Gas-Phase Studies of Organic Sigma-type Polyradicals

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Reactivity studies on organic bi- and polyradicals are hindered by their high reactivity and short lifetime in solution. Only little is known, for example, about the factors that control the chemical properties of many carbon-centered radicals, and nothing is known about the chemical properties of related tri- and tetraradicals. However, information on the factors that control the chemical properties of these species is highly desirable since it may allow one to "tune" their reactivity by varying structural details and hence design polyradicals with tailored properties. The ability to do this is expected to impact many fields, including organic synthesis, materials science (e.g., organic magnets), and drug development. In the past, PI and her students have studied the reactivity of gaseous mono- and biradicals by using Fourier-transform ion cyclotron resonance mass spectrometers (FT-ICR), a flowing afterglow quadrupole-octapole-quadrupole apparatus, and most recently, a linear quadrupole ion trap. These studies have revealed several important reactivity controlling factors that can be used to "tune" the reactivity of these species. This project will extend these studies to analogous tri- and tetraradicals whose reactivity is nearly entirely unexplored. The properties of several isomeric and differently substituted tri- and tetraradicals will be explored by experimental studies on their reactivity and by computational studies on their geometries and electronic structures. More than 20 graduate and at least five undergraduate students will carry out all aspects of the research, and disseminate the results under the PI's supervision. About half of the participating students are female and/or belong to underrepresented minorities. Further, mass spectrometry will be introduced to Purdue's College of Science Van that delivers research grade instruments to high and middle schools throughout central Indiana. The proposed research will lead to the training of a large number of ethnically diverse, highly qualified science Ph.D.'s.