Both imidazol-2-ylidene (ImNHC) and 1,2,3-triazol-5-ylidene (tzNHC) have evolved to be elite groups of N-heterocyclic carbene (NHC) ligands for homogeneous catalysis. To develop efficient ruthenium(II)-based catalysts incorporating these ligands for C-N bond-forming reactions via hydrogen-borrowing methodology, we utilized chelating ligands integrated with ImNHC and mesoionic tzNHC donors connected via a CH2 spacer with a diverse triazole backbone. The synthesized ruthenium(II) complexes 3 are found to be highly efficient for C-N bond formation across a wide range of primary amine and alcohol substrates under solvent-free conditions, and among all of the complexes studied here, catalyst 3a with a mesityl substituent displayed maximum activity. To our delight, catalyst 3a is also effective for the selective mono-N-methylation of various anilines utilizing methanol as a coupling partner, known to be relatively more difficult than other alcohols. Furthermore, complex 3a also delivers various substituted quinolines successfully via the reaction of 2-aminobenzyl alcohol with several secondary alcohols. Importantly, catalyst 3a exhibited the highest activity among the reported ruthenium(II) complexes for both the N-benzylation of aniline [achieving a turnover number (TON) of 50000] and the realization of quinoline 8a by reacting 2-aminobenzyl alcohol with 2-phenylethanol (attaining a TON of 30000).

中文翻译：

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异位N-杂环碳配体的钌（II）配合物：在无溶剂条件下通过氢借入策略形成CN键的高效催化剂。

咪唑-2-亚烷基（ImNHC）和1,2,3-三唑-5-亚烷基（tzNHC）均已发展成为用于均相催化的N-杂环卡宾（NHC）配体的精英基团。为了开发通过氢借用方法将这些配体用于CN键形成反应的高效钌（II）基催化剂，我们利用了与ImNHC和通过CH2间隔基与不同的三唑骨架连接的中型tzNHC供体集成的螯合配体。发现合成的钌（II）配合物3在无溶剂条件下能在各种伯胺和醇底物上高效形成CN键，并且在本文研究的所有配合物中，均显示了具有甲磺酰基取代基的催化剂3a最大的活动。令我们高兴的是，催化剂3a对于利用甲醇作为偶合伴侣的各种苯胺的选择性单-N-甲基化也是有效的，众所周知，甲醇作为偶合伴侣比其他醇相对困难。此外，配合物3a还通过2-氨基苄醇与几种仲醇的反应成功地递送了各种取代的喹啉。重要的是，催化剂3a在所报道的钌（II）络合物中对苯胺的N-苄基化[实现营业额（TON）为50000]和通过使2-氨基苄醇与2-氨基反应实现喹啉8a表现出最高的活性。苯乙醇（TON达到30000）。配合物3a还可以通过2-氨基苄醇与几种仲醇的反应成功地提供各种取代的喹啉。重要的是，催化剂3a在所报道的钌（II）络合物中对苯胺的N-苄基化[实现营业额（TON）为50000]和通过使2-氨基苄醇与2-氨基反应实现喹啉8a表现出最高的活性。苯乙醇（TON达到30000）。配合物3a还可以通过2-氨基苄醇与几种仲醇的反应成功地提供各种取代的喹啉。重要的是，催化剂3a在所报道的钌（II）络合物中对苯胺的N-苄基化[实现营业额（TON）为50000]和通过使2-氨基苄醇与2-氨基反应实现喹啉8a表现出最高的活性。苯乙醇（TON达到30000）。