Synthesis, Characterization, and Catalytic Behaviors in Isoprene Polymerization of Pyridine–Oxazoline-Ligated Cobalt Complexes
A family of pyridine–oxazoline-ligated cobalt complexes L<sub>2</sub>CoCl<sub>2</sub> <b>3a</b>–<b>h</b> were synthesized and characterized. Determined via single-crystal X-ray diffraction, complexes <b>3a</b> and <b>3d,</b> lig...
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2024-02-01
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| author | Xiuge Hao Jin-Kui Liu Weize Zhuo Jiajing Zheng Xin-Qi Hao Jun-Fang Gong Hui Jiang Mao-Ping Song |
| author_facet | Xiuge Hao Jin-Kui Liu Weize Zhuo Jiajing Zheng Xin-Qi Hao Jun-Fang Gong Hui Jiang Mao-Ping Song |
| author_sort | Xiuge Hao |
| collection | DOAJ |
| description | A family of pyridine–oxazoline-ligated cobalt complexes L<sub>2</sub>CoCl<sub>2</sub> <b>3a</b>–<b>h</b> were synthesized and characterized. Determined via single-crystal X-ray diffraction, complexes <b>3a</b> and <b>3d,</b> ligated by two ligands, displayed a distorted tetrahedral coordination of a cobalt center. The X-ray structure indicated the pyridine–oxazoline ligands acted as unusual mono-dentate ligands by coordinating only to N<sub>oxazoline</sub>. Upon activation with AlEt<sub>2</sub>Cl (diethylaluminum chloride), these cobalt complexes all exhibited high catalytic activity (up to 2.5 × 10<sup>6</sup> g·mol<sub>Co</sub><sup>−1</sup>·h<sup>−1</sup>), affording <i>cis</i>-1,4-<i>co</i>-3,4-polyisoprene with molecular weights of 4.4–176 kg mol<sup>−1</sup> and a narrow Ð of 1.79–3.42, suggesting a single-site nature of the active sites. The structure of cobalt catalysts and reaction parameters, especially co-catalysts and the reaction temperature, all have significant influence on the polymerization activity but not on the microstructure of polyisoprene. |
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| last_indexed | 2024-04-25T00:21:18Z |
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| spelling | doaj.art-989dd1d1d3514e3897d7794801c1b1622024-03-12T16:53:18ZengMDPI AGPolymers2073-43602024-02-0116557810.3390/polym16050578Synthesis, Characterization, and Catalytic Behaviors in Isoprene Polymerization of Pyridine–Oxazoline-Ligated Cobalt ComplexesXiuge Hao0Jin-Kui Liu1Weize Zhuo2Jiajing Zheng3Xin-Qi Hao4Jun-Fang Gong5Hui Jiang6Mao-Ping Song7College of Chemistry, Zhengzhou University, Zhengzhou 450001, ChinaCollege of Chemistry, Zhengzhou University, Zhengzhou 450001, ChinaCollege of Chemistry, Zhengzhou University, Zhengzhou 450001, ChinaCollege of Chemistry, Zhengzhou University, Zhengzhou 450001, ChinaCollege of Chemistry, Zhengzhou University, Zhengzhou 450001, ChinaCollege of Chemistry, Zhengzhou University, Zhengzhou 450001, ChinaCollege of Chemistry, Zhengzhou University, Zhengzhou 450001, ChinaCollege of Chemistry, Zhengzhou University, Zhengzhou 450001, ChinaA family of pyridine–oxazoline-ligated cobalt complexes L<sub>2</sub>CoCl<sub>2</sub> <b>3a</b>–<b>h</b> were synthesized and characterized. Determined via single-crystal X-ray diffraction, complexes <b>3a</b> and <b>3d,</b> ligated by two ligands, displayed a distorted tetrahedral coordination of a cobalt center. The X-ray structure indicated the pyridine–oxazoline ligands acted as unusual mono-dentate ligands by coordinating only to N<sub>oxazoline</sub>. Upon activation with AlEt<sub>2</sub>Cl (diethylaluminum chloride), these cobalt complexes all exhibited high catalytic activity (up to 2.5 × 10<sup>6</sup> g·mol<sub>Co</sub><sup>−1</sup>·h<sup>−1</sup>), affording <i>cis</i>-1,4-<i>co</i>-3,4-polyisoprene with molecular weights of 4.4–176 kg mol<sup>−1</sup> and a narrow Ð of 1.79–3.42, suggesting a single-site nature of the active sites. The structure of cobalt catalysts and reaction parameters, especially co-catalysts and the reaction temperature, all have significant influence on the polymerization activity but not on the microstructure of polyisoprene.https://www.mdpi.com/2073-4360/16/5/578pyridine–oxazoline ligandcobalt catalystisoprene polymerizationisoprene |
| spellingShingle | Xiuge Hao Jin-Kui Liu Weize Zhuo Jiajing Zheng Xin-Qi Hao Jun-Fang Gong Hui Jiang Mao-Ping Song Synthesis, Characterization, and Catalytic Behaviors in Isoprene Polymerization of Pyridine–Oxazoline-Ligated Cobalt Complexes Polymers pyridine–oxazoline ligand cobalt catalyst isoprene polymerization isoprene |
| title | Synthesis, Characterization, and Catalytic Behaviors in Isoprene Polymerization of Pyridine–Oxazoline-Ligated Cobalt Complexes |
| title_full | Synthesis, Characterization, and Catalytic Behaviors in Isoprene Polymerization of Pyridine–Oxazoline-Ligated Cobalt Complexes |
| title_fullStr | Synthesis, Characterization, and Catalytic Behaviors in Isoprene Polymerization of Pyridine–Oxazoline-Ligated Cobalt Complexes |
| title_full_unstemmed | Synthesis, Characterization, and Catalytic Behaviors in Isoprene Polymerization of Pyridine–Oxazoline-Ligated Cobalt Complexes |
| title_short | Synthesis, Characterization, and Catalytic Behaviors in Isoprene Polymerization of Pyridine–Oxazoline-Ligated Cobalt Complexes |
| title_sort | synthesis characterization and catalytic behaviors in isoprene polymerization of pyridine oxazoline ligated cobalt complexes |
| topic | pyridine–oxazoline ligand cobalt catalyst isoprene polymerization isoprene |
| url | https://www.mdpi.com/2073-4360/16/5/578 |
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