Using a modified quadrupole ion trap mass spectrometer, a series of metal complex ions have been reacted with acetonitrile in the gas phase. Careful control of the coordination number and the type of coordinating functionality in diethylenetriamine-substituted ligands enable the effects of the coordination sphere on metal complex reactivity to be examined. The association reaction kinetics of acetonitrile with these pentacoordinate complexes are followed in order to obtain information about the starting complexes and the reaction dynamics. The kinetics and thermodynamics of acetonitrile addition to the metal complex ions are strongly affected by the chemical environment around the metal center such that significant differences in reactivity are observed for Co(II) and Cu(II) complexes with various coordination spheres. When thiophene, furan, or benzene moieties are present in the coordination sphere of the complex, addition of two acetonitrile molecules is readily observed. In contrast, ligands with better sigma donors react mainly to add one acetonitrile molecule. Among the ligands with good sigma donors, a clear trend in reactivity is observed in which complexes with nitrogen-containing ligands are the least reactive, sulfur-containing complexes are more reactive, and oxygen-containing complexes are the most reactive. In general, equilibrium and reaction rate constants seem to be consistent with the hard and soft acid and base (HSAB) principle. Interestingly, the presence of certain groups (e.g., pyridine and imidazole) in the coordination sphere clearly can change the acid character of the metal as seen by their effect on the binding properties of other functional groups in the same ligand. Finally, we conclude that because complexes with different coordination spheres react to noticeably different extents, ion-molecule (I-M) reactions may be potentially useful for obtaining coordination structure information for transition metal complexes.

中文翻译：

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过渡金属配合物的气相离子分子反应：不同配位体对配合物反应性的影响。

使用改进的四极离子阱质谱仪，一系列金属络合物离子已与乙腈在气相中反应。仔细控制二亚乙基三胺取代的配体中的配位数和配位官能团的类型可以检查配位球对金属络合物反应性的影响。遵循乙腈与这些五配位配合物的缔合反应动力学，以获取有关起始配合物和反应动力学的信息。乙腈添加到金属络合物离子中的动力学和热力学受到金属中心周围化学环境的强烈影响，因此对于具有各种配位球的Co（II）和Cu（II）络合物观察到反应性的显着差异。当噻吩，呋喃，如果在配合物的配位域中存在苯乙部分或苯部分，则很容易观察到添加了两个乙腈分子。相反，具有更好σ供体的配体主要反应以添加一个乙腈分子。在具有良好sigma供体的配体中，观察到明显的反应趋势，其中与含氮配体的配合物反应性最低，含硫配合物反应性最高，而含氧配合物反应性最高。通常，平衡和反应速率常数似乎与硬酸和软酸和碱（HSAB）原理一致。有趣的是，某些群体的存在（例如，吡啶和咪唑在配位域中显然可以改变金属的酸性质，如它们对相同配体中其他官能团的结合性质的影响所见。最后，我们得出结论，由于具有不同配位球的配合物的反应程度明显不同，因此离子分子（IM）反应对于获得过渡金属配合物的配位结构信息可能很有用。