Department of Chemistry, University of California at Davis, Davis, California 95616, United States.
J Am Chem Soc. 2020 Jul 15;142(28):12299-12305. doi: 10.1021/jacs.0c04034. Epub 2020 Jul 2.
A common approach to speeding up proton transfer (PT) by molecular catalysts is manipulation of the secondary coordination sphere with proton relays and these enhance overall reaction rates by orders of magnitude. In contrast, heterogeneous electrocatalysts have band structures that promote facile PT concerted with electron transfer (ET), known as the Volmer mechanism. Here, we show that [CoC(CO)], containing multiple Co-Co bonds to statistically enhance observed rates of PT, promotes PT on the order of 2.3 × 10 M s which suggests a diffusion-limited rate. The fast ET and PT chemistry is attributed to the delocalized electronic structure of [CoC(CO)]. Electrochemical characterization of [CoC(CO)] in the presence and absence of protons reveals ET kinetics and diffusion behavior similar to other small clusters such as nanomaterials and fullerenes.
一种常见的通过分子催化剂加速质子转移（PT）的方法是用质子中继物来操纵次级配位层，这些质子中继物可将整体反应速率提高几个数量级。相比之下，多相电催化剂具有促进与电子转移（ET）协同的质子转移的能带结构，这被称为沃默尔机制。在这里，我们表明，[CoC(CO)] 含有多个 Co-Co 键，可统计上增强观察到的 PT 速率，其促进 PT 的速率约为 2.3×10^M s^-1，表明这是一个扩散限制的速率。快速的 ET 和 PT 化学反应归因于 [CoC(CO)] 的离域电子结构。在有/没有质子的情况下对 [CoC(CO)] 的电化学特性进行了表征，结果表明 ET 动力学和扩散行为与其他小团簇（如纳米材料和富勒烯）相似。
