HomePublications Publications Sugunan, A., Ahirwar, M. B., Suresh, C. H., Deshmukh, M. M., & Rajendar, G. (2024). Cooperative noncovalent interactions controlling amine-catalyzed aldol reaction pathways catalyzed by bifunctional amino quaternary phosphonium ion. Journal of Organic Chemistry, 89(16), Article 4c01635. https://doi.org/10.1021/acs.joc.4c01635 Abstract: Members of a new class of bifunctional amino quaternary phosphonium salts have been synthesized and utilized as catalysts in aldol condensation reactions, as demonstrated herein. These secondary amines feature a phosphonium ion connected by a carbon chain, enabling the quaternary phosphonium ion to engage in distinct cooperative noncovalent interactions. These interactions work in tandem to stabilize different transition state complexes, exclusively controlling competing amine-catalyzed aldol pathways via the Mannich mechanism. Comprehensive mechanistic investigations were conducted through theoretical calculations. This study uncovers a proximity-driven catalytic mechanism in which the distance between the N and the P+ of the bifunctional catalyst emerges as a critical factor determining catalytic efficacy. The method has been demonstrated through its application to the total synthesis of several bioactive natural products. Dupud, R., Thushara, R., Merugu, K. K., Suresh, C. H., & Ramesh, R. (2024). Radical Cascade Annulation of Biphenyl Acrylamides to Dibenzoazepinones: Experimental and DFT Studies. European Journal of Organic Chemistry. https://doi.org/10.1002/ejoc.202400450. Abstract:An efficient method for the conversion of biphenyl acrylamides to dibenzoazepinones with -SCF3 incorporation is described. This operationally simple radical cascade reaction employs CAN as an oxidant and exhibits good functional group tolerance. Substrates featuring -OCH3, -CH3, -Br or -Cl at the para-position of the aromatic ring exhibits a preference for an ipso-cyclization due to the intervention of DMSO in the reaction. Density functional theory (DFT) calculations provide valuable insights into the reaction’s energetics and product selectivity. Norbert, A., Surya Mary, A., John, S. S., Shaji, S., Jacob, M. V., & Philip, R. R. (2024). Green synthesized Cu-doped CeO2 nanoparticles for Congo red dye adsorption and antibacterial action. Nanotechnology, 35(26), 265708. https://doi.org/10.1088/1361-6528/ad3649. Abstract: The removal of pollutants from water bodies is crucial for the well-being of humanity and is a topic of global research. Researchers have turned their attention to green synthesized nanoparticles for wastewater treatment due to their eco-friendly nature, biocompatibility, and cost-effectiveness. This work demonstrates the efficient removal of organic dye and both gram-positive and gram-negative bacteria from water bodies using copper-doped cerium oxide nanoparticles synthesized with Murraya Koenigii extract. Characterized via various methods, the 15% copper doped cerium oxide nanoparticles (Cu 15% NPs) exhibited maximum Congo red dye adsorption (98% degradation in 35 min). Kinetic analysis favoured a pseudo-second-order model, indicating the chemical nature of adsorption. Equilibrium adsorption isotherms aligned with the Langmuir model, indicating homogenous monolayer dye adsorption on the doped adsorbent. The maximum uptake of adsorbate, Qm obtained from Langmuir model for Cu 15% NPs was 193 mg g−1. The study also showed enhanced antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa for Cu-doped ceria, attributed to generation of reactive oxygen species (ROS) induced by the redox cycling between Ce3+ and Ce4+. This substantiated that the green synthesized copper doped cerium oxide nanoparticles are potential candidates for adsorptive removal of Congo red dye and as antibacterial agents.
