NSF Young Investigator: Gas-Phase Host-Guest Chemistry and Detection of Antibiotics

将进行两个领域的研究：(1)气相主客体化学和(2)抗生素的激光解吸/选择性离子-分子反应。在第一个主题中，将通过应用质谱学技术来研究模型体系的无溶剂主客体化学的各个方面。模型体系包括一系列大小选择性的主体(即冠醚和相关的大环和非环类似物)和客体(即各种金属离子、卤化物离子或氨离子)。大环主客体络合物将在气相中通过双分子反应形成，然后用碰撞诱导解离技术计算其结构和结合能。在第二个主题中，将发展四极离子陷阱中的激光解吸/选择性离子-分子反应方法用于抗生素，特别是那些受金属离子结合控制活性的抗生素。通过使用选择性的双分子反应对感兴趣的生物分子进行化学修饰，将根据修饰后的分子如何解离以及分子是否经历结构特定的反应来获得结构细节。来自有机动力学项目的这笔资金支持德克萨斯大学奥斯汀分校的詹妮弗·S·布罗德贝特教授的研究。主体分子和客体分子或离子之间的络合作用将在气相中进行研究，这对理解许多生物过程很重要。这将允许在没有溶剂贡献的情况下评估主人和客人之间的结合力。通过这种方法，分子识别中的主要作用力将被推导出来。在另一个项目中，将开发技术来表征抗生素分子，特别是那些其活性由金属离子结合决定的分子。将使用质谱仪和特殊技术在气相中进行表征。

Two areas of research will be pursued: (1) Host-guest chemistry in the gas-phase and (2) Laser desorption/selective ion-molecule reactions of antibiotics. In the first topic, a variety of aspects of solvent-free host-guest chemistry of model systems will be investigated by application of mass spectrometric techniques. The model systems include an array of size-selective hosts (i.e., crown ethers and related macrocycles and acyclic analogs) and guests (i.e., various metal ions, halide ions, or ammonium ions). The macrocyclic host-guest complexes will be formed via bimolecular reactions in the gas-phase, then their structures and binding energies will be evaluated by collision-induced dissociation techniques. In the second topic, laser desorption/selective ion-molecule reaction methodology in a quadrapole ion trap will be developed for antibiotics, especially those whose activities are controlled by metal ion binding. Through the use of selective bimolecular reactions that chemically modify the biological molecules of interest, structural details will be obtained based on how the modified molecules dissociate and if the molecules undergo structurally-specific reactions. %%% This grant from the Organic Dynamics Program supports the research of Professor Jennifer S. Brodbelt at the University of Texas, Austin. Complexation between a host molecule and a guest molecule or ion, which is important to understanding many biological processes, will be studied in the gas-phase. This will allow for an evaluation of the binding forces between the host and guest without solvent contributions. By this means, the primary forces in this molecular recognition will be deduced. In another project, techniques will be developed to characterized antibiotic molecules, especially those whose activities are determined by binding of metal ions. The characterization will be done in the gas-phase with the use of a mass spectrometer and special techniques.