Mechanistic Probes in Main Group Chemistry Employing Highly Reactive Species Containing Electron-Deficient Atoms

化学结构，动力学和机制计划（CSDM）支持圣刘易斯的华盛顿大学的Peter Gaspar教授在较重元素的共价键研究中使用物理有机化学概念。现代有机合成和材料化学用于研究包含元素周期表第一行以下主族元素的分子。 无论是天然产物、电子材料、药物输送系统的新立体选择性路线，还是硅基材料的生物启发纳米纤维，这些努力的成功都取决于通过理解重元素键的形成和断裂来发展主族机械化学。 拟议的研究协同结合离子化学，气相和液相化学反应性的研究，和计算建模质谱阐明。 该策略是研究缺电子和多键物种的结构和反应性很好地描述了有机化学的机械思想的染料元素类似物。 母体物种，如卡宾和氮烯，以这样一种独特的方式反应，机械变化可以很容易地在其较重的类似物中被识别出来。 观察到的变化不仅将拓宽我们的机理思想，而且还将导致发现新的合成有用的试剂。 在待研究的物种中，有一个极端缺电子的离子和分子家族，它们的外壳中只有四个电子。 它们有可能参与同时形成三个新键的反应，这是以前从未观察到的过程，也很少有人提出。 它们代表了具有相当大的合成兴趣的周环反应的三维延伸。 这项工作的更广泛的影响包括发现基本原理的前景，这些原理将帮助我们更好地理解共价键，它的形成和整个周期表的反应性，并利用这些知识找到有用的新化学，并制造新分子。 对于在这个项目中接受培训的同事来说，他们的经验提供了一个多样化的背景，鼓励他们发展多功能性和信心，使他们能够解决广泛的问题并开展多样化的职业生涯。 在他的职业生涯中，加斯帕一直参与在研究生，本科，博士后和高中水平的代表性不足的群体的培训。 其中包括被授予罗兹学者、辉瑞夏季研究员以及NSF和NIH研究生奖学金获得者的本科生。 加斯帕集团的研究生在竞争博士后奖学金方面取得了相当大的成功，博士后在工业、研究机构和学术界都获得了很好的任命。

The Chemical Structure, Dynamics and Mechanism Program (CSDM) supports Professor Peter Gaspar of Washington University in Saint Louis to use physical organic chemistry concepts in the study of covalent bonds in the heavier elements. Modern organic synthesis and materials chemistry are used to study molecules incorporating main group elements below the first row of the periodic table. Whether it is new stereoselective routes to natural products, electronic materials, drug delivery systems, or bio-inspired nanofabrication of silicon-based materials - success in these endeavors depends on the evolution of main-group mechanistic chemistry through the understanding of the making and breaking of bonds to heavier elements. The proposed research synergistically combines mass spectrometric elucidation of ion chemistry, gas- and solution-phase study of chemical reactivity, and computational modeling. The strategy is to study heavier-element analogs of electron-deficient and multiply bonded species whose structure and reactivity are well described by the mechanistic ideas of organic chemistry. The parent species, such as carbenes and nitrenes, react in such a distinctive manner that mechanistic changes can readily be recognized in their heavier analogs. The observed changes will not only broaden our mechanistic ideas, but also lead to the discovery of new synthetically useful reagents. Among the species to be studied is a family of extremely electron-deficient ions and molecules with only four electrons in their outer shells. These have the potential for participating in reactions that form three new bonds simultaneously, processes never previously observed and rarely suggested. They represent a three-dimensional extension of pericyclic reactions with considerable synthetic interest. Included in the broader impacts of this work are the prospects for discovery of basic principles that will help us to better understand the covalent bond, its formation and reactivity throughout the periodic table, and to use that knowledge to find useful, new chemistry, and to make new molecules. For the coworkers trained on this project, their experience provides a diverse background, encouraging them to develop a versatility and confidence that prepares them to tackle a broad range of problems and launch diverse careers. Throughout his career, Gaspar has been involved in the training of under-represented groups at the graduate, undergraduate, postdoctoral and high school levels. These have included undergraduates honored as Rhodes Scholars, Pfizer Summer Research Fellows, and as winners of NSF and NIH graduate fellowships. Graduate students in the Gaspar group have had considerable success in competing for postdoctoral fellowships, and postdoctorals have secured excellent appointments in industry, research institutes, and academia.