Cobalt Carbonyls Stabilized by N,P‐Ligands: Synthesis, Structure, and Catalytic Property for Ethylene Oxide Hydroalkoxycarbonylation

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.

Synthesis and Propylene Oxide Carbonylation Hydroesterification Catalytic Property of N,O-Ligand Coordination Cobalt Compounds

“…配体或助剂与 Co 2 (CO) 8 进 一步反应, 能够产生稳定的金属 Co 活性中心, 被认为 是合适的催化剂体系. 近年来, 我们 [7] 使用 N,P-配体合 成了系列双核 Co 化合物以及同 Co 核离子对化合物, 这 些化合物高效催化环氧乙烷(EO)、一氧化碳和甲醇羰化 酯化合成 β-羟基丙酸甲酯 [8] , 其中催化剂的合成方法更高效, 本文将报道这些研究结果.…”