With the support of the Inorganic, Bioinorganic and Organometallic Chemistry Program, Professor David R. McMillin, of the Department of Chemistry at Purdue University proposes the development of synthetic methods to form new cationic porphyrin ligands that are optimized to intercalate into B-form DNA without steric strain. These porphyrins and their platinum complexes will serve as chromophoric and emissive probes for binding studies where the steric, electronic and coulombic forces of DNA binding interactions are studied in the ground and excited states via absorption and emission spectroscopies as well as circular dichroism studies. Competitive binding studies will identify systems selective for DNA hairpins and quadruplexes while exploitation of the novel emission quenching mechanisms will yield important information about the adducts formed. This grant will provide a deeper understanding of host-guest interactions using novel, rationally derived metalloporphyrins. Professor McMillin contributes to the recruitment of underrepresented minorities through his work as a Visiting Research Fellow in South Africa. Several student researchers from South Africa have joined his research group, enhancing the international experience of U.S. students.