NHC-Ag修饰的钐配合物催化CO2与端炔的羧化反应

An NHC-Ag modified samarium coordination polymer catalyzed carboxylation of carbon CO2 with terminal alkynes

摘要:

将1,3-二(4-羧基苯甲基)-苯并咪唑鎓氯化物（H2BCBI）与硝酸钐在水热条件下进行反应，得到二维配位聚合物[Sm(BCBI)(NO3)2·H2O]n（Sm-BCBI），将其与AgOAc作用引入NHC-Ag(I)催化位点，制备了氮杂环卡宾-银功能化的钐配合物（NHC-Ag(I)@Sm-BCBI）。通过单晶X-射线衍射、PXRD、TGA、XPS、ICP-OES、SEM和EDS等对Sm-BCBI和NHC-Ag(I)@Sm-BCBI进行表征。结果表明，Sm-BCBI为二维层状结构；NHC-Ag(I)@Sm-BCBI催化剂具有良好的热稳定性，且催化剂中的银以+1价形式存在。将NHC-Ag(I)@Sm-BCBI用于催化CO2（0.1 MPa）与苯乙炔的羧化反应，在反应温度为50 ℃，以Cs2CO3为碱，DMF为溶剂，催化剂用量为70 mg（0.35 mol%），反应时间为16 h的最佳反应条件下，苯丙炔酸分离产率可达80%。且催化剂容易回收，在循环使用4次以后，催化产率仍能达到60%。

Abstract:

A two-dimensional coordination polymer [Sm(BCBI)(NO3)2·H2O]n (Sm-BCBI) was obtained by the reaction of 1,3-bis(4-carboxybenzyl)-benzimidazolium chloride (H2BCBI) with samarium nitrate under hydrothermal conditions. The N-heterocyclic carbene-silver functionalized samarium coordination polymer (NHC-Ag(I)@Sm-BCBI) was prepared by the reaction of Sm-BCBI with AgOAc to introduce the NHC-Ag(I) catalytic sites. Sm-BCBI and NHC-Ag(I)@Sm-BCBI were characterized by single crystal X-ray diffraction, PXRD, TGA, XPS, ICP-OES, SEM and EDS. The results show that Sm-BCBI is a two-dimensional layer structure; the NHC-Ag(I)@Sm-BCBI catalyst has good thermal stability, and the silver in the catalyst exists in the form of +1 valence. The catalyst was applied to the carboxylation reaction of CO2 (0.1 MPa) with phenylacetylene to generate phenylpropiolic acid. Under the optimum reaction conditions of reaction temperature 50 °C, Cs2CO3 as base, DMF as solvent, NHC-Ag(I)@Sm-BCBI catalyst 70 mg (0.35%) and reaction time 16 h, the separation yield reaches 80%. The catalyst is easy to recycle, and the catalytic yield can still reach 60% after 4 cycles.