Postmodification Approach to Charge-Tagged 1,2,4-Triazole-Derived NHC Palladium(II) Complexes and Their Applications
作者:Van Ha Nguyen、Mansur B. Ibrahim、Waseem W. Mansour、Bassam M. El Ali、Han Vinh Huynh
DOI:10.1021/acs.organomet.7b00329
日期:2017.6.26
Charge-tagged bis(1,2,4-triazolin-5-ylidene)palladium(II) complexes have been successfully synthesized via a postmodification strategy. Reacting PdBr2 with bromo-functionalized 1,2,4-triazolium salts A·HBr and B·HBr in the presence of silver oxide afforded the bis(carbene)palladium(II) complexes trans-[PdBr2(A)2] (1a) and trans-[PdBr2(B)2] (1b), which contain tethered bromoalkyl chains. Subsequent
电荷标记的双(1,2,4-三唑啉-5-亚烷基)钯(II)配合物已通过后修饰策略成功合成。在氧化银存在下,将PdBr 2与溴官能化的1,2,4-三唑鎓盐A ·HBr和B ·HBr反应,得到反式-[PdBr 2(A)2 ]的双(卡宾)钯(II)配合物(1a)和反式-[PdBr 2(B)2 ](1b),其中包含束缚的溴烷基链。随后的后配位亲核取代将溴转化为铵基,从而生成水溶性复合物反式-[PdBr 2(C)2 ] Br 2(2a)和反式-[PdBr 2(D)2 ] Br 2(2b)),虽然尝试制备铵官能化的三唑鎓盐进行直接金属化是徒劳的。借助多核NMR光谱,ESI质谱,元素分析和X射线衍射分析,对这四种配合物进行了全面表征。通过1 H和13 C NMR光谱和理论计算来阐明溶液中反式和反式旋转异构体的存在。此外,两个电荷标记的复合物,图2a,b,被认为是为铃木-宫浦和高活性的预催化剂Mizoroki-的Heck反应中我异丙醇/