RUI: An Examination of the Utility of Tris(phosphino)borates as Supporting Ligands for Rhenium(I) Dihapto-Arene Complexes

Macalester College, Saint Paul MN

Investigators

Abstract

In this project funded by the Chemical Synthesis program of the Chemistry Division, Professor Paul J. Fischer of Macalester College leads a research group of exclusively undergraduate students in designing and synthesizing new rhenium (Re) metal complexes for chemical synthesis applications. Specifically, the target Re complexes are anticipated to bind organic molecules (for example, benzene and naphthalene, inexpensive substances found in crude petroleum), and activate them toward reactions under mild conditions. The hypothesized results of these reactions include transformations of these abundant feedstock chemicals into more useful substances that require significantly more energy-intensive strategies to prepare using current methods. This project will provide a stimulating training ground in modern research methods for talented undergraduate students including women and African American students. This research program seeks to equip undergraduate students with the skills, tenacity and enthusiasm to facilitate their success in chemical research in subsequent graduate studies. This project examines the feasibility and advantages of employing tris(phosphino)borates as surrogates for hydrotris(1-pyrazolyl)borate for the preparation of pi-basic fragments with high propensity to coordinate arenes in a dihapto fashion. Thermal and photochemical syntheses are being pursued to open the completely unexplored area of tris(phosphino)borate rhenium chemistry. Special emphasis is being placed on modulating the electronic and steric environment of Re fragments of tris(phosphino)borates for optimum dearomatization of aromatic substrates. Reaction products are characterized by NMR (nuclear magnetic resonance) and IR (infra-red) spectroscopies, cyclic voltammetry and X-ray crystallography, the latter via collaboration with the University of Minnesota.