Predicting ligand removal energetics in thiolate-protected nanoclusters from molecular complexes
Predicting ligand removal energetics in thiolate-protected nanoclusters from molecular complexes
复制标题
预测分子复合物中硫醇盐保护的纳米团簇中的配体去除能量
DOI：
10.1039/d0nr07839e
复制
发表时间：
2021
期刊：
影响因子：
6.7
通讯作者：
Mpourmpakis, Giannis
中科院分区：
文献类型：
--
作者：
McKay, Julia;Cowan, Michael J.;Morales-Rivera, Cristian A.;Mpourmpakis, Giannis
硫醇盐保护的金属纳米团簇（TPNC）由于其高稳定性、原子精确的结构和引人注目的物理化学性质在过去几十年中引起了极大的兴趣。在它们的各种应用中，TPNC对许多反应表现出优异的催化活性;然而，最近的工作表明，这些系统必须进行部分配体去除，以产生活性位点。尽管配体去除在TPNC的催化和稳定性中的重要性，但是配体和金属类型在该过程中的作用还没有很好地理解。在这里，我们利用密度泛函理论来理解金属-硫和硫-配体键解离金属硫醇盐系统之间的能量相互作用。我们首先在M = Ag、Au和Cu与22种不同配体（R）的组合中探测66种金属硫醇盐分子络合物。我们的研究结果表明，能量打破金属-硫和硫-配体键是强烈相关的，可以连接在所有的配合物通过金属原子电离势。然后，我们将我们的工作扩展到实验相关的[M25（SR）18]-TPNC，揭示了纳米团簇水平上相同的相关性。重要的是，我们统一我们的工作，通过引入一个简单的方法来预测TPNC配体去除能量完全从金属配体分子配合物上进行的计算。最后，进行了计算机理研究，以调查氢化途径的SCH 3为基础的配合物。这些系统的能垒显示，除了热力学，动力学有利于打破的S-R的M-S键的情况下，Au络合物。我们的计算结果合理的几个实验观察有关的配体对TPNC的影响。总的来说，我们介绍的模型提供了一个加速的路径来预测TPNC配体去除能量，从而有助于有针对性地设计TPNC催化剂。
Thiolate-protected metal nanoclusters (TPNCs) have attracted great interest in the last few decades due to their high stability, atomically precise structure, and compelling physicochemical properties. Among their various applications, TPNCs exhibit excellent catalytic activity for numerous reactions; however, recent work revealed that these systems must undergo partial ligand removal in order to generate active sites. Despite the importance of ligand removal in both catalysis and stability of TPNCs, the role of ligands and metal type in the process is not well understood. Herein, we utilize Density Functional Theory to understand the energetic interplay between metal–sulfur and sulfur–ligand bond dissociation in metal–thiolate systems. We first probe 66 metal–thiolate molecular complexes across combinations of M = Ag, Au, and Cu with twenty-two different ligands (R). Our results reveal that the energetics to break the metal–sulfur and sulfur–ligand bonds are strongly correlated and can be connected across all complexes through metal atomic ionization potentials. We then extend our work to the experimentally relevant [M25(SR)18]− TPNC, revealing the same correlations at the nanocluster level. Importantly, we unify our work by introducing a simple methodology to predict TPNC ligand removal energetics solely from calculations performed on metal–ligand molecular complexes. Finally, a computational mechanistic study was performed to investigate the hydrogenation pathways for SCH3-based complexes. The energy barriers for these systems revealed, in addition to thermodynamics, that kinetics favor the break of S–R over the M–S bond in the case of the Au complex. Our computational results rationalize several experimental observations pertinent to ligand effects on TPNCs. Overall, our introduced model provides an accelerated path to predict TPNC ligand removal energies, thus aiding towards targeted design of TPNC catalysts.