Development of cryogenic ion spectroscopy as a structural tool for complex ions extracted from solution and spectroscopic characterization of non-covalent interactions

在这项由化学系化学结构、动力学和机制计划资助的奖项中，耶鲁大学的Mark A.Johnson教授将继续他的振动光谱与低温质谱学的结合，创造出一种新的、普遍适用的化学分析结构探测器，分辨率和灵敏度都有显著提高。这一发展利用了最新的技术进步，允许从溶液中提取越来越复杂的物种，在10K附近冻结成定义良好的结构，进行质量选择，然后用振动、电子和(对于阴离子)光电子能谱进行表征。这些气相研究最重要的方面是，因为物种被淬火成最小的热波动组态，所以恢复的带状图案比在凝聚介质中观察到的要尖锐得多。约翰逊的计划将扩展和扩大低温振动光谱的用途，以阐明生物聚合物折叠结构的特殊氢键给体-受体对，以及那些在非共价键合的主客体络合物中发挥作用的结构。将特别强调识别产生底物分子与仿生肽催化剂高度选择性对接的场景。这项研究的一个重要方面将是阐明在气相中获得的构象与在溶液中发现的构象之间的关系，这将通过遵循离子结构对气相团簇中保留的溶剂分子数量的依赖来实现。由于这些测量是使用专门为这一应用而构建的方法进行的，他的计划致力于改进实验方法，包括温度控制和分离物种的微溶剂化。约翰逊的计划直接将物理化学学生与合成同事解决的直接挑战联系起来，从而培养出具有全面技能的新一代科学家，他们很好地以化学科学为中心。他的计划为化学分析的一个新兴分支奠定了坚实的基础，在该分支中，复杂的系统受到超分子的结构表征的影响。这种方法的通用性非常适合年轻研究人员和老牌同事的参与，用令人兴奋和强大的新方法来探索化学结构。

In this award funded by the Chemical Structure, Dynamics and Mechanisms Program of the Division of Chemistry, Professor Mark A. Johnson of Yale University will continue his integration of vibrational spectroscopy with cryogenic mass spectrometry to create a new, generally applicable structural probe for chemical analysis with dramatically enhanced resolution and sensitivity. This development exploits very recent technological advances that allow increasingly complex species to be extracted from solution, frozen into well-defined structures near 10 K, mass-selected, and then characterized with vibrational, electronic and (in the case of anions) photoelectron spectroscopies. The most important aspect of these gas-phase studies is that, because species are quenched into configurations with minimal thermal fluctuations, much sharper band patterns are recovered than are observed in condensed media. Johnson's program will extend and expand the utility of cryogenic vibrational spectroscopy to elucidate the particular H-bond donor-acceptor pairs of folded structures of biopolymers as well as those at play in non-covalently bonded host-guest complexes. Special emphasis will be placed on identifying scenarios which yield highly selective docking of substrate molecules to biomimetic peptide catalysts. An important aspect of the study will be to elucidate the relationship between the conformations obtained in the gas phase and those found in solution, which will be accomplished by following the dependence of ion structure on the number of solvent molecules retained in the gas-phase cluster. Because these measurements are carried out using methods specifically built for this application, his program dedicates significant effort toward refinement of the experimental approach, including temperature control and micro-solvation of the isolated species.Johnson's program directly interfaces physical chemistry students with immediate challenges addressed by synthetic colleagues, and thus prepares a new generation of scientists with a versatile skill set, well centered in the chemical sciences. His program contributes to the strong foundation of an emerging branch of chemical analysis where complex systems are subjected to structural characterization in the ansatz of a supermolecule. The generality of the approach is ideally suited to engage young researchers and established colleagues alike, with exciting and powerful new ways to explore chemical structure.