3-(2-Propenyl)benzothiazolium bromide (A) provides a direct and simple entry to Pd(II) complexes with N,S-heterocyclic carbene (NSHC) ligands functionalized with an allyl pendant with hemilabile potential. Addition of salt A to Pd(OAc)2 eliminates HOAc and affords the bis(carbene) complexes cis-[PdBr2(NHSC)2] (cis-1, NSHC = 3-(2-propenyl)benzothiazolin-2-ylidene) and trans-[PdBr2(NHSC)2] (trans-1) along with the monocarbene complexes [PdBr2(NSHC)] (2) and trans-[PdBr2(benzothiazole-κN)(NSHC)] (3) as minor side products. Salt-metathesis of cis-1 with AgO2CCF3 yields the mixed dicarboxylato-bis(carbene) complex cis-[Pd(O2CCF3)2(NSHC)2] (4). Complexes cis-1, trans-1 and 4 were characterized by multinuclear NMR spectroscopies, ESI mass spectrometry and elemental analysis. The molecular structures of complexes cis-1, 2 and 3 have been determined by X-ray single crystal diffraction. Complexes cis-1 and 4 as well as an in situ mixture of Pd(OAc)2 and salt A are active toward Suzuki–Miyaura coupling of aryl bromides and activated aryl chlorides giving good conversions.
溴化3-(2-
丙烯基)
苯并噻唑鎓盐(A)为制备含有功能化的烯丙基半可键合N,S-杂环卡宾(NSHC)
配体的
钯(II)配合物提供了一个直接且简单的途径。将盐A加入到Pd(OAc)2中会消除HOAc,并得到双卡宾配合物cis-[PdBr2(NHSC)2](cis-1,其中NSHC=3-(2-
丙烯基)
苯并噻唑啉-2-亚基)和trans-[PdBr2(NHSC)2](trans-1),同时还产生次要副产物单卡宾配合物[PdBr2(NSHC)](2)和trans-[PdBr2(
苯并噻唑-κN)(NSHC)](3)。通过与AgO2CCF3进行盐交换反应,cis-1生成了混合二
羧酸根-双卡宾配合物cis-[Pd(O2CCF3)2(NSHC)2](4)。配合物cis-1、trans-1和4通过多核NMR光谱学、ESI质谱法和元素分析进行了表征。配合物cis-1、2和3的分子结构通过X射线单晶衍射确定。配合物cis-1和4以及Pd(OAc)2和盐A的原位混合物对于Suzuki–Miyaura交叉偶联反应中的芳基
溴和活化芳基
氯具有活性,提供了良好的转化率。