Talk Session 1

Transition Metal Complexes in the Dual Worlds of Biomimetic Enzyme Modelling and Biomedical Application Studies

The utility of transition metal complexes in modelling metalloenzymes bearing synthetically challenging mono and multi-nuclear active sites would be explored in the talk, particularly from the perspective of their development as the synthetic mimics of a variety of enzymes starting with a dioxygenase enzyme namely, catechol dioxygenase, to two oxidase enzymes, namely, galactose oxidase and catelchol oxidase. These model complexes were studied with the intent of tracing out the pathways of the molecular oxygen interaction with transition metal occurring in the biological systems. Proceeding further, the structural and functional models of a more intriguing hetero-dinuclear active site of another much-renowned phophoester bond cleaving enzyme namely, Purple Acid Phosphatase (PAP) were studied. Lastly, proceeding beyond the small molecule biomimetic enzyme modelling studies, the development of transition metal organometallics as metallopharmaceuticals for potential chemotherapeutic applications would also be highlighted in the talk.

Investigation on the Cooperative Binding Mechanism for the Adsorption of CO in Fe-Triazolate MOF

MOFs have been attracted wide interest in past few decades due to their potential applications in various field such as gas storage and adsorption. Recently, these frameworks have received extended applications in fields such as molecular sensing, catalysis, conductivity and drug delivery. Though several modifications have been done to improve the efficiency of MOF, less studies are done to improve the magnetic properties of them. So, our focus is to target the tuning of the magnetic properties of the metal centre of the framework. Paramagnetic centres offer additional flexibility to the ground state via this magnetic switchable nature and stabilizing radical interactions, thereby highly influencing the gas binding properties of MOFs. So, I would like to extent my interest to the improvement of paramagnetic MOFs which possess fascinating properties such as cooperative binding, magnetic switching, flexible ground state etc. Cooperative binding is a phenomenon in which the binding of guest molecule at one site triggers the binding at neighbouring sites and thereby an improved uptake of the adsorbent gases. In our study, we have theoretically investigated the spin transition mechanism for cooperative adsorption which happens in Fe-bistriazole based MOF reported by R. Long et.alThe studies have shown that the Fe-triazolate hexagonal MOF is unique system for the selective binding of CO via cooperative spin transition mechanism, which means the binding at one Fe site essentially triggers the binding at nearby sites by reducing the energy barrier for binding via cooperativity. Cooperative mechanism influences the electronic environment of the framework and makes it flexible for further uptake of gases. We have proved the cooperative binging in this MOF by a detailed analysis of deformation energy of the system as well as exchange coupling interaction studies and spin density analysis.

Intermolecular coulombic decay in molecular clusters

Photoexcitation of van der Waals complexes can lead to several decay pathways depending on the complex nature of the potential energy surfaces involved. Upon excitation of the chromophore, energy transfer to and ionization of its weakly bound neighbor brings to light a unique relaxation process known as intermolecular Coulombic decay (ICD); a phenomenon of renewed focus owing to its relevance in biological systems. Here we report the ICD process in binary complexes of 2,6-difluorophenylacetylene with simple aliphatic amines such as dimethylamine and trimethylaminewhen subjected to resonant two-photon excitation localized on 2,6-difluorophenylacetylene. Velocity Map Imaging (VMI) is a technique to image the 3D velocity distribution of fragments produced after a reaction, especially photochemical reactions. The 3D velocity distribution is imaged on a 2D detector, which can be restored by suitable inversion methods such Abel Inversion. In this technique the excess kinetic energy of fragments produced in a reaction can be measured, which then can be used to understand the dynamics of the reaction path including the internal energy distributions.The kinetic energy distribution of the amine cations, measured using direct current slicing VMI technique. The experimental results combined with theoretical methods, provide valuable insights on the nature of ICD in van der Waals complexes and more importantly, the role of ICD following resonant photoexcitation using near UV radiation.

“Diketopiperazine(DKP) as Template for Functionalized porous polymer membrane”

Functionalized porous polymer materials are very important in the field of separation technology, biomedical technology, catalysis, water purification, ion transport, drug-delivery and ion-encapsulation. The use of peptide templates for synthesizing functionalized porous polymer membrane has remained less explored. We propose to use serine-derived diketopiperazines (DKPs), which are known to form nanotubes or spheres as templates. The templates are attached to norbornene monomer units using a cleavable ester linkage. These monomer attached templates upon polymerization and subsequent removal of template by hydrolysis will give porous polymer membranes functionalized with carboxylate groups.