CAS: Structure, Bonding and Mechanism in Iron-Catalyzed C-H Functionalization

University Of Rochester, Rochester NY

Investigators

Abstract

The development of sustainable, more efficient and selective catalysis remains one of the key fundamental research goals in chemistry. Towards this goal, iron catalysts that can directly transform carbon-hydrogen (C-H) bonds into new chemical bonds of interest is a particularly attractive method, both in terms of reaction efficiency as well as the wide availability, low cost and minimal toxicity of iron. Unfortunately, the development of such reactions is currently hindered by the lack of fundamental understanding of the catalytic species and reaction steps involved. In this project, Dr. Neidig from the University of Rochester is identifying which iron species are responsible for effective catalysis, how these species react to form the desired reaction products, and how catalyst structure and bonding relates to reactivity. The fundamental insight obtained in these studies will serve to facilitate and inspire the rational design and development of iron catalysts with improved performance in C-H functionalization in advanced chemical manufacturing. Dr. Neidig is actively engaged in several outreach activities that promote student training and engagement in science, technology and mathematics disciplines. These activities, which include research opportunities for both local community college and underrepresented high school students as well, are aimed at encouraging the next generation of students to pursue careers in science. Dr. Neidig of the University of Rochester, with funding from the Chemical Structure, Dynamics and Mechanisms-B Program of the Chemistry Division, is developing a detailed fundamental understanding into the active catalyst species and underlying molecular mechanisms of catalysis in iron-catalyzed C-H functionalization. This insight is achieved through an approach combining multiple inorganic spectroscopies (magnetic circular dichroism, Mössbauer, electron paramagnetic resonance, and resonance Raman), density functional theory, synthesis and kinetic and reaction studies. Specific studies include defining the details of the iron(II)/iron(III)/iron(I) mechanistic cycle and its broader role across additional C-H functionalization reactions, as well as evaluating proposed iron(III)/iron(I) and low-valent iron reaction manifolds for C-H functionalization in order to identify and define alternative mechanistic frameworks for targeted, rational methods development. Further studies are investigating the reduced iron-phosphine complexes, reaction intermediates and mechanism enabling effective C-H functionalization catalysis in the absence of directing groups, including key ligand properties that enable effective C-H functionalization. Dr. Neidig is actively engaged in STEM outreach research programs with local community college students and faculty as well as underrepresented high school students in the Rochester City School District, in support of the broader impacts of this project. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.