Transition metal complexes of cyclic and open ozone and thiozone
Transition metal complexes of cyclic and open ozone and thiozone
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DOI：
10.1021/ja044809d
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发表时间：
2005-02-02
影响因子：
15
通讯作者：
Hoffmann, R
中科院分区：
文献类型：
--
作者：
Flemmig, B;Wolczanski, PT;Hoffmann, R
循环臭氧（O-3）迄今尚未被隔离，尽管它的计算动力学持久性。本文研究了在过渡金属配合物中“捕获”该分子（或称价等电子环硫酮，S-3）的可能性。首先使用18电子规则作为指导，然后使用DFT-B3 LYP方法优化结构，构建候选物。各种结构的结果：氧-过氧物种，二-sigma-和pi-键合开放臭氧复合物，一些eta（1）和eta（2）环状臭氧复合物，和一些真正的eta（3）环状O-3和S-3复合物。适合于复合物形成的MLn片段将需要含有非常强的π-受体配体。选择亚硝酰基配体以使O-3供体轨道和MLn受体轨道之间的能量失配最小化。在此基础上，提出了[S_3W（NO）（3）]（3+），[O_3M（NO）（3）]（3+）（M = Cr，Mo，W，Fe，Ru，Os）和[S_3W（NO）（2）（Co）]（2+）等含环O-3和S-3的配合物的存在。在另一种方法中，面对O-3的氧化能力，从高氧化态的后过渡金属和早期过渡金属中心建立潜在的系统。
Cyclic ozone (O-3) has not been isolated so far, despite its computed kinetic persistence. Possibilities of "trapping" this molecule (or the valence-isoelectronic cyclic thiozone, S-3) in transition metal complexes are investigated in this paper. Candidates were constructed, first using the 18-electron rule as a guide and then optimizing the structures with the DFT-B3LYP method. A variety of structures result: oxo-peroxo species, di-sigma- and pi-bonded open ozone complexes, some eta(1) and eta(2) cyclic ozone complexes, and a few bona fide eta(3) Cyclic O-3 and S-3 complexes. MLn fragments suitable for complex formation would need to contain very strong pi-acceptor ligands. Nitrosyl ligands were chosen to minimize an energy mismatch between the O-3 donor orbitals and the MLn acceptor orbitals. On this basis, the existence of the complexes [S3W(NO)(3)](3+), [O3M(NO)(3)](3+) (M = Cr, Mo, W, Fe, Ru, Os), and [S3W(NO)(2)(Co)](2+) containing cyclic O-3 and S-3 is suggested. In another approach, facing up to the oxidizing power of O-3, potential systems were built from late transition metals in high oxidation states, and also do early transition metal centers.