Relevance of Chemical vs. Electrochemical Oxidation of Tunable Carbene Iridium Complexes for Catalytic Water Oxidation
作者:Marta Olivares、Cornelis J. M. van der Ham、Velabo Mdluli、Markus Schmidtendorf、Helge Müller‐Bunz、Tiny W. G. M. Verhoeven、Mo Li、J. W. (Hans) Niemantsverdriet、Dennis G. H. Hetterscheid、Stefan Bernhard、Martin Albrecht
DOI:10.1002/ejic.202000090
日期:2020.3.15
the triazolylidene fragment outperforms complex 10 by a factor of 5, while in CAN-mediated chemical water oxidation, complex 10 is twice more active than 8b. This discrepancy in catalytic activity is remarkable and indicates that caution is needed when benchmarking iridium water oxidation catalysts with chemical oxidants, especially when considering that application in a potential device will most likely
基于之前的工作,确定了含有 C,N-二齿螯合三唑亚-吡啶基配体(Cp* = 五甲基环戊二烯基,C 5Me 5 –)的铱 (III) Cp* 配合物是有效的分子水氧化催化剂,一系列基于该基序的设计和合成是为了提高催化活性。修饰特别包括将给电子取代基引入螯合配体的吡啶基单元(H,a;5-OMe,b;4-OMe,c;4-tBu,d;4-NMe 2,e),如以及三唑亚基 C4 位置上的电子活性取代基 (H, 8; COOEt, 9; OEt, 10; OH, 11; COOH, 12)。使用硝酸铈铵 (CAN) 进行的化学氧化表明与提高催化转换频率的给电子基团存在明显的构效关系,尤其是当供体取代基位于三唑基配体片段上时(对于在pyr和OEt取代的三唑基上具有MeO基团的复合物10,TOF max = 2500 h – 1,而没有取代基的母体基准复合物的TOF max = 2500 h – 1) .