Research Projects

One of the biggest challenges in chemistry is finding new pathways to utilize abundant small molecules such as N₂, CO₂, or O₂ for chemical transformations. The Haber-Bosch synthesis, a large-scale process to prepare ammonia from N₂ and H₂, has been optimized for decades. Yet, it requires enormous amounts of energy and considerable resources to prepare H₂ and activate the strong N≡N bond in dinitrogen, making it both economically and environmentally expensive. Developing alternative catalytic systems that operate under ambient conditions using earth-abundant elements is therefore an urgent research goal. In this project, we propose the design and development of a novel class of pnictogen-substituted N-heterocyclic ligands (NHC-G15, where C = As, Sb, or Bi). These ligands are Group 15 analogues of N-heterocyclic carbenes, in which the central carbene carbon is replaced with a heavier pnictogen atom (As, Sb, and Bi). While they are not true carbenes, they retain strong σ-donor properties and offer unique radical stabilization and redox-active behaviour, enabling the formation of low-valent metal complexes with potential for small molecule activation. The incorporation of a main group radical center introduces electronic flexibility and mimics redox-active cofactors found in enzymatic systems. We aim to synthesize and stabilize radical pnictogen species in situ using reducing agents such as KC₈, followed by their coordination to Group 6 transition metals (Cr, Mo, W). These main group–transition metal heterobimetallic complexes are inspired by the FeMo-cofactor of nitrogenase enzymes and are expected to exhibit cooperative reactivity toward N₂ binding and activation. Their modular ligand environment will allow tuning of electronic and steric factors to favour N₂ activation pathways, possibly leading to partial or complete reduction to ammonia or related intermediates. Investigating such complexes will also help clarify fundamental aspects of metal-ligand redox cooperativity and electron transfer during small-molecule activation. Additionally, we plan to develop a second generation of ligand frameworks that incorporate carboxylate functionalities for the construction of metal-organic frameworks (MOFs). These will enable translation of the molecular catalytic activity to solid-state systems with improved stability and recyclability. The project combines synthetic inorganic chemistry, spectroscopic and structural analysis, and computational modelling (DFT) to understand the structure-property relationships and catalytic mechanisms. Such research remains rare in India and represents a novel direction in main group-transition metal cooperativity for N₂ activation, offering a sustainable alternative to the Haber-Bosch process and contributing to the development of environmentally friendly nitrogen fixation technologies.