Cobalt Carbonyls Stabilized by N,P-Ligands: Synthesis,Structure, and Catalytic Property for Ethylene Oxide Hydroalkoxycarbonylation |
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| Authors: | Jinbo Zhao Dr Peng Wu Enyi Lai Dr Jiancheng Li Yilin Chen Wenjun Jiang Prof Dr Binju Wang Prof Dr Hongping Zhu |
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| Institution: | State Key Laboratory of Physical Chemistry of Solid Surfaces, National Engineering Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005 P. R. China |
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| Abstract: | Reactions of N,P-Ligands as Ph2P(o-NMe2C6H4) (1L), 2,6-iPr2C6H3NHC(Ph)=NC6H4(o-PPh2) (2L), and Ph2PN(R)PPh2 (R=iPr (3L), cyclo-C6H11 (4L), tBu (5L), CH2C4H7O (6L)) each with dicobalt octacarbonyl produced complexes 1LCo(CO)3]2 ( 1 ), 2LCo(CO)(μ-CO)2Co(CO)3] ( 2 ), 3LCo(CO)3]+Co(CO)4]− ( 3 ), 3LCo(CO)2]2 ( 4 ), 4LCo(CO)2]2 ( 5 ), 5LCo(CO)2]+Co(CO)4]− ( 6 ), and 6LCo(CO)2]+Co(CO)4]− ( 7 ). Complexes 1–7 have all been structurally characterized by X-ray crystallography, IR and NMR spectroscopies, and elemental analysis. Catalytic tests on transformation of ethylene oxide (EO), CO and MeOH into methyl 3-hydroxypropionate (3-HMP) indicate that complexes 1 – 7 are active, where ion-pair complexes 3 and 6 – 7 behave more excellently (by achieving 88.4–93.6% 3-HMP yields) than the neutral species 1 – 2 and 4 – 5 (35.0–46.5% 3-HMP yields) when the reactions are all operated at 2 MPa CO pressure and 50 °C in MeOH solvent. Density functional theory (DFT) study by selecting 3 as a model suggests a cooperative catalytic reaction mechanism by Co(CO)4]− and its counter cation 3LCo(CO)3]+. The cobalt-homonuclear ion-pair catalyzed hydroalkoxycarbonylation of EO is present herein. |
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| Keywords: | crystal structures ethylene oxide hydromethoxycarbonylation homogeneous catalysis homonuclear ion pair |
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