Derat Etienne, Kumar Devesh, Neumann Ronny, Shaik Sason
Department of Organic Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel.
Inorg Chem. 2006 Oct 16;45(21):8655-63. doi: 10.1021/ic0610435.
This work uses density functional calculations to design a new high-valent Fe(V)=O catalyst [Mo5O18Fe=O]3-, which is based on the Lindqvist polyoxometalate (Mo6O19(2-)). Because the parent species is stable to oxidative conditions, one may assume that the newly proposed iron-oxo species will be stable, too. The calculated Mössbauer spectroscopic data may be helpful toward an eventual identification of the species. The calculations of C-H hydroxylation and C=C epoxidation of propene show that, if made, [Mo5O18Fe=O]3- should be a potent oxidant that will be subject to strong solvent effect. Moreover, the Lindqvist catalyst leads to an intriguing result; the reaction that starts along an epoxidation pathway with C=C activation ends with a C-H hydroxylation product ((4)6) due to rearrangement on the catalyst. The origins of this result are analyzed in terms of the structure of the catalyst and the electronic requirements for conversion of an epoxidation intermediate to a hydroxylation product. Thus, if made, the [Mo5O18Fe=O]3 will be a selective C-H hydroxylation reagent.
本研究利用密度泛函计算设计了一种新型高价铁（V）=氧催化剂[Mo5O18Fe=O]3-，其基于Lindqvist多金属氧酸盐（Mo6O19(2-)）。由于母体物种对氧化条件稳定，因此可以假定新提出的铁氧物种也将是稳定的。计算得到的穆斯堡尔光谱数据可能有助于最终鉴定该物种。丙烯的C-H羟基化和C=C环氧化计算结果表明，如果合成出[Mo5O18Fe=O]3-，它应该是一种强效氧化剂，并且会受到强烈的溶剂效应影响。此外，Lindqvist催化剂导致了一个有趣的结果；由于催化剂上的重排，以C=C活化开始的环氧化途径的反应最终生成了C-H羟基化产物（(4)6）。根据催化剂的结构以及环氧化中间体转化为羟基化产物的电子需求，对这一结果的起源进行了分析。因此，如果合成出来，[Mo5O18Fe=O]3-将是一种选择性C-H羟基化试剂。
