One-Dimensional Conjugated Materials

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The Organic and Macromolecular Chemistry Program in the Chemistry Division at the National Science Foundation supports Professor Nancy Goroff of SUNY Stony Brook who will seek effective routes from one-dimensional conjugated materials (e.g., polyynes) to graphitic nanostructures. The first experiments will center on the pseudo-1-dimensional polymer poly(diiododiacetylene), or PIDA. PIDA, recently prepared in the Goroff lab, is the first reported ordered polydiacetylene with only single-atom side groups. The simplicity of the PIDA structure allows the individual polymer strands to aggregate in much greater proximity than other well studied conjugated materials. The proposed research will include studies of PIDA co-crystals and aggregates, including conductivity, magnetoresistivity, optical absorptions and the chemistry that transforms PIDA into new materials. In addition, preliminary results suggest that aggregates of one-dimensional conjugated systems with limited side groups may be uniquely facile graphitization substrates. Professor Goroff will therefore examine aggregates of polyyne rods themselves, as sources of graphitic nano-wires. Polyynes containing 3-6 adjacent triple bonds and a diverse selection of side groups will be synthesized. The aggregation behavior of each of these polyynes will be examined, as well as their polymerization behavior. Methods will be sought for making well-defined ordered materials, with complete characterization of the products' structural, optical, electronic, and chemical properties.Research by Professor Goroff offers new methods for preparing conjugated materials with unique structures. Because of their electronic and optical properties, these materials will have applications as semi-conductors and as non-linear optical absorbers. In addition to the direct impact of the research, the proposed work will offer other benefits. A major component of this proposal involves collaborative research. The proposed projects bring together scientists from many different fields, each with different expertise and research focus, increasing communication across disciplinary boundaries. The proposed research also offers significant educational benefits. The graduate students and undergraduates supported by this grant will gain experience in modern organic synthesis, computational modeling, spectroscopy, and polymer characterization methods. Professor Goroff also participates in outreach activities, including activities in the local elementary and junior high schools. For example, she recently created, with a colleague, a hands-on workshop on the Chemistry of Perfumes, which was held for three classes of 21 students each as part of a local elementary school Career Lab Day, and will be repeated in the coming years. In addition, she has developed a freshman seminar course for 20 students on the Chemistry of Cooking. These activities are designed to attract students to chemistry who might otherwise not consider chemistry as a career.