Cryogenic Ion Spectroscopy Studies of Ion-Receptor Interactions in Water Soluble Molecular Recognition Complexes and Their Hydrated Clusters

在这个由化学结构，动力学和机制资助的项目中，J. Mathias Weber教授和他的团队将研究带电原子和分子（离子）如何在一个称为分子识别的过程中与旨在捕获它们的分子（受体）结合，以及水分子的存在如何改变这种识别过程。离子受体可用于测量和控制许多化学环境中的离子浓度，从一组抗生素到传感器和材料科学。离子识别还对有关食品和水源的重要问题产生影响，例如公共供水的安全性，或来自工业和农业来源的某些类型的分子离子的污染。 Weber教授计划开展与他的科学研究相关的推广和教育活动，包括开发用于高等本科化学主题教学的模拟，这将提供宝贵的资源，特别是对于无法参加校园动手活动的学生。该项目侧重于溶剂在受体-离子相互作用中的作用，这是理解溶液中分子识别的最困难的问题之一。解决方案的复杂性提出了许多障碍，调查的离子，受体和溶剂的相互作用，从在相同的样品中存在多个物种具有相似的响应实验探针，大部分溶剂掩蔽关键的光谱特征，溶剂分子的波动数量与主客体对相互作用。许多离子-受体复合物的带电性质允许选择性制备和质谱分离相关物质，包括它们的水合簇，并规避上述障碍。Weber小组采用低温离子光谱学与电喷雾电离质谱法相结合来测量由阴离子和结合这些离子的合成受体组成的离子络合物的红外光谱。这些光谱和伴随的量子化学计算将产生关于负离子的结构和控制分子识别的分子间力的信息。此外，韦伯小组将表征这些复合物与水分子的相互作用。在这项工作中获得的知识将有助于开发合成离子受体设计的预测方法。这项工作的预期结果产生的更广泛的影响有可能改变科学家对离子分子识别的看法，这是化学科学的前沿。开发解决离子在环境和技术场景中的影响的应用程序，包括食物和水的关系，可以产生重大的社会影响。 韦伯教授还将继续推广和教育工作，包括开发基于网络的模拟教学量子力学，化学动力学和spectroscopyThis奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

In this project funded by the Chemical Structure, Dynamics and Mechanisms-A program of the Chemistry Division, Professor J. Mathias Weber and his team will study how charged atoms and molecules (ions) bind to molecules designed to capture them (receptors) in a process called molecular recognition, and how the presence of water molecules changes this recognition process. Ion receptors can be used to measure and control the concentration of ions in numerous chemical contexts, ranging from a group of antibiotics to sensors and materials science. Ion recognition also has impact on important issues regarding food and water sources, such as the safety of public water supplies, or pollution with some types of molecular ions from industrial and agricultural sources. Professor Weber plans to develop outreach and educational activities related to his scientific studies, including developing simulations for use in teaching advanced undergraduate chemistry topics, which would provide a valuable resource, particularly for students who cannot participate in hands-on activities on campus.The project focuses on the role of the solvent in receptor-ion interactions, which is one of the most difficult problems for understanding molecular recognition in solutions. The complexity of solutions presents many obstacles to investigating the interplay of ion, receptor, and solvent, from the presence of multiple species in the same sample with similar responses to experimental probes, to the bulk solvent masking key spectroscopic signatures, to the fluctuating number of solvent molecules interacting with the host-guest pair. The charged nature of many ion-receptor complexes allows selective preparation and mass spectrometric isolation of relevant species, including their hydrated clusters, and circumvents the obstacles mentioned above. The Weber group employs cryogenic ion spectroscopy in concert with electrospray ionization mass spectrometry to measure the infrared spectra of ionic complexes consisting of anions and synthetic receptors binding such ions. These spectra and the accompanying quantum chemical calculations will yield information on the structures and intermolecular forces governing molecular recognition of negative ions. Additionally, the Weber group will characterize the interaction of these complexes with water molecules. The knowledge gained in this work will help in developing predictive methods for the design of synthetic ion receptors. The broader impacts from the expected outcome of this work has the potential to change the way scientists think about ion molecular recognition, which is a frontier in chemical science. The development of applications that address the impact of ions in environmental as well as technical scenarios, including the nexus of food and water, can have significant societal impact. Professor Weber will also continue outreach and educational work, including development of web-based simulations for teaching quantum mechanics, chemical kinetics, and spectroscopyThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.