In this contribution, a series of sterically–encumbered coumarin substituted benzimidazole–based N–heterocyclic carbene (NHC) precursors (1−12) and their silver(I)–NHC complexes (13–24) are reported. Molecular structure of NHC precursors 8 and 12 and cationic complexes 15 and 16 was established by single crystal X–ray diffraction method. The silver(I) complexes demonstrated various significant intramolecular agostic–like interactions operating between the metal center and the hydrogen atoms of the substituents alongside a variety of feeble π–π stacking interactions. A distorted linear coordination geometry is documented at the silver(I) center with the anti–arrangement of the ligands. Further, the complexes demonstrated promising antibacterial properties against Gram positive and Gram negative bacterial strains, especially complex 18 displayed a minimum inhibitory concentration (MIC) of 2 and 4 μg/mL against S. aureus and E. coli, and P. aeruginosa, respectively. Furthermore, complexes 14, 15, 16 and 18 were found cytotoxic against the human lung cancer cell lines A549 and H1975 with the IC₅₀ (concentration of the test sample required to kill 50% of the cell population) value under 10 μM, while mono–NHC complex 20 displayed a potential drug window with the IC₅₀ of 13.7 ± 2.70 and 14.5 ± 1.20 μM against the cancer cell lines H1975 and A549, respectively. Notably, these complexes displayed relatively lesser cytotoxic behaviour against the normal skin fibroblast cell line, Hs68. All the NHC precursors displayed significantly lower biological activities compared with their respective complexes, indicating the utility of silver(I) ions in antimicrobial and antilung cancer applications.

在此贡献中，一系列的空间位作保香豆素取代的苯并咪唑为基础的N-杂环卡宾（NHC）的前体（1 - 12（I） - NHC络合物及其银（）13 - 24）的报告。NHC前体8和12以及阳离子配合物15和16的分子结构通过单晶X射线衍射法建立。银（I）配合物表现出各种显着的分子内类似分子的相互作用，在金属中心和取代基的氢原子之间起作用，同时还具有各种微弱的π-π堆积相互作用。在银（I）中心记录了扭曲的线性配位几何，其中配体的反排列。此外，该复合物表现出对革兰氏阳性和革兰氏阴性细菌菌株的有希望的抗菌性能，尤其是复合物18对S的最小抑菌浓度（MIC）为2和4μg/ mL 。金黄色葡萄球菌和Ë。大肠杆菌和P。分别为铜绿。此外，复合物14，15，16和18中发现的细胞毒性对人肺癌细胞系A549和H1975与IC ₅₀（测试样品的浓度所需要杀死细胞群体的50％）下10μM值，而单–NHC配合物20与IC ₅₀一起显示了潜在的药物窗口分别针对癌细胞系H1975和A549的13.7±2.70和14.5±1.20μM。值得注意的是，这些复合物对正常皮肤成纤维细胞系Hs68表现出相对较小的细胞毒性行为。与它们各自的复合物相比，所有NHC前体均显示出明显较低的生物活性，这表明银（I）离子在抗微生物和抗肺癌应用中的效用。