The effect of electronic modulations on a series of C˄C orthometalated Ru^II-NHC complexes 2-10 was explored in (de)hydrogenation reaction. The electronic tweaking of the complexes was achieved either by varying the carbene donors (ImNHC vs 1,2,4-TzNHC) or the nature and position of the substituents on the N-phenyl wingtip of the NHC ligand. All the synthesized new complexes were fully characterized by using NMR analyses, mass spectrometry as well as X-ray crystallography. The electronic nature of the complexes was ascertained from the electrochemical analyses in addition to ¹³C{¹H} NMR studies. Catalytic activities of the complexes were investigated in the acceptorless dehydrogenation of 1-phenyl-1-propanol to propiophenone, and we observed that Ru^II-NHC complexes containing ImNHC donors outperformed their TzNHC analogues. Further, the Ru^II-ImNHC precatalysts with substituents at the para-position with respect to the imidazolium moiety exhibited an activity trend of electron deficient complexes being more active than that of the electron rich complexes. Whereas the analogous precatalysts with the substituents at meta-position exhibited different activity trend (electron rich complex is superior compared to the electron deficient complexes). Additionally, the complexes were also tested in the transfer hydrogenation of acetophenone and surprisingly, in contrast to dehydrogenation reaction, the meta-substituents had no effect on the transfer hydrogenation activities of the complexes.

在（脱）加氢反应中探索了电子调制对一系列 C˄C 正金属化 Ru ^II -NHC 配合物2 - 10 的影响。通过改变卡宾供体（ImNHC与1,2,4-TzNHC）或 NHC 配体 N-苯基翼尖上取代基的性质和位置，可以实现复合物的电子调整。所有合成的新配合物都通过核磁共振分析、质谱和 X 射线晶体学进行了充分表征。除了¹³ C{ ¹H} 核磁共振研究。在 1-苯基-1-丙醇到苯丙酮的无受体脱氢反应中研究了配合物的催化活性，我们观察到含有 ImNHC 供体的Ru ^II -NHC 配合物的性能优于它们的 TzNHC 类似物。此外，在咪唑部分的对位具有取代基的 Ru ^II -ImNHC 预催化剂表现出缺电子配合物比富电子配合物更活跃的活性趋势。而在间位具有取代基的类似预催化剂-位表现出不同的活性趋势（富电子复合物优于缺电子复合物）。此外，还在苯乙酮的转移氢化中测试了配合物，并且令人惊讶的是，与脱氢反应相反，间位取代基对配合物的转移氢化活性没有影响。