Abstract Pd(II)-bis(NHC) complexes (where NHC = N-heterocyclic carbene) bearing asymmetrically and symmetrically substituted NHC-ligand have been synthesized via deprotonation of 5,6-dimethylbenzimidazolium salts. The NHC precursors have been achieved via the two step N-alkylation of 5,6-dimethylbenzimidazole. The resultant salts were deprotonated with PdCl2 and K2CO3 in dry THF for 2(a–e). The obtained complexes were identified and characterized by 1H and 13C NMR, FT-IR, DART-TOF mass spectrometry and elemental analysis. These new Pd(II)-bis(NHC) complexes were applied as catalyst precursors for Suzuki-Miyaura cross-coupling reactions of aryl bromides and chlorides with phenylboronic acid to afford the corresponding products in good yields. This catalytic reaction was evaluated in the presence of KOtBu/toluene. The antibacterial activities of 2(a–e) were investigated against Gram (+)/(−) bacteria using the agar dilution procedure. The antibacterial activities of 2 vary with the nature of the ligands; MIC values of 2(a–e) were determined.

中文翻译：

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生物活性 NHC 衍生的钯配合物：芳基氯化物和溴化物的 Suzuki-Miyaura 偶联的合成、催化活性及其抗菌活性

摘要 通过 5,6-二甲基苯并咪唑鎓盐的去质子化合成了带有不对称和对称取代的 NHC 配体的 Pd(II)-双 (NHC) 配合物（其中 NHC = N-杂环卡宾）。NHC 前体是通过 5,6-二甲基苯并咪唑的两步 N-烷基化获得的。所得盐在干燥 THF 中用 PdCl2 和 K2CO3 去质子化 2(a-e)。所得配合物通过 1H 和 13C NMR、FT-IR、DART-TOF 质谱和元素分析进行​​鉴定和表征。这些新的 Pd(II)-双 (NHC) 配合物用作芳基溴化物和氯化物与苯基硼酸的 Suzuki-Miyaura 交叉偶联反应的催化剂前体，以良好的产率提供相应的产物。该催化反应在 KOtBu/甲苯的存在下进行评估。使用琼脂稀释程序研究了 2(a-e) 对革兰氏 (+)/(-) 细菌的抗菌活性。2的抗菌活性随配体的性质不同而不同；确定了 2(a-e) 的 MIC 值。