Research Projects

The development of chiral covalent organic framework (CCOF) catalysts is essential and highly valued in synthetic chemistry for synthesizing enantiopure organic compounds. While photocatalytic asymmetric reactions using CCOFs are eco-friendly and sustainable, they remain complex. Chiral covalent organic frameworks, known for their porous crystalline nature, have emerged as an excellent platform for exploring new chiral photocatalytic materials due to their precise tunability, inherent chiral structures, and functional versatility. Achieving high stereochemical control in photocatalytic asymmetric organic transformations poses significant challenges due to the high reactivity and instability of photoexcited organic molecules and intermediate radicals. To overcome these difficulties, Meggers' group developed an innovative approach involving the use of chiral-at-metal complexes as chiral photosensitizers for a range of enantioselective reactions in homogeneous conditions. These propeller-shaped metal complexes are enantiomerically pure, featuring mirror-image Δ- and Ʌ-enantiomers. It is well established that the closer the chiral centre is to the substrate bound to the catalyst, the greater the chiral induction and selectivity in the final product. Additionally, the formation of hydrogen bonds with the substrates enhances chiral induction in the product. In this project, we will synthesize and incorporate chiral-at-metal complexes of Ir or Rh (with Δ and Ʌ chirality) into COFs featuring suitable photoactive linkers with free NH groups for hydrogen bonding. The goal is to develop enantiopure chiral COFs as standalone heterogeneous photocatalysts. This recyclable heterogeneous catalyst will function as both a Lewis acid (through the metal centre to bind prochiral substrates) and a visible-light-induced photoredox catalyst for asymmetric organic reactions and drug development under greener conditions. We will carry out the complete synthesis and characterization of the new chiral COF as a standalone photocatalyst. The application of chiral COFs in photocatalytic enantioselective organic transformations under mild conditions will be explored, including their use in the synthesis of bioactive molecules such as (R)-(-)-Kjellmanianone, (S)-α-M4CPG, and (+)-Coixspirolactam A. The process will be scaled up for industrial and commercial purposes.