Benzimidazole–triazole ligands with pendent triazole functionality: unexpected formation and effects on copper-catalyzed aerobic alcohol oxidation
作者:Manisa Kongkaew、Kannika Sitthisuwannakul、Vasut Nakarajouyphon、Soraya Pornsuwan、Palangpon Kongsaeree、Preeyanuch Sangtrirutnugul
DOI:10.1039/c6dt02770a
日期:——
potentials for 4a–4c. Catalytic activities for aerobic oxidation of benzyl alcohol to benzaldehyde follow this trend: 4c > 4a > 4b. In addition, the catalytic system 4c/TEMPO/Cu0/NMI (TEMPO = 2,2,6,6-tetramethyl-1-piperidinyloxyl, NMI = N-methylimidazole) exhibited high activities for oxidation of activated alcohols (i.e., benzyl alcohol derivatives and allylic alcohol) in CH3CN at room temperature.
适度获得了一系列苯并咪唑-三唑配体(NN'),它们具有悬垂的三唑臂,并带有不同的三唑取代基,包括CH 2 Ph(3a),环-C 6 H 11(3b)和CH 2 SiMe 3(3c)相应的胺-三唑化合物N,N'-双(((R-1,2,3-三唑-4-基)甲基)苯-1,2-二胺(2a–2c)。一当量处理CuCl 2。苯并咪唑–三唑配体的合成提供了相应的Cu II配合物的经验公式为Cu(NN')Cl 2(4a–4c)。4b和4c的晶体结构分别显示单核和双核Cu II配合物。尽管三唑取代基及其固态结构有所不同,但ESR光谱显示CH 3 CN溶液中的分子结构相同,而CV数据表明4a–4c的氧化还原电位相似。苯甲醇有氧氧化为苯甲醛的催化活性遵循以下趋势:4c > 4a > 4b。另外,催化体系4c / TEMPO / Cu 0/ NMI(TEMPO = 2,2,6,6-四甲基-1-哌啶基氧基,NMI = N-甲基咪唑)在室温下对CH