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Shen L, Zhai J, Huo Y, Wang X, Shi X. Bis(phosphinophenyl)amido-Ligated Binuclear Rare-Earth Metal Complexes for Highly cis-1,4-Selective Polymerization of 1,3-Conjugated Dienes. Macromol Rapid Commun 2024:e2400486. [PMID: 39141848 DOI: 10.1002/marc.202400486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2024] [Revised: 07/23/2024] [Indexed: 08/16/2024]
Abstract
A series of binuclear rare-earth metal complexes based on the ligands containing bis(phosphinophenyl)amido-PNP unit are successfully synthesized. All the ligands and the corresponding binuclear complexes are fully characterized by NMR spectra (1H, 13C, and 31P). In conjunction with [Ph3C][B(C6F5)4], all the binuclear complexes exhibited high catalytic activity and high cis-1,4-selectivity (>99%) toward the polymerization of 1,3-conjugated dienes (isoprene, β-myrcene and β-farnesene) with excellent livingness at room temperature or even 80 °C.
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Affiliation(s)
- Liying Shen
- College of Chemical Engineering and Materials, Handan University, Handan, 056005, China
| | - Jingjing Zhai
- School of Materials Science and Engineering, Shanghai University, Shanghai, 200444, China
| | - Yanchen Huo
- School of Materials Science and Engineering, Shanghai University, Shanghai, 200444, China
| | - Xiuling Wang
- School of Materials Science and Engineering, Shanghai University, Shanghai, 200444, China
| | - Xiaochao Shi
- School of Materials Science and Engineering, Shanghai University, Shanghai, 200444, China
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2
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Yan X, Chen W, Xie W, Wang X, So YM, Shi X. Binuclear Enamino-Oxazolinate Rare-Earth Metal Complexes: Synthesis and Their Catalytic Performance in Isoprene Polymerization. Inorg Chem 2024; 63:13358-13366. [PMID: 38946308 DOI: 10.1021/acs.inorgchem.4c01219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
We have synthesized a series of binuclear rare-earth metal complexes bearing the newly designed enamino-oxazolinate ligands that feature bridging para-phenyl, meta-phenyl, 1,5-naphthalenyl, and 1,5-anthracenyl moieties. NMR and X-ray diffraction analyses confirmed the binuclear structures of the obtained complexes with two enamino-oxazolinate-metal units located at a trans position against the bridged aryl plane. After activation by [Ph3C][B(C6F5)4], all the rare-earth metal complexes served as efficient catalysts for isoprene polymerization, producing polymers with high cis-1,4 regularity (up to 96.1%) and high molecular weight. The steric and electronic effects exerted on the active metal centers, as well as the radius of metal centers, were the major contributing factors for determining both the catalytic activity and cis-1,4-selectivity of the binuclear catalytic systems. Compared to its mononuclear analogue, the binuclear yttrium catalytic system with a para-phenyl bridge exhibited a higher thermostability and catalytic efficiency during polymerization, revealing a special binuclear effect in this binuclear catalytic system.
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Affiliation(s)
- Xuyang Yan
- Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
| | - Wentao Chen
- Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
| | - Wang Xie
- Research Center for Composite Materials, Shanghai University, Shanghai 200444, China
| | - Xiuling Wang
- Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
| | - Yat-Ming So
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 0000, China
| | - Xiaochao Shi
- Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
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3
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You S, Shi W, Ouyang R, Wang Y, Shi X. Synthesis of bis(oxazoline)-based rare-earth metal complexes and their catalytic performance in the polymerization of isoprene and polar ortho-methoxystyrene. Dalton Trans 2024; 53:10563-10570. [PMID: 38853527 DOI: 10.1039/d4dt01036a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
A series of bis(oxazoline) rare-earth metal dialkyl complexes [(L)Ln(CH2SiMe3)2(THF)n] (L = L1 (dimethyl-substituted bis(oxazoline) ligand), Ln = Y (1-Y), Lu (1-Lu), Sc (1-Sc), n = 1; L = L2 (phenyl-substituted bis(oxazoline) ligand), Ln = Y (2-Y), Lu (2-Lu), Sc (2-Sc), n = 2) was successfully prepared. NMR spectroscopy and X-ray diffraction indicated that all the complexes ligated with a C2 symmetric bis(oxazoline) and two trimethylsilylmethyl ligands. In the presence of borate and triisobutyl aluminium, these complexes exhibited high catalytic activity for the polymerization of isoprene, yielding the polymer with high cis-1,4-regularity (up to 99.9%) and high molecular weight. Moreover, these ternary catalytic systems also served as efficient initiators for the polymerization of polar ortho-methoxystyrene. However, atactic polymers in all the cases were isolated despite the C2 symmetric geometry of bis(oxazoline) ligands.
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Affiliation(s)
- Shuhao You
- Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China.
| | - Wenyu Shi
- Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China.
| | - Ruoxue Ouyang
- Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China.
| | - Yang Wang
- Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China.
| | - Xiaochao Shi
- Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China.
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Lyubov DM, Khristolyubov DO, Cherkasov AV, Trifonov AA. Sc and Y Heteroalkyl and Alkyl-Hydrido Complexes Containing Diphenylmethanide Ligands [2,2′-(4-MeC 6H 3NMe 2) 2CH] −. Organometallics 2023. [DOI: 10.1021/acs.organomet.2c00643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Affiliation(s)
- Dmitry M. Lyubov
- Institute of Organometallic Chemistry of Russian Academy of Sciences, 49 Tropinina str., 603950 Nizhny Novgorod,
GSP-445, Russia
| | - Dmitry O. Khristolyubov
- Institute of Organometallic Chemistry of Russian Academy of Sciences, 49 Tropinina str., 603950 Nizhny Novgorod,
GSP-445, Russia
| | - Anton V. Cherkasov
- Institute of Organometallic Chemistry of Russian Academy of Sciences, 49 Tropinina str., 603950 Nizhny Novgorod,
GSP-445, Russia
| | - Alexander A. Trifonov
- Institute of Organometallic Chemistry of Russian Academy of Sciences, 49 Tropinina str., 603950 Nizhny Novgorod,
GSP-445, Russia
- Institute of Organoelement Compounds of Russian Academy of Sciences, 28 Vavilova str., 119334 Moscow, GSP-1, Russia
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5
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Pan Y, Jiang X, Kang X, Hou X, Wan C, Song X, Leung WH, So YM. Flexible Coordination of the Bis(amino-oxazoline) Ligand in Rare-Earth Metal Complexes: Synthesis, Structure, and Their Reactivity and Polymerization Performance. Inorg Chem 2022; 61:18828-18841. [DOI: 10.1021/acs.inorgchem.2c02057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Yu Pan
- College of Textiles and Clothing, State Key Laboratory of Bio-Fibers and Eco-textiles, Institute of Functional Textiles and Advanced Materials, Qingdao University, Qingdao, Shandong 266071, China
- School of Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Xinxin Jiang
- School of Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Xiaohui Kang
- College of Pharmacy, Dalian Medical University, Dalian, Liaoning 116044, China
| | - Xin Hou
- School of Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Chunteng Wan
- School of Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Xuezhi Song
- School of Chemical Engineering, Dalian University of Technology, Panjin 124221, China
| | - Wa-Hung Leung
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yat-Ming So
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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6
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PNP-Ligated Rare-Earth Metal Catalysts for Efficient Polymerization of Isoprene. Catalysts 2022. [DOI: 10.3390/catal12101131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The tridentate PNP ligand-supported rare-earth metal complexes, i.e., bis[o-diphenylphosphinophenyl]amido-Re-bis[o-dimethylaminobenzyl], [(Ph2P-o-C6H4)2N]Re[(CH2-o-Me2N(C6H4))2]: (Re = Y, 1; Nd, 2; Gd, 3) were applied to isoprene polymerization. When activated with borate activator ([PhMe2NH][B(C6F5)4] (NH-BARF), catalysts 1 and 3 exhibited excellent catalytic efficiency in aromatic media, produced very-high to ultrahigh molecular weight (Mw over 130 × 104 g/moL) polyisoprene rubber (PIR), and the obtained PIR contained over 98% cis-1,4 head-to-tail repeating unites. In most cases, the borate-activated polymerization reaction proceeded in a quasi-living pattern (PDI = 1.2–1.5) under controlled monomer conversion; whereas, activated with the commercially available modified methylaluminoxane (MMAO3A) in aliphatic hydrocarbon media, complexes 1, 2 and 3 all showed high catalytic efficiency, produced high molecular weight PIR with narrow molecular weight distribution (PDI ≤ 2.0) and high cis-1,4 head-to tail repeating unites in the range of 91–95%. Thus, the catalyst systems that consisted of 1, 2 and 3/MMAO3A, are closely relevant to the current industrial polybutadiene rubber (PBR) and PIR production processes.
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Theoretical Study on Ethylene Polymerization Catalyzed by Half-Titanocenes Bearing Different Ancillary Groups. Catalysts 2021. [DOI: 10.3390/catal11111392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Half-titanocenes are well known to show high activity for ethylene polymerization and good capability for copolymerization of ethylene with other olefins, and the ancillary ligands can crucially affect the catalytic performance. In this paper, the mechanisms of ethylene polymerization catalyzed by three half-metallocenes, (η5-C5Me5)TiCl2(O-2,6-iPr2C6H3) (1), (η5-C5Me5)TiCl2(N=CtBu2) (2) and [Me2Si(η5-C5Me4)(NtBu)]TiCl2 (3), have been investigated by density functional theory (DFT) method. At the initiation stage, a higher free energy barrier was determined for complex 1, probably due to the presence of electronegative O atom in phenoxy ligand. At the propagation stage, front-side insertion of the second ethylene is kinetically more favorable than back-side insertion for complexes 1 and 2, while both side insertion orientations are comparable for complex 3. The energy decomposition showed that the bridged cyclopentadienyl amide ligand could enhance the rigidity of the active species as suggested by the lowest deformation energy derived from 3. At the chain termination stage, β-H transfer was calculated to be a dominant chain termination route over β-H elimination, presumably owing to the thermodynamic perspective.
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Side-Arm Assisted Anilido-Imine Based Rare-Earth Metal Complexes for Isoprene Stereoselective Polymerization. Molecules 2021; 26:molecules26144154. [PMID: 34299428 PMCID: PMC8306391 DOI: 10.3390/molecules26144154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/30/2021] [Accepted: 07/06/2021] [Indexed: 11/16/2022] Open
Abstract
Anilido-imine ligands o-C6H4(NHAr1)(CH=NAr2), in which Ar1 is 2,6-diisopropylbenzyl group and Ar2 contains fluorine (HL1) or methoxyl (HL2) group on ortho-position of phenyl substituent, were synthesized for constructing rare-earth metals based complexes of 1a–1c (HL1 based Sc, Lu, Y) and 2a–2c (HL2 based Sc, Lu, Y). Based on their NMR spectra and X-ray single-crystal structures, the side-arm group of -F and -OMe is identified to chelate to the corresponding central metal. The twisted angles between two planes formed by chelated heteroatoms (N, N, F for HL1 and N, N, O for HL2) are observed, in which the largest dihedral angle (53.3°) for HL1-Y and the smallest dihedral angle (44.32°) for HL2-Sc are detected. After being activated by AliBu3 and [Ph3C][B(C6F5)4], these catalysts showed great activity for isoprene polymerization. Bearing the same ligand HL1, smaller scandium based complex 1a and middle size of lutetium based 1b provided lower cis-1,4-selectivity (57.3% and 64.2%), larger yttrium complex 1c displayed high cis-1,4-selectivity (84%). Chelating by crowded HL2, small size of scandium complex 2a provided impressive trans-1,4-selectivity (93.0%), middle lutetium based 2b displayed non-selectivity and larger yttrium complex 2c showed clear cis-1,4-selectivity (83.3%). Moreover, 2a/AliBu3 system showed the quasi-living chain transfer capability.
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9
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Lanthanides and actinides: Annual survey of their organometallic chemistry covering the year 2019. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.213830] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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You F, Zhai J, So YM, Shi X. Rigid Acridane-Based Pincer Supported Rare-Earth Complexes for cis-1,4-Polymerization of 1,3-Conjugated Dienes. Inorg Chem 2021; 60:1797-1805. [PMID: 33444001 DOI: 10.1021/acs.inorgchem.0c03274] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A convenient synthetic route has been developed for preparing the novel rigid 4,5-(PR2)2-2,7,9,9-tetramethylacridane-based pincer ligands (acri-RPNP; R = iPr and Ph), and the first rare-earth (Ln = Y, Lu) alkyl complexes bearing the acri-RPNP ligands were synthesized by a salt metathesis reaction (for the isopropyl-substituent acri-iPrPNP complexes, 1-Ln) or direct alkylation (for the phenyl-substituent acri-PhPNP complexes, 2-Ln). For both 1-Ln and 2-Ln, the NMR spectroscopy and X-ray diffraction study confirmed the successful coordination of the acri-RPNP ligand to the central metal ion in a tridentate manner via the two phosphine and the nitrogen donors. In contrast to 1-Ln that are solvent-free complexes, the metal centers in 2-Ln are each coordinated with one tetrahydrofuran molecule. Upon activation by [Ph3C][B(C6F5)4], 1-Y and 2-Lu could catalyze the living polymerization of isoprene and β-myrcene with high catalytic activity and high cis-1,4-selectivity (up to 92.3% for isoprene and 98.5% for β-myrcene). Moreover, the 1-Y/[Ph3C][B(C6F5)4] catalytic system also could promote the polymerization of butadiene and its copolymerization with isoprene to produce copolymers with high cis-1,4-selectivity and narrow polydispersity.
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Affiliation(s)
- Fen You
- Department of Polymer Materials, College of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China
| | - Jingjing Zhai
- Department of Polymer Materials, College of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China
| | - Yat-Ming So
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xiaochao Shi
- Department of Polymer Materials, College of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China
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11
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Ren W, Liu H, You F, Mao P, So YM, Kang X, Shi X. Unsymmetrical diarylamido-based rare-earth alkyl complexes: their synthesis and catalytic performance in isoprene polymerization. Dalton Trans 2021; 50:1334-1343. [PMID: 33411859 DOI: 10.1039/d0dt04040a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A family of rare-earth complexes bearing diarylamido-based pincer ligands with phosphino-, phenylthio- and quinolino-sidearms have been synthesized and fully characterized. Upon activation by [Ph3C][B(C6F5)4], the scandium (P-Sc and S-Sc) and yttrium complexes (P-Y and S-Y) could catalyze the polymerization of isoprene with cis-1,4 selectivity (up to 98.8%), while the lutetium analogues P-Lu and S-Lu produced trans-1,4 selective polyisoprene (up to 83.3%). Density functional theory (DFT) calculations were carried out to clarify the mechanisms for the metal-dependent stereoselective (cis to trans) polymerization of isoprene catalyzed by P-Sc, P-Y and P-Lu, suggesting that kinetically and thermodynamically more favorable insertion-isomerization during chain propagation is the key reason for P-Lu catalyzed trans-stereoselective isoprene polymerization.
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Affiliation(s)
- Wenhui Ren
- Department of Polymer Materials, College of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China.
| | - Hui Liu
- Department of Polymer Materials, College of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China.
| | - Fen You
- Department of Polymer Materials, College of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China.
| | - Pengjuan Mao
- College of Pharmacy, Institute of Integrative Medicine, Dalian Medical University, Dalian 116044, China.
| | - Yat-Ming So
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xiaohui Kang
- College of Pharmacy, Institute of Integrative Medicine, Dalian Medical University, Dalian 116044, China.
| | - Xiaochao Shi
- Department of Polymer Materials, College of Materials Science and Engineering, Shanghai University, Materials Building, Nanchen Street 333, Shanghai 200444, China.
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12
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Jiang W, Zhang L, Zhang L. Synthesis, Structure, and Reactivity of Monoguanidinate Rare‐Earth Metal Aminobenzyl Enolate Complexes. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Wen Jiang
- Key Laboratory of Functional Molecular Solids Ministry of Education Anhui Laboratory of Molecule‐Based Materials, College of Chemistry and Materials Science Anhui Normal University 241000 Wuhu Anhui China
- Department of Chemistry Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Jiangwan Campus Fudan University 200438 Shanghai China
| | - Li‐Jun Zhang
- Key Laboratory of Functional Molecular Solids Ministry of Education Anhui Laboratory of Molecule‐Based Materials, College of Chemistry and Materials Science Anhui Normal University 241000 Wuhu Anhui China
| | - Li‐Xin Zhang
- Department of Chemistry Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Jiangwan Campus Fudan University 200438 Shanghai China
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13
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Combined ultrafast spectroscopic and TDDFT theoretical studies on dual fluorescence emissions promoted by ligand-to-metal charge transfer (LMCT) excited states of tungsten-containing organometallic complexes. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137396] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Li W, Jiang X, So YM, He G, Pan Y. Lutetium and yttrium complexes supported by an anilido-oxazoline ligand for polymerization of 1,3-conjugated dienes and ε-caprolactone. NEW J CHEM 2020. [DOI: 10.1039/c9nj05081g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lutetium and yttrium complexes supported by an anilido-oxazoline ligand exhibit highcis-1,4 stereoselectivity for 1,3-conjugated diene polymerization and high activity for ring-opening polymerization of ε-caprolactone.
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Affiliation(s)
- Wenqiang Li
- State Key Laboratory of Fine Chemicals
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin 124221
- China
| | - Xinxin Jiang
- State Key Laboratory of Fine Chemicals
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin 124221
- China
| | - Yat-Ming So
- Department of Chemistry
- The Hong Kong University of Science and Technology
- Kowloon
- China
| | - Gaohong He
- State Key Laboratory of Fine Chemicals
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin 124221
- China
| | - Yu Pan
- State Key Laboratory of Fine Chemicals
- School of Petroleum and Chemical Engineering
- Dalian University of Technology
- Panjin 124221
- China
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15
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Song T, Liu N, Tong X, Li F, Mu X, Mu Y. Half-sandwich rare-earth metal complexes bearing a C 5Me 4-C 6H 4-o-CH 2NMe 2 ligand: synthesis, characterization and catalytic properties for isoprene, 1-hexene and MMA polymerization. Dalton Trans 2019; 48:17840-17851. [PMID: 31777884 DOI: 10.1039/c9dt04029c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A new ortho-dimethylaminomethylphenyl-tetramethylcyclopentadienyl ligand C5Me4H-C6H4-o-CH2NMe2 (HL) and a series of rare-earth metal complexes bearing this ligand were synthesized. Of these complexes, two binuclear alkyl complexes [(C5Me4-C6H4-o-CH2N(Me)CH2-μ)Ln(CH2SiMe3)]2 (Ln = Sc (1a) and Y (1b)) were obtained from the alkane elimination reaction of the free ligand with Ln(CH2SiMe3)3(THF)2, followed by an intramolecular C-H activation process of a NMe group in the ligand with a CH2SiMe3 group, two binuclear dichloro complexes (C5Me4-C6H4-o-CH2NMe2)2Y2Cl4[LiCl(THF)2] (2a) and [(C5Me4-C6H4-o-CH2NMe2)LuCl(μ-Cl)]2 (2b) were synthesized by the reaction of anhydrous yttrium or lutetium trichloride with the lithium salt of the ligand LiL, and the binuclear bis(borohydrido) complexes [(C5Me4-C6H4-o-CH2NMe2)Ln(μ-BH4)BH4]2 (Ln = Sm (3a) and Nd (3b)) were synthesized by the reaction of Ln(BH4)3(THF)3 (Ln = Sm and Nd) with the lithium salt of the ligand. The molecular structures of all complexes 1a, 1b, 2a, 2b, 3a and 3b were determined by single-crystal X-ray crystallography. Upon activation with AlR3/Ph3CB(C6F5)4, MAO or MMAO, the binuclear alkyl complexes 1a and 1b show good catalytic activity for isoprene cis-1,4 enriched regioselective polymerization and moderate catalytic activity for 1-hexene polymerization. Complexes 3a and 3b were studied as catalysts for methyl methacrylate polymerization reaction under different conditions and were found to show moderate to high catalytic activity.
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Affiliation(s)
- Tingting Song
- The State Key Laboratory for Supramolecular Structure and Materials, School of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, People's Republic of China.
| | - Ning Liu
- The State Key Laboratory for Supramolecular Structure and Materials, School of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, People's Republic of China.
| | - Xiaobo Tong
- The State Key Laboratory for Supramolecular Structure and Materials, School of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, People's Republic of China.
| | - Feng Li
- The State Key Laboratory for Supramolecular Structure and Materials, School of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, People's Republic of China.
| | - Xiaoyue Mu
- The State Key Laboratory for Supramolecular Structure and Materials, School of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, People's Republic of China.
| | - Ying Mu
- The State Key Laboratory for Supramolecular Structure and Materials, School of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, People's Republic of China.
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16
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Pan Y, Li W, Wei NN, So YM, Lai X, Li Y, Jiang K, He G. Highly active rare-earth metal catalysts for heteroselective ring-opening polymerization of racemic lactide. Dalton Trans 2019; 48:9079-9088. [PMID: 31017172 DOI: 10.1039/c9dt00541b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Rare-earth metal complexes usually exhibit high activities in the ring-opening polymerization (ROP) of lactide, yet only a few scandium complexes have shown satisfactory activity. Herein, we report the synthesis of a series of chiral anilido-oxazoline-supported scandium and yttrium complexes that exhibit high activity in the ROP of racemic lactide (rac-LA). Complexes La-f-Ln(CH2SiMe3)2THF (La-f = 2-(2,6-R2PhN)-phenyl-4-(S)-R'-oxazoline; for 1a-f: L = La-f, Ln = Sc; for 2a-d: L = La-d, Ln = Y) were synthesized via the convenient one-pot reaction of Ln(CH2SiMe3)3(THF)2 (Ln = Sc, Y) with the corresponding proligands. The crystal structures of 1a, 1d, 1e, and 1f were isostructural, adopting a distorted trigonal bipyramidal configuration. Sc complexes 1 showed outstanding activity in the ROP of rac-LA with heteroselectivity. TOFs of up to 720 h-1 and 2910 h-1 were obtained in THF at room temperature and toluene at 60 °C, respectively. To our knowledge, these are the highest activities reported for Sc systems. Y complexes 2 showed higher activity and heteroselectivity than the Sc complexes, with TOFs of up to 1176 h-1 in THF at room temperature. Compared with the ortho-substituent on the anilido moiety, the bulky substituent at the chiral center of the oxazoline ring had a greater effect on controlling the heteroselectivity.
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Affiliation(s)
- Yu Pan
- State Key Laboratory of Fine Chemicals, School of Petroleum and Chemical Engineering, Dalian University of Technology, Panjin 124221, China.
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