Research Projects

Chirality is a fundamental feature of nature, observed from simple molecules like amino acids to complex macromolecules such as proteins and DNA, which perform essential biological functions. Inspired by this natural precision, researchers have developed artificial helical systems using π-conjugated organic chromophores. Among these, supramolecular systems formed via reversible non-covalent interactions have emerged as dynamic, stimuli-responsive platforms for controlled chirality generation and amplification. An intriguing feature of chiral assemblies is their ability to control electron spin via the Chiral-Induced Spin Selectivity (CISS) effect, where chiral molecules preferentially transmit electrons of a specific spin without a magnetic field. This has promising applications in spintronics and quantum information. However, most studies focus on rigid, covalent systems like DNA, peptides, and helicenes, which offer limited tunability. In contrast, flexible supramolecular systems remain underexplored despite offering enhanced adaptability and external control. To bridge this gap, we aim to design and synthesize two classes of π-conjugated chiral systems: perylene diimide (PDI) and porphyrin-based derivatives. PDI allows bay-position functionalization, enabling precise control over its electronic and self-assembly behaviour. A series of bay-substituted PDIs bearing electron-donating (–CH₃, –OCH₃, –NH₂) and electron withdrawing groups (–F, –CN, –NO₂) will be synthesized to modulate electron density and aggregation properties. EDG-substituted PDIs are expected to form flexible, twisted aggregates, while EWG-functionalized derivatives should promote planar, rigid stacking. In parallel, we will synthesize chiral porphyrin molecules by strategically functionalized with different amino acid derivatives having the variation in α-position of these amino acids. This variation at α-position of these amino acids provides control over steric bulk and flexibility, which will be used to modulate supramolecular helicity and spin-selective behaviour. This electronic tuning approach through bay-substitution in PDI and α-substituent variation in porphyrin derivatives will enable precise control over photophysical, chiroptical, and spin-selective properties. The resulting supramolecular aggregates, ranging from flexible helices to rigid planar stacks, will generate distinct chiral environments and energy landscapes critical for efficient spin filtering. Twisted architectures with extended π-conjugation are expected to enhance spin–orbit coupling and coherent charge transport, both essential for the manifestation of the CISS effect. This study not only advances the understanding of structure-property relationships in dynamic chiral assemblies but also helps for designing next-generation functional materials with promising applications in chiral sensing, chiral optoelectronics and spintronic devices.