
Article
Polymer Science
Kangkang Li, Lei Cui, Yixin Zhang, Zhongbao Jian
Summary: The direct copolymerization of olefins with polar monomers to produce functionalized polyolefins, particularly those with amide functions, has been a challenge. However, by utilizing compounds with high ring strain and an amide moiety in ethylene copolymerization, high amide incorporation, molecular weights, and catalytic activities can be achieved. The resulting amide-functionalized polyethylenes can undergo facile post-transformations to produce polyethylenes with diverse functionalities, such as hydrogen bond-containing, difunctionalized, and water-soluble ammonium-functionalized polyethylenes, which exhibit antibacterial properties.
Article
Chemistry, Inorganic & Nuclear
Cui-Ting Han, Chao Yan, Tie-Qi Xu, Yong-Zheng Zhu
Summary: Rare earth catalysts with tetradentate phenol ether ligands exhibit high isoselectivity for 2-vinylpyridine polymerization, while the influence of ether chain and different types of ligands on the polymerization of 2-VP were also investigated.
Article
Polymer Science
Jianming Huang, Yang Jiang, Zhen Zhang, Shihui Li, Dongmei Cui
MACROMOLECULAR RAPID COMMUNICATIONS
(2020)
Article
Polymer Science
Jian-Ming Huang, Chang-Guang Yao, Shi-Hui Li, Dong-Mei Cui
Summary: The polymerization of 2-(4-halophenyl)-1,3-butadiene and their copolymerization with isoprene using a yttrium catalyst have been studied. The catalyst showed high selectivity for the polymerization of 2-XPB and the insertion ratios of 2-XPB can be tuned. Additionally, quantitative hydrogenation of cis-1,4-poly(2-XPB) resulted in perfect alternating ethylene-halostyrene copolymers.
CHINESE JOURNAL OF POLYMER SCIENCE
(2021)
Article
Materials Science, Ceramics
Lei Su, Xiang-Qun Zhang, Qiao-Yan Dong, Hai-Tao Yang, Shi-Hui Li, Zhao-Hua Cheng
Summary: The influence of Mn doping on TmFeO3 ceramics was studied, showing changes in structure, magnetic properties, and magnetocaloric effect. The transition temperature and magnetic properties were modified with increasing Mn substitution, leading to higher magnetic entropy changes and refrigeration capacities. The study provides valuable information for the potential application and development of RFeO3 materials.
CERAMICS INTERNATIONAL
(2021)
Article
Polymer Science
Zhen Zhang, Yang Jiang, Kai Zhang, Zhong-Yi Cai, Shi-Hui Li, Dong-Mei Cui
Summary: The catalytic performance of rare-earth metal dialkyl complexes in combination with DMAO for styrene polymerization was investigated, with certain complexes showing high catalytic activity and selectivity. Moreover, the system was found to be effective for the polymerization of other styrene derivatives and the copolymerization of ethylene and styrene.
CHINESE JOURNAL OF POLYMER SCIENCE
(2021)
Article
Polymer Science
Yang Jiang, Shihui Li, Dongmei Cui
Summary: The polymerization of ethylvinyl ether (EVE) by rare-earth metal complexes was studied, revealing that metallocenecomplexes exhibited high catalytic activities and produced high molecular weight products under low temperature conditions, while non-metallocene complexes were largely inert in the same conditions.
Article
Chemistry, Multidisciplinary
Yang Jiang, Zhen Zhang, Shihui Li, Dongmei Cui
Summary: This study presents a new method for the isospecific polymerization of unprotected polar styrenes using new racemic ansa-bis(benz[e]indenyl) rare-earth metal complexes. The method demonstrates high activity and perfect isoselectivity for the polymerization without any activators. The insertion rate of polar monomers can be easily adjusted, resulting in isotactic polar polystyrenes with high T(g)s.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Polymer Science
Kai Zhang, Yanli Dou, Yang Jiang, Zhen Zhang, Shihui Li, Dongmei Cui
Summary: The copolymerization of ethylene and butadiene using various scandium complexes led to the successful preparation of high molecular weight and structurally regular E/BD copolymers, showing excellent mechanical and physical properties surpassing traditional rubbers.
Article
Chemistry, Multidisciplinary
Yang Jiang, Zhen Zhang, Shihui Li, Dongmei Cui
Summary: This study explores the coordination polymerization of renewable (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) using various complexes, revealing different activities and regioselectivities. Different complexes are capable of copolymerization and functionalization reactions, showcasing the versatility of this approach in controlling polymer composition and properties.
CHINESE JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Physical
Qiyuan Wang, Zhen Zhang, Yang Jiang, Yanfeng Zhang, Shihui Li, Dongmei Cui
Summary: In this study, a new method for the isospecific polymerization of polar styrenes was reported. By using a sulfur-bridged bis(phenolate) titanium precursor in combination with a coordination activator, crystalline isotactic polymers with high activity and molecular weights were successfully synthesized.
Article
Chemistry, Multidisciplinary
Zhen Zhang, Xiaohui Kang, Yang Jiang, Zhongyi Cai, Shihui Li, Dongmei Cui
Summary: In this study, the method of preparing dis-UHMWPE using binuclear half-sandwich scandium complexes is reported. The complex with a short linker showed higher activity and higher molecular weight compared to the complex with a flexible spacer and the mononuclear complex. The dis-UHMWPE obtained showed very low degree of entanglement under a wide range of temperature and ethylene pressures. These dis-UHMWPEs could be solid-state processed at lower temperatures and exhibited high tensile strength and modulus.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Shihui Li, Ling Cai, Dongmei Cui
Summary: The spontaneous alternating copolymerization of maleic anhydride (MA) and styrene (St) derivatives was investigated using various Lewis acids. With the presence of alkyl aluminum or butyl magnesium, MA-St alternating copolymers with ultra-high molecular weight (M-n <= 166.5x10(4)) and high glass transition temperature (211 degrees C <= T-g <= 216 degrees C) were obtained. The microstructure of the MA-St copolymers was analyzed by H-1 and C-13 NMR spectra. Additionally, the copolymerizations of MA with St derivatives were explored using AlOctyl(3) as an activator in toluene at 50 degrees C.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Polymer Science
Zhen Zhang, Yang Jiang, Rui Lei, Yanfeng Zhang, Shihui Li, Dongmei Cui
Summary: Coordination copolymerization of ethylene with unprotected polar monomers using binuclear half-sandwich scandium complexes C1-Sc-2 and C2-Sc-2 was successfully achieved. The catalysts exhibited significantly higher activities in the copolymerization reactions compared to the mononuclear analogue Sc1. The activities of the catalysts were influenced by the length and nature of the polar olefin monomers.
Article
Polymer Science
Yang Jiang, Zhen Zhang, Hanqing Jiang, Qiyuan Wang, Shihui Li, Dongmei Cui
Summary: This study investigates the copolymerization of ethylene with 6-phenoxy-1-hexene using different sterically hindered scandium precatalysts. Results show that activated precatalyst 1 exhibits high activity (1.4 x 105 g molSc(-1) h(-1)) but low POH incorporation ratio (0.7 mol %), while precatalyst 2 has significantly reduced activity (0.1 x 105 g molSc(-1) h(-1)). Halfsandwich scandium precatalyst 3 shows higher activity (8.1 x 105 g molSc(-1) h(-1)) and produces a copolymer with 7.0 mol % POH. The highest activity (18.0 x 105 g molSc(-1) h(-1)) and incorporation ratio (8.6 mol %) are achieved by precatalyst 4. After optimizing the reaction conditions, up to 16 mol % of POH can be incorporated into the copolymer produced with precatalyst 4.
Article
Microbiology
Jin Zhou, Kai Zou, Shaodong Fu, Zhenchun Duan, Guoqing Zhang, Xinhong Wu, Jingwen Huang, Shihui Li, Xueduan Liu, Shuangfei Zhang, Yili Liang
Summary: This study reported a spherical flavonoid-producing bacteria Deinococcus sp. 43, whose whole genome was sequenced and a series of flavonoid anabolic genes were annotated. The strain was capable of producing flavonoids, and showed potential for industrial production of flavonoids.
Article
Polymer Science
Qi-yuan Wang, Jian-ming Huang, Shi-hui Li, Dong-mei Cui
Summary: By utilizing rare-earth metal catalysts, stereoselective (co)polymerization of IP-OTBS can produce polar group functionalized conjugated diene rubbers, contributing to the enhancement of mechanical properties of green tires.
ACTA POLYMERICA SINICA
(2022)