G.A. Razuvaev Institute of Organometallic Chemistry of the Russian Academy of Sciences, 49 Tropinin St., 603950 Nizhny Novgorod, Russia.
Institute of Atomic and Molecular Sciences, Academia Sinica, 1 Section 4, Roosevelt Road, Taipei 10617, Taiwan.
Molecules. 2022 Sep 22;27(19):6226. doi: 10.3390/molecules27196226.
Metallocenes represent one of the most important classes of organometallics with wide prospects for practical use in various fields of chemistry, materials science, molecular electronics, and biomedicine. Many applications of these metal complexes are based on their ability to form molecular ions. We report the first results concerning the changes in the molecular and electronic structure of decamethylmanganocene, CpMn, upon ionization provided by the high-resolution mass-analyzed threshold ionization (MATI) spectroscopy supported by DFT calculations. The precise ionization energy of CpMn is determined as 5.349 ± 0.001 eV. The DFT modeling of the MATI spectrum shows that the main structural deformations accompanying the detachment of an electron consist in the elongation of the Mn-C bonds and a change in the Me out-of-plane bending angles. Surprisingly, the DFT calculations predict that most of the reduction in electron density (ED) upon ionization is associated with the hydrogen atoms of the substituents, despite the metal character of the ionized orbital. However, the ED difference isosurfaces reveal a complex mechanism of the charge redistribution involving also the carbon atoms of the molecule.
茂金属是最重要的有机金属化合物之一，在化学、材料科学、分子电子学和生物医学等各个领域具有广泛的应用前景。这些金属配合物的许多应用都是基于它们形成分子离子的能力。我们报告了首例有关 CpMn（十甲基二茂锰）分子和电子结构在高分辨质量分析阈电离（MATI）光谱支持下通过 DFT 计算发生变化的结果。CpMn 的精确电离能确定为 5.349±0.001eV。MATI 光谱的 DFT 模拟表明，伴随着电子脱离的主要结构变形包括 Mn-C 键的伸长和 Me 面外弯曲角度的变化。令人惊讶的是，尽管离子化轨道具有金属特性，但 DFT 计算预测，电子密度（ED）在电离时的大部分减少与取代基的氢原子有关。然而，ED 差分等密度面揭示了涉及分子碳原子的电荷重新分布的复杂机制。
