About the Seminar:
Graphene and its properties have motivated research on large polycyclic aromatic hydrocarbons (PAHs), which are basic building blocks of graphene and other carbon-rich nanostructures. Various PAHs are of interest as molecular models, synthetic precursors, and components in electronic devices, due to unique properties that result from their extended conjugation and rigidity. A central goal in this area is the synthetic manipulation of electronic properties for nanocarbon materials, by generation of well-defined dimensionalities and functionalizations. We have employed selective metal-mediated cycloadditions for extension of π systems and introduction of multiple fused rings in the synthesis of π-conjugated oligomers, polymers, and macrocycles, mainly via the reductive coupling of alkynes with a low-valent zirconocene reagent. In addition to the zirconocene coupling of alkynes, high-yielding and chemoselective [2+2+2] cycloadditions of alkynes (with an iridium catalyst) and/or [2+2+n] cycloadditions of nitriles (with titanocene) have been developed as complimentary synthetic tools for access to and elaboration of nanocarbon structures. An additional aspect to zirconocene alkyne coupling chemistry involves reversible processes that allow “Dynamic Covalent Chemistry” assembly of large structures including macrocycles and cages.
About the Speaker:
T. Don Tilley is the PMP Tech Chancellor’s Chair in Chemistry in the College of Chemistry at UC Berkeley, and is a Faculty Senior Scientist in the Catalysis Program at the Lawrence Berkeley National Laboratory (LBNL). He received his BS degree in Chemistry from UT Austin, and a PhD from Berkeley working with Richard Andersen on organolanthanide chemistry. His postdoctoral studies were conducted in the labs of Bob Grubbs and John Bercaw at Caltech, and Luigi Venanzi and Piero Pino at ETH Zürich, in a US-Swiss exchange program. In 1983 he began his independent career at the University of California, San Diego, where he was eventually promoted to Professor in 1990, and then in 1994 he accepted appointments at UC Berkeley and LBNL. He is a fellow of the American Chemical Society, the American Association for the Advancement of Science, the American Academy of Arts and Sciences, and the NAS. He has received national awards from the American Chemical Society for organometallic chemistry, silicon chemistry, and distinguished service to inorganic chemistry. International recognitions have come from Japan (JSPS Fellowship), Germany (Humboldt; Wacker Silicon Award), France (visiting Professorships), and the UK (Centenary Medal).
Dr. Tilley’s research addresses fundamental aspects of organometallic chemistry and catalysis. In an important aspect of this work, synthetic and mechanistic transition metal-silicon chemistry is investigated in pusuit of more efficient and sustainable transformations of silicon compounds, and the formation of silicon-containing polymers. Additional research in organic materials chemistry focuses on synthetic routes to conducting, semi-conducting and optically active systems with extended conjugation, and targets molecular cut-outs of important nanocarbon materials such as graphene and nanotubes. As a Faculty Senior Scientist at LBNL, he developed a program based on the molecular design and synthesis of advanced materials including complex oxides produced from tailored precursor molecules and heterogeneous, single-site catalysts. Currently, a major part of Tilley’s research program focuses on solar energy conversion, and molecular, nanostructured, and surface-attached catalysts in applications for solar–fuels technologies. Reactions of interest are water oxidation, hydrogen generation, and carbon dioxide reduction, and primary activities involve mechanistic studies of multielectron chemical transformations promoted by multimetallic assemblies.
