Helmholtz-Zentrum Berlin für Materialien und Energie, c/o BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
Nat Chem. 2010 Oct;2(10):853-7. doi: 10.1038/nchem.768. Epub 2010 Aug 8.
Aqueous ions are central to catalysis and biological function and play an important role in radiation biology as sources of damage-inducing electrons. Detailed knowledge of solute-solvent interactions is therefore crucial. For transition-metal ions, soft X-ray L-edge spectroscopy allows access to d orbitals, which are involved in chemical bonding. Using this technique, we show that the fluorescence-yield spectra of aqueous ionic species exhibit additional features compared with those of non-aqueous solvents. Some features dip below the fluorescence background of the solvent and this is rationalized by the competition between the fluorescence yields of the solute and solvent species, and between the solute radiative (fluorescence) and non-radiative channels; in particular, electron transfer to the water molecules. This method allows us to determine the nature, directionality and timescale of the electron transfer. Remarkably, we observe such features even for fully ligated metal atoms, which indicates a direct interaction with the water molecules.
水合离子是催化和生物功能的核心，作为诱导电子损伤的电子源，在辐射生物学中起着重要作用。因此，详细了解溶剂-溶质相互作用至关重要。对于过渡金属离子，软 X 射线 L 边谱学可用于研究涉及化学键的 d 轨道。我们利用该技术表明，与非水溶剂相比，水合离子物种的荧光产率光谱表现出更多的特征。一些特征低于溶剂荧光背景，这可以通过溶质和溶剂物种的荧光产率之间以及溶质辐射（荧光）和非辐射通道之间的竞争来合理化；特别是，电子转移到水分子。该方法使我们能够确定电子转移的性质、方向性和时标。值得注意的是，即使对于完全配位的金属原子，我们也观察到了这样的特征，这表明其与水分子存在直接相互作用。
