LEAPS-MPS Discovery of Earth-abundant Transition-metal Catalysts for Small Molecule Functionalization and Mechanistic Insights

In this project managed by the Chemistry Division at NSF, Professor Rebeca Arevalo and her students at the University of California, Merced will perform studies that aim to explore new bond-activation strategies by Earth-abundant metal complexes and leverage this knowledge to the discovery of sustainable catalysts for the functionalization of inert bonds in small molecules. In particular, different types of C-H bonds will be targeted, which are amongst the strongest in organic molecules and require precious metals with limited Earth-abundance for its cleavage. Professor Arevalo and her students will target sustainable and green metals to achieve C-H bond functionalization and will dig into the design requirements of the complexes to be efficient. They will investigate the synthesis, characterization, and catalytic reactions of new complexes with silicon and phosphorous-containing donors. Their studies could provide valuable insights for catalyst design for the synthesis of functional molecules. This project will serve to provide underrepresented Hispanic students with experience in synthesis and characterization of air- and moisture-sensitive metal complexes and with knowledge in mechanistic studies in catalysis, as well as constitute a starting point for the creation of instructional materials and new curriculum at UC Merced. Professor Arevalo and her students will synthesize new Earth-abundant transition-metal complexes and evaluate their efficiency as homogeneous catalysts for the functionalization of inert C(sp3)-H bonds and for tandem processes involving C(sp)-H functionalization. The focus will be placed on 1st-row transition-metal complexes where two different strategies will be explored for bond activation (a) metal-centered processes and (b) metal-ligand cooperation. The functionalization of C-H bonds in inert small molecules will render access to valuable synthons for pharma industry and materials chemistry by new synthetic routes involving sustainable catalysts and feedstock starting materials that might be considered as unsuitable due to their inertness. Professor Arevalo and her students will aim to elucidate the keys for the design of catalysts efficient for C-H functionalization through mechanistic studies and rational catalyst design. Their results will contribute to increase the knowledge of the underexplored Earth-abundant transition-metal organometallic chemistry and open new avenues for the discovery of new strategies for the activation of strong bonds in organic molecules. They will use NMR, EPR and IR spectroscopy as well as single-crystal X-ray diffraction and gas chromatography to characterize the catalysts and the new functional molecules and gain insights into the cycles operative in catalysis. 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.