Switching electronic effects of UiO-67-Pd using fluorinated ligands for catalytic oxidative arylation of bio-based furfuryl alcohol  

含氟配体修饰UiO-67-Pd催化生物基醇氧化芳基化反应的电子调控效应

作　　者：Dongwen Guo Guohui Zeng Jinxing Long Biaolin Yin 郭栋稳;曾国辉;龙金星;尹标林(华南理工大学化学与化工学院,广东省功能分子工程重点实验室,纸浆造纸工程国家重点实验室,广东广州510640)

机构地区：[1]Key Laboratory of Functional Molecular Engineering of Guangdong Province,State Key Laboratory of Pulp and Paper Engineering,School of Chemistry and Chemical Engineering,South China University of Technology,Guangzhou 510640,Guangdong,China

出　　处：《Chinese Journal of Catalysis》2025年第2期230-240,共11页催化学报(英文)

基　　金：国家自然科学基金(22178129);广东省自然科学基金(2023A1515010771)。

摘　　要：An efficient and novel approach is proposed for oxidative arylation of bio-based furfuryl alcohol(FA)to aryl furans(AFs),a versatile monomer of photoelectric materials,in the presence of UiO-67-Pd(F)with phenanthroline/bipyridine,and poly-F substituted phenyl ligands as the mixture linkers.The results of control experiments and theoretical calculations reveal that the–F on the phenyl linkers efficiently tunes the electron-deficient nature of Pd through the Zr_(6) clusters bridges,which favors the adsorption and activation of the furan ring.Furthermore,the conjugation of different nitrogen-containing ligands facilitates Pd coordination for the Heck-type insertion and subsequent electrophilic palladation,respectively.As a result,the oxidative arylation of FA derivatives is substantially enhanced because of these electronic and steric synergistic effects.Under the optimized conditions,72.2%FA conversion and 74.8%mono aryl furan(MAF)selectivity are shown in the Heck-type insertion.Meanwhile,85.3%of MAF is converted,affording 74.8%selectivity of final product(AFs)in the subsequent electrophilic palladation reaction.This process efficiency is remarkably higher than that with homogeneous catalysts.In addition,furan-benzene polymer obtained from the halogen-free synthesis catalyzed by UiO-67-Pd(F)show significantly better properties than that from conventional Suzuki coupling method.Therefore,the present work provides a new insight for useful AFs synthesis by oxidative arylation of bio-furan via rational tunning the metal center micro-environment of heterogeneous catalyst.作为一种高附加值的单体分子,芳基喃(AFs)广泛应用于光电材料、天然产物、药物分子和生物燃料等领域.该化合物通常以芳基硼酸和芳基卤化物为原料,通过催化Suzuki偶联的方式合成得到然而,使用含卤素原料有违绿色化学的理念.因而,利用易得、可再生的生物基呋喃和芳基硼酸作为底物,通过钯催化氧化偶联将是一种很有前途的替代方法.尤其是,该方法具有无卤、过程经济性高、使用氧气作为氧化剂的优点,近年来受到广泛关注.然而,现有的均相催化体系存在催化剂分离和回收难、需要使用有毒配体和共氧化剂,且均相催化氧化芳基化的Heck插入或亲电钯化过程易伴生富电子呋喃环和伯羟基的氧化等副反应.因此,发展基于电子和空间协同效应的高效非均相钯催化体系具有重要的意义本文以菲罗啉/联吡啶和多氟取代的苯基配体作为混合连接剂,发展了新颖的UiO-67-Pd(F)催化剂,实现了生物基糠醇连续选择性芳基化制备芳基呋喃化合物的过程。粉末X射线衍射、傅里叶变换红外光谱和透射电镜等研究发现,使用多氟取代苯基配体修饰后的UiO-67未改变其拓扑结构,但为钯催化活性中心提供了一个稳定的配位环境.X射线光电子能谱、同步辐射X射线吸收谱和理论计算结果表明,UiO-67-Pd(F)催化剂中含氟配体的引入使得电子通过F-Zr_(6)簇-Pd途径转移,有效地调节了活性中心的缺电子性质,有利于呋喃类底物的吸附和活化在最佳反应条件下,Heck插入步骤的FAs转化率为72.2%,单芳基呋喃(MAF)选择性为74.8%.随后的亲电钯化反应中MAF的转化率为85.3%,最终AFs的选择性为74.8%.值得注意的是,该UiO-67-Pd(F)多相催化剂的活性是现有文献报道中的较好均相体系(Pd(CH_(3)CN)_(2)Cl_(2)或Pd(OAc)_(2))的50倍以上.此外,UiO-67-Pd(F)催化剂在Heck插入和亲电钯化反应中均展现出良好的底物适用性.机理研究表明:�

关 键 词：Bio-based furan Catalytic oxidative arylation UiO-67-Pd(F)catalyst Ligand regulation Charge separation 

分 类 号：O643.36[理学—物理化学]