Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D45470 Mülheim an der Ruhr, Germany.
J Am Chem Soc. 2013 Aug 14;135(32):11803-8. doi: 10.1021/ja3116247. Epub 2013 Jul 30.
This work establishes the ability of valence-to-core X-ray emission spectroscopy (XES) to serve as a direct probe of N2 bond activation. A systematic series of iron-N2 complexes has been experimentally investigated and the energy of a valence-to-core XES peak was correlated with N-N bond length and stretching frequency. Computations demonstrate that, in a simple one-electron picture, this peak arises from the N2 2s2s σ* orbital, which becomes less antibonding as the N-N bond is weakened and broken. Changes as small as 0.02 Å in the N-N bond length may be distinguished using this approach. The results thus establish valence-to-core XES as an effective probe of small molecule activation, which should have broad applicability in transition-metal mediated catalysis.
这项工作证实了价壳层 X 射线发射光谱（XES）作为直接探测 N2 键活化的能力。通过实验研究了一系列铁-N2 配合物，价壳层 XES 峰的能量与 N-N 键长和拉伸频率相关联。计算表明，在一个简单的单电子图像中，该峰源于 N2 的 2s2sσ*轨道，随着 N-N 键的削弱和断裂，它变得越来越不反键。使用这种方法可以区分 N-N 键长的微小变化，例如 0.02 Å。因此，价壳层 XES 被确立为小分子活化的有效探针，它在过渡金属介导的催化中应该具有广泛的适用性。
