Research Projects

Polycyclic aromatic hydrocarbons (PAHs) with helical topologies have been a subject of interest in chemistry, materials science, and biology. Heterohelicenes, a subclass of PAHs, offer fine-tuning of electronic, optical, physical, and semi-supramolecular properties based on the number, position, and nature of fused heterocycles. Expanded heterohelicenes, an emerging class of flexible helicenes, have gained recent research focus due to their unique structural and electronic features. However, limited synthetic strategies to access these molecules hinder their rapid development. This project proposes a modular organometallic-based catalytic protocol for synthesizing expanded heterohelicenes with stimuli-responsive core and peripheral modules. The rhodium(III)-catalyzed method, called "rollover π-expansion (ROPE)," involves concurrent linear and angular ring fusions on imidazolium/imidazole-containing pyridines as templates. The redox-responsive expanded heterohelicenes will be explored to develop new redox-based catalysts for electrocatalytic hydride transfer reactions, such as electrocatalytic CO2 reduction reaction (eCO2RR) and hydrogen evolution reaction (HER). Light-responsive and pH-responsive flexible heterohelicenes will be investigated to unravel light-controlled reversible photomechanical and pH-controlled chemomechanical properties, which are the basis for designing soft molecular springs for various task-specific actuation and sensing applications.