Hosted by: Aaron Sadow

Title: "Ligand Design with Boron and Phosphorus: From Cooperative Reactions with Transition Metals to Covalency Investigations with f-Elements"
 

Abstract

In this talk, I will describe recent efforts in the Daly Group aimed at developing boron and phosphorus ligands for two distinct projects: 1) cooperative ligand-centered reactions with transition metals, and 2) covalent metal-ligand bonding and reactivity studies with trivalent actinides and lanthanides. The first part of the presentation will focus on a class of diphosphorus ligands called TBDPhos that are derived from the triaminoborane 1,8,10,9-triazaboradecalin (TBD). We have shown how the TBD subunit is chemically reactive and can be protonated to form highly Lewis-acidic borenium ions (i.e. three-coordinate boron cations) while TBDPhos is bound to different transition metals. I will describe how this reactivity enables access to tandem, one-pot reactions using separate metal and ligand reactive sites. The second part of the presentation will focus on trivalent f-metal complexes with chelating, phosphorus-bridged borohydrides called phosphinodiboranates. I will describe how mechanochemical reactions were used to access these complexes in reproducible yields so that we could quantify the influence of metal-ligand covalency on f-metal deoligomerization reactivity in solution. I will also describe the solution synthesis and bonding analysis of the first structurally characterized Pu(III) borohydride complex. The implications of these results with respect to long-standing hypotheses about the suspected role of covalency in effective nuclear waste separations will be discussed.