合成了9种N,O-配体化合物L¹~L⁹. 化合物L¹~L⁴分别与0.5 equiv. Co₂(CO)₈发生氧化还原配位反应生成中性单核钴化合物1~4; L⁵~L⁷分别与1 equiv. Co₂(CO)₈发生歧化和氧化还原配位反应; L⁸与5/6 equiv. Co₂(CO)₈以及1.2 equiv. MeOH和0.4 equiv. H₂O发生歧化和氧化还原配位反应; L⁹与0.5 equiv. Co₂(CO)₈发生歧化配位反应生成同钴核离子对化合物5~9. 这些化合物中的阴离子均为[Co(CO)₄]^–. 相应地, 化合物8中的阳离子是三核钴簇, 其它化合物中的阳离子都是单核钴. 化合物1~9通过FT-IR谱学表征和元素分析数据确定, 其中1和8进一步经过X射线单晶结构确认.考察了化合物1~9催化环氧丙烷(PO)羰化酯化的性能, 获得42.6%~99.0%的PO转化率和34.1%~88.6%的β-羟基丁酸甲酯(HMB)总产率. 研究了8和9随时间变化的催化反应, 推测了同钴核离子对协同作用的催化反应机理.

Nine N,O-ligands L¹~L⁹ have been synthesized. L¹~L⁴ each reacted with half equivalent Co₂(CO)₈ by redox coordination to produce neutral mononuclear cobalt compounds 1~4. Reactions of L⁵~L⁹ each with equivalent Co₂(CO)₈ occurred by disproportionation and redox coordination to afford 5~7. When the reaction of L⁸, 5/6 equiv. of Co₂(CO)₈, 1.2 equiv. of MeOH, and 0.4 equiv. of H₂O took place via disproportionation and redox coordination to give compound 8, L⁹ and 0.5 equiv. of Co₂(CO)₈ happened through disproportionation coordination to form compound 9. Compounds 5~9 are all the ionic species with the same anion [Co(CO)₄]^–, but coupled by mononuclear cobalt cation for 5~7 and 9 whereas trinuclear cation for 8. Compounds 1~9 have been characterized by FT-IR spectroscopies and elemental analysis, of which 1 and 8 were further determined by X-ray crystallography. The catalytic property of propylene oxide (PO) carbonylation hydroesterification using 1~9 was investigated, achieving PO conversions of 42.6%~99.0% and β-hydroxy methylbutyrate (HMB) yields of 34.1%~88.6%. The time-traced reactions were carried out for both catalysts 8 and 9, and the catalytic reaction mechanism based on cooperative interplay by the homonuclear cobalt ion pair was discussed as well.