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Xue Z, Zhang N, Shi L, Luo G. Origins of Ligand-Controlled Stereoselective Polymerization of ortho-Methoxystyrene by Rare-Earth Catalysts: A Theoretical Perspective. Inorg Chem 2024; 63:9195-9203. [PMID: 38722730 DOI: 10.1021/acs.inorgchem.4c00723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
The stereoselective polymerization of polar vinyl monomers has recently received much attention due to their excellent physicochemical properties. Over the past decade, breakthroughs have been achieved in this field by rare-earth catalysts. However, the mechanistic origins of those stereoselective polymerizations still remain unclear. Herein, stereoselective polymerization of ortho-methoxystyrene (oMOS) by several representative rare-earth catalysts bearing different ligands (i.e., η5-C5Me5, pyridinyl-methylene-fluorenyl, quinolyl-anilido, β-diketiminato) were systematically investigated by density functional theory (DFT) calculations. After achieving agreement between the calculations and experiments, we focused on discussing the role of ligands in controlling stereoselectivity. Our results reveal that the stereoregularity of oMOS polymerization is mainly controlled by the steric effect of the catalyst-monomer structures. Specifically, the type of ligand influences the orientation and configuration of the inserting monomer, thereby affecting the tacticity of the polymers. In the cases of η5-C5Me5-, pyridinyl-methylene-fluorenyl, and quinolyl-anilido-ligated yttrium catalysts, we observe consistent insertion directions and alternating insertion sides of oMOS monomers, leading to syndiotactic selectivity. The opposite insertion directions and the alternating insertion sides of oMOS monomers were observed in the case of the β-diketiminato yttrium catalyst, leading to isotactic selectivity. These findings reported here offer valuable insights into the role of ligands in controlling stereoselectivity in rare-earth catalyzed coordination polymerization of polar vinyl monomers, thus providing guidance for the rational design of new ligands for stereospecific polymerization of polar monomers in the future.
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Affiliation(s)
- Zuqian Xue
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Ni Zhang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Lei Shi
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Gen Luo
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
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Shi L, Zhang N, Xue Z, Luo G. Mechanistic Insights into Rare-Earth-Catalyzed Alternating Copolymerization through C-H Polyaddition of Functionalized Organic Compounds to Unconjugated Dienes. Inorg Chem 2024; 63:8079-8091. [PMID: 38663005 DOI: 10.1021/acs.inorgchem.4c00097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Density functional theory (DFT) calculations have been conducted to elucidate the detailed mechanisms of yttrium-catalyzed C-H polyaddition of 1,4-dimethoxybenzene (DMB) to 1,4-divinylbenzene (DVB). It was computationally determined that DMB not only serves as a substrate but also performs a crucial role as a ligand, stabilizing the catalytically active species and promoting alkene insertion. Side pathways involving Cβ-H activation and C═C continuous insertion were excluded due to steric and electronic factors, respectively, explaining why the reaction occurred efficiently and selectively to give perfectly alternating DMB-DVB polymers. Interestingly, the theoretical prediction of the reactivity of N,N-dimethyl-1,4-phenylenediamine and 2,2'-biethyl-4,4'-bipyridine reveals significant differences in the coordination effects of these substrates, leading to distinct mechanisms, primarily influenced by their steric effects. These findings shed new light on the previously overlooked role of substrate ligand effects in rare-earth-catalyzed step-growth copolymerization reactions.
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Affiliation(s)
- Lei Shi
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Ni Zhang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Zuqian Xue
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Gen Luo
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
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Fu Z, Song C, Chen C, Qi Y, Pei J, Chen Y, Zheng J, Zhao Y, Luo Y, Li X. Polar Molecules Regulating the Regio- and Stereoselectivity of Polymerization of Conjugated Dienes Catalyzed by CGC-Type Rare-Earth Metal Catalysts. Macromol Rapid Commun 2024; 45:e2300653. [PMID: 38261808 DOI: 10.1002/marc.202300653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/06/2024] [Indexed: 01/25/2024]
Abstract
Herein, a concise, effective, and scalable strategy is reported that the introduction of polar molecules (PMs) (e.g., anisole (PhOMe), phenetole (PhOEt), 2-methoxynaphthalene (NaphOMe), thioanisole (PhSMe), and N,N-dimethylaniline (PhNMe2)) as continuously coordinated neutral ligand of cationic active species in situ generated from the constrain-geometry-configuration-type rare-earth metal complexes A-F/AliBu3/[Ph3C][B(C6F5)4] ternary systems can easily switch the regio- and stereoselectivity of the polymerization of conjugated dienes (CDs, including 2-subsituted CDs such as isoprene (IP) and myrcene (MY), 1,2-disubstituted CD ocimene (OC), and 1-substituted polar CD 1-(para-methoxyphenyl)-1,3-butadiene (p-MOPB)) from poor selectivities to high selectivities (for IP and MY: 3,4-selectivity up to 99%; for OC: trans-1,2-selectivity up to 93% (mm up to 90%); for p-MOPB: 3,4-syndioselectivity (3,4- up to 99%, rrrr up to 96%)). DFT calculations explain the continuous coordination roles of PMs on the regulation of the regio- and stereoselectivity of the polymerization of CDs. In comparison with the traditional strategies, this strategy by adding some common PMs is easier and more convenient, decreasing the synthetic cost and complex operation of new metal catalyst and cocatalyst. Such regio- and stereoselective regulation method by using PMs is not reported for the coordination polymerization of olefins catalyzed by rare-earth metal and early transition metal complexes.
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Affiliation(s)
- Zhijie Fu
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Chuang Song
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Chongan Chen
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Yuanxia Qi
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Jingting Pei
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Yuwei Chen
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Jie Zheng
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Yanan Zhao
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Yi Luo
- PetroChina Petrochemical Research Institute, 7 Kunlun Road, Changping District, Beijing, 102206, China
| | - Xiaofang Li
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China
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Li X, Xu T. Stereoselective Polymerization of Aromatic Vinyl Polar Monomers. Eur J Inorg Chem 2023. [DOI: 10.1002/ejic.202200699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Xin‐Lei Li
- State Key Laboratory of Fine Chemicals Department of Chemistry School of Chemical Engineering Dalian University of Technology Dalian 116024 P. R. China
| | - Tie‐Qi Xu
- State Key Laboratory of Fine Chemicals Department of Chemistry School of Chemical Engineering Dalian University of Technology Dalian 116024 P. R. China
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Gao F, Chen J, Cao Q, Li Q, Zheng J, Li X. Three Different Types of Asymmetric Polymerization of Aryl Isocyanides by Using Simple Rare-Earth Metal Trialkyl Precursors. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Feng Gao
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
| | - Jupeng Chen
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
| | - Qingbin Cao
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
| | - Qiaozhen Li
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
| | - Jie Zheng
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
| | - Xiaofang Li
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China
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Isospecific Polymerization of Halide- and Amino-Substituted Styrenes Using a Bis(phenolate) Titanium Catalyst. Catalysts 2022. [DOI: 10.3390/catal12040439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Isospecific polymerization of polar styrenes is a challenge of polymer science. Particularly challenging are monomers bearing electron-withdrawing substituents or bulky substituents. Here, we report the coordination polymerization of halide- and amino-functionalized styrenes including para-fluorostyrene (pFS), para-chlorostyrene (pClS), para-bromostyrene (pBrS), and para-(N,N-diethylamino)styrene (DMAS) using 2,2′-sulfur-bridged bis(phenolate) titanium precursor (1). The combination of 1 and [Ph3C][B(C6F5)4] and AliBu3 provides crystalline poly(pFS)s with perfect isotacticity (mmmm > 95%) and high molecular weights (≤16.0 × 104 g mol−1). Upon activation with a large excess of DMAO, 1 reaches polymerization activity of 5.58 × 105 g molTi−1 h−1 producing isotactic poly(pFS)s featuring higher molecular weights (≤39.6 × 104 g mol−1). The distinguished performance of the 1/DMAO system has been extended to the polymerization of pClS and pBrS, both usually involve halogen abstraction during the polymerization, to produce isotactic and high molecular weight (Mn = 32.2 × 104 vs. 13.7 × 104 g mol−1) polymers in good activities (2.18 × 105 vs. 1.31 × 105 g molTi−1 h−1). Surprisingly, 1/DMAO is nearly inactive for DMAS polymerization, on contrary, the system 1/[Ph3C][B(C6F5)4]/AliBu3 displays isoselectivity (mmmm > 95%) albeit in a moderate activity.
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