Research Projects

Complexes of precious metals such as Rh, Ir, Pt, Pd, and Ru have historically played the central role in enabling a wide array of high-value and mechanistically diverse organic transformations. However, the scarcity, high cost, and geopolitical instability associated with the supply of these precious metals are increasingly limiting their long-term viability in both academic and industrial research portfolio. In contrast, the 1st-row transition metals and main group elements, owing to their earth abundance and lower cost, present a more sustainable and economically attractive alternative. However, replicating the efficiency, activity, and selectivity of precious metal derived systems with these non-precious metals remained a critical scientific challenge. Addressing this challenge requires innovative approaches for the catalyst design and one promising strategy involves the development of tailored ancillary ligands capable of substantially tuning the electronic and steric environment around the metal center. In this context, “actor ligands” are of special interest as they can actively participate along with the metal ions in key bond breaking/making steps to achieve synergistic reactivity, which may offer a compelling pathway towards unlocking the full catalytic potential of earth-abundant metals-based catalysts. Accordingly, the central theme of this proposal is to develop intelligently designed earth-abundant metal-based catalysts for the challenging organic transformations, e.g. C–F bond and CO₂ activation with the ultimate goal of converting these substrates into synthetically and industrially valuable molecules. To achieve this, we herein propose the strategic design and development of diversified functionalized azolium salts, as precursors to N-heterocyclic carbenes (NHCs), that are capable of modulating the electronic and steric environment around the non-precious metal centers through synergistic metal–ligand interactions. Accordingly, a broad range of C2-functionalized azolium salts incorporating diverse azolium moieties and redox-active (thio)amide, carbodiimide groups, each offering distinct structural attributes to enable precise control over metal reactivity, will be synthesized and used for complexation with different main group (e.g. Mg, Zn, Ge) elements. A complementary objective of the proposal involves the synthesis of strategically designed and tunable bifunctional NHC ligands that are tailored for the 1st-row transition metals such as Fe, Co, Mn. These ligand frameworks integrate the inherent robustness and strong σ-donor properties of NHCs with different donor functionalities (e.g. amine, amide, benzimidazole), providing opportunities for cooperative reactivity and hence, new catalytic protocols that are inaccessible to non-functional NHC based systems. Following the synthesis and characterization of the proposed complexes, they will be systematically evaluated in two strategically important and distinct areas: (i) inert C–F bond activation via radical-pathways, enabling the formation of diverse C–heteroatom bonds, and (ii) the activation and valorization of CO₂ through cooperative catalysis, with the aim of accessing valuable products. We expect that these proposed catalytic processes will also enable access to diverse bioactive molecular scaffolds to showcase their broader synthetic utility. Finally, detailed mechanistic probes of these catalytic endeavor via combination of experimental (various control experiments to understand the key catalytic intermediates) and theoretical (DFT studies) approaches will be undertaken to comprehend initially the stochiometric reactions followed by possible catalytic pathways. Moreover, efforts will also be directed toward the heterogenization of these catalyst systems to enhance their operational stability, reusability, and overall sustainability contributing to the development of environment friendly catalyst systems.