Multi-active Site Dynamics on a Molecular Cr/Co/Se Cluster Catalyst
Multi-active Site Dynamics on a Molecular Cr/Co/Se Cluster Catalyst
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Cr/Co/Se 分子簇催化剂上的多活性位点动力学
DOI：
10.1021/jacs.2c00234
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发表时间：
2022
影响因子：
15
通讯作者：
Velian, Alexandra
中科院分区：
文献类型：
--
作者：
Kephart, Jonathan A.;Mitchell, Benjamin S.;Kaminsky, Werner;Velian, Alexandra
本研究揭示了原子级精确的纳米簇Cr 3（py）3Co 6Se 8L 6（1（py）3，L = Ph 2 PNTol-，Ph =苯基，Tol = 4-甲苯基）的三个催化活性中心的相互关联的反应性。对甲苯磺酰叠氮化物活化和碳二亚胺形成的催化和化学计量研究使关键的催化活性金属-亚氨基中间体，包括三（亚氨基）簇1（NTs）3，催化静止状态1（NTs）3（CNTBu）3，和站点分化的单（亚氨基）簇1（NTs）（CNTBu）2的分离和晶体学表征成为可能。在化学计量的制度，氮烯转移进行通过逐步机制，与三个活性位点接合顺序产生碳二亚胺。此外，相邻的活性位点的化学状态被发现调节一个单独的Cr-亚氨基边缘网站的基板的亲和力，所揭示的比较结构分析和CNTBu结合研究。
This study uncovers the interconnected reactivity of the three catalytically active sites of an atomically precise nanocluster Cr3(py)3Co6Se8L6(1(py)3, L = Ph2PNTol–, Ph = phenyl, Tol = 4-tolyl). Catalytic and stoichiometric studies into tosyl azide activation and carbodiimide formation enabled the isolation and crystallographic characterization of key catalytically competent metal-imido intermediates, including the tris(imido) cluster1(NTs)3, the catalytic resting state1(NTs)3(CNtBu)3, and the site-differentiated mono(imido) cluster1(NTs)(CNtBu)2. In the stoichiometric regime, nitrene transfer proceeds via a stepwise mechanism, with the three active sites engaging sequentially to produce carbodiimide. Moreover, the chemical state of neighboring active sites was found to regulate the affinity for substrates of an individual Cr-imido edge site, as revealed by comparative structural analysis and CNtBu binding studies.