One of the most important advances in inorganic chemistry over the last half century was the discovery of stable compounds containing low coordinate heavy main group elements, including cations and multiply bonded species. The spectroscopic and structural characterization of these unsaturated molecules has profoundly influenced our understanding of structure and bonding. Of equal importance, multiply bonded compounds of the heavy main group elements have proven to be powerful building blocks in organometallic/inorganic synthesis just as alkenes and alkynes are in organic synthesis. An impressive array of previously inaccessible compounds, particularly ring systems, has been made from metallenes(ynes) over the past 25 years. As a sign of the maturation of the field, applications of this chemistry are now being explored; for example, the use of the highly regiospecific cycloaddition reactions of silenes (R2Si=CR2) in organic synthesis, the use of silenes, germenes (R2Ge=CR2) and phosphaalkenes (RP=CR2) in the synthesis of novel inorganic polymers, the use of silyl cations to hydrodefluorinate fluoroalkanes, and the addition of unsaturated organic molcules to the silicon (or germanium) dimers (Si=Si) on reconstructed Si(Ge)(100) 2 x 1 surfaces as a means to modify the interfacial and electronic characteristics of the material.
Our research program explores this exciting area of chemistry with a focus on Group 14 compounds in the following three general areas:
Synthesis: We continue to seek out new bonding paradigms and to challenge our synthetic acumen by exploring the synthesis of new, unprecedented molecules. Such molecules enhance our understanding of fundamental chemistry and are necessary for future innovations.
Mechanism: As is well-recognized in carbon chemistry, to achieve the full potential of unsaturated heavier main group compounds, it is critical to have a firm understanding of their reaction mechanisms. We have developed innovative mechanistic probes for the study of the cycloaddition reactions of these compounds.
Applications: We have recently discovered a new approach to polysilenes and polygermenes, polymers with an alternating silicon (or germanium) carbon backbone. We continue to explore the chemistry and applications of this novel class of polymers.