My group’s research is broadly focused on synthetic, supramolecular, analytical, and materials chemistry. We are interested in a spectrum of topics with an emphasis on the synthesis and construction of functional assemblies. Molecular recognition pervades a great deal of our research. Chemosensors require recognition elements to discriminate chemical signals. Electronic polymers are one of the areas that our group is well known for having made many innovations. We are constantly developing new electronic structures, properties, and uses for these materials. Recently we have launched an effort to create functionalized carbon nanotubes and graphenes. We have advanced new chemical methods for their functionalization and utilization in electrocatalysis and chemical and radiation sensing. In the area of liquid crystals we make use of molecular complimentarity and receptor-ligand interactions to provide novel organizations.
Student and postdoctoral researchers in my group are exposed to a broad range of topics including synthetic chemistry, organic chemistry, polymer chemistry, inorganic chemistry, organometallic chemistry, electro-chemistry, photo-chemistry, and liquid crystal science. The subject areas are briefly summarized here and more can be learned by visiting my group’s home page.
- Chemosensors are molecule-based devices that are designed and synthesized to detect a specific chemical signal. Our chemosensory research is directed at harnessing the unique properties of conjugated organic polymers (molecular wires). We demonstrated some years ago that “wiring molecular recognition sites in series” leads to ultra-high sensitivity and that this approach has universal applicability for the amplification of chemosensory responses. The principles developed by our group can amplify chemosensory signals by many orders of magnitude. Our sensor principles are now broadly practiced by many research groups around the world and are the basis of a number or emerging sensor technologies. Nonetheless, there are still many basic scientific principles to be determined. Our continuing work is focused upon the design, synthesis, and investigation of novel electronic polymers, graphenes, carbon nanotubes, and receptors.
- We are developing new classes of Metal Containing Conductive Polymers and Nano-Carbon Composites that contain transition metal centers, for catalytic and recognition functions. Our group has succeeded in making the most conductive transition metal hybrid structures and has demonstrated that these materials have important new transport characteristics and properties. We have also used covalent assemblies of carbon nanotubes and transition metals to give materials with high electrochemical catalytic activity.
- Liquid crystals are undergoing a scientific renaissance! New liquid crystalline phases are being frequently discovered and supramolecular science is making extensive use of liquid crystals as a method for self-assembly. Our interests are broad and include the design and discovery of new classes of liquid crystals, investigations of liquid crystals with high chirality, demonstrations of novel electro-optical effects, development of molecular recognition approaches to liquid crystals, and investigations of new types of polymer/liquid crystal composites. One very useful method for the discovery of novel phases is to assemble liquid crystals from molecules with unusual shapes. Our efforts are focused on transition metal complexes, highly unsaturated organic compounds, and polymers that offer special optical, electronic, and structural properties.
- The ability to organize molecules into complex supramolecular structures is a critical foundation for the development of future molecular device technologies. We are applying molecular recognition principles to the formation of new polymers architectures and organizations.
- Dynamic nuclear polarization is a method that can provide orders of magnitude enhancements in NMR. In collaboration with Professor Griffin (MIT Chemistry) we have developed biradical systems that allow for efficient spin polarization transfer from electrons to nuclei. Our compounds provide record-level enhancements and are being used widely by the NMR community. Ongoing efforts are to create ever more efficient biradicals for the hyperpolarization of nuclei and to extend these methods to MRI imaging.
- Synthesis underpins all aspects of our program and over the years we have developed new reaction methodologies. Areas of specific interest are methods to create polycyclic aromatic systems, novel chain growth polymerizations to create polyaromatic structures, directed annulations, complex block copolymers, and novel methodology for the functionalization of nanocarbon materials.