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

点击翻译按钮获取中文摘要

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.