Robust and Electron-Rich<i>cis</i>-Palladium(II) Complexes with Phosphine and Carbene Ligands as Catalytic Precursors in Suzuki Coupling Reactions
作者:Chuang-Yi Liao、Kai-Ting Chan、Cheng-Yi Tu、Yu-Wei Chang、Ching-Han Hu、Hon Man Lee
DOI:10.1002/chem.200801296
日期:2009.1.2
A new imidazolinium ligand precursor [L2H]Cl (2) was prepared in 86 % yield. Compared with its imidazolium counterpart, [L1H]Cl (1), 2 is very sensitive to moisture and can undergo ring‐opening reactions very readily. Palladium complexes with the ring‐opened products from imidazolinium salts were isolated and characterized by X‐ray crystallography. Theoretical studies confirmed that the imidazolinium
以86%的收率制备了新的咪唑啉鎓配体前体[L 2 H] Cl(2)。与它的咪唑鎓对应物[L 1 H] Cl(1)相比,2对水分非常敏感,并且很容易发生开环反应。分离了具有咪唑啉鎓盐的开环产物的钯配合物,并通过X射线晶体学对其进行了表征。理论研究证实,咪唑啉盐比咪唑鎓盐具有更高的开环反应倾向。新的膦/卡宾钯混合复合物,顺式[PdCl 2(L)(PR 3)](L = L 1和L 2; R = Ph,Cy)已成功制备。可变温度NMR光谱研究和热重分析表明,这些配合物具有很高的鲁棒性。在不同的卡宾基团上的新配合物的结构和电子性质(咪唑-2-亚基(不饱和卡宾)与咪唑啉-2-亚基(饱和卡宾))和膦基(PPh 3与PCy 3)为通过X射线晶体学,X射线光电子能谱和理论计算进行了详细研究。催化研究表明,顺式-[PdCl 2(L 2)(PCy 3)]是合格的Pd II 铃木偶联反应的前催化剂,其中不活泼的芳基氯可用作底物。