Electrospray ionization mass spectrometry (ESI-MS) is a valuable and frequently used analytical technique across nearly all branches of chemistry, and has recently seen increasing use in the study of metal–ligand solution equilibria. Despite its prevalence, the method by which ESI produces gas-phase ions from solutions containing metal–ligand complexes is not fully understood, with recent reports showing significant changes to solution equilibria during ESI analysis. This study examines perturbations to the formation kinetics of metal–ligand complexes during the ESI process, showing how quickly new equilibria – reflective of the ionization process and not solution – can be established. Electrospray ionization mass spectrometry (ESI-MS) and ion mobility spectrometry (IMS) are used to examine the well studied Lu-DOTA (1,4,7,10-tetraazacyclododecane-N,N′,N′′,N′′′-tetraacetic acid) complexation reaction, with collision cross section modeling based on density functional theory (DFT) optimized structures used to aid in the interpretation of the ion mobility results. The electrospray process was found to significantly accelerate the formation kinetics, increasing the formation rate constant by more than an order of magnitude over its previously determined solution-phase value.

中文翻译：

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电喷雾电离加速金属-配体的络合动力学

电喷雾电离质谱法（ESI-MS）是几乎所有化学分支中都很有价值且经常使用的分析技术，并且最近发现在金属-配体溶液平衡研究中的使用越来越多。尽管ESI盛行，但尚不完全了解ESI从包含金属-配体络合物的溶液中产生气相离子的方法，最近的报道显示在ESI分析过程中溶液平衡发生了重大变化。这项研究检查了在ESI过程中对金属-配体络合物形成动力学的扰动，显示了可以很快建立新的平衡-反映了电离过程而不是溶液-。电喷雾电离质谱（ESI-MS）和离子迁移谱（IMS）用于检查经过充分研究的Lu-DOTA（1,4,7,10-四氮杂环十二烷-N，N '，N ''，N '''-四乙酸）络合反应，具有基于密度泛函理论（DFT）优化结构的碰撞截面建模，可用于解释离子迁移率结果。发现电喷雾过程显着加速了形成动力学，使形成速率常数比其先前确定的固溶相值增加了一个数量级以上。