Exploiting Zwitterionic late metal complexes in addressing challenging bond activation chemistry

Chemical research will figure prominently in addressing a number of societal challenges, including: (a) the development of environmentally friendly methods for the conversion of abundant raw materials into value-added products, including pharmaceuticals; (b) the more efficient utilization of our diminishing hydrocarbon resources; and (c) the identification of recyclable materials for the controlled release of combustible molecules such as hydrogen. One difficulty common to these challenges is the selective breaking and reforming unreactive substrate E-H bonds (E = H, C, N, P, etc.). When appropriately constructed, transition metal complexes are able to activate (i.e. induce reactivity in) typically unreactive molecular fragments, including E-H bonds. While significant advances have been made in metal-mediated single E-H bond activation catalysis, related processes involving the activation of two E-H bonds within a substrate (double E-H bond activation) are comparatively few. Given the central role that double E-H bond activation could play in addressing the reactivity challenges outlined above, the design of metal catalysts that can mediated double E-H bond activation reactions represents an important, yet formidable, challenge.My research group has recently developed a new class of zwitterionic catalyst complexes (some of which are now commercially available through Strem Chemicals) that mediate catalytic double E-H bond activation processes. In the course of our investigations, we became intrigued by the possibility that the unique and aggressive reactivity of these zwitterionic catalysts might be attributable to cooperative metal-indenide substrate activation. This proposal seeks to build upon our exciting discoveries, with emphasis on the development of novel cooperative catalysts featuring donor-substituted indenide ligation that can promote challenging and synthetically useful double E-H bond activation chemistry in a manner that cannot be achieved by use of more conventional catalyst systems.