Chemistry

Head of Department

Dr. Atanu Singha Roy
Ph.D. from IIT Kharagpur

E-mail:
asroy86@nitm.ac.in

Area Of Research

Dr. PareshNath Chatterjee -Transition metal catalyzed organic transformations.

Dr. Gitish K. Dutta - Synthesis and application of organic materials.

Dr. Atanu Singha Roy:
Biophysical Chemistry

 

Protein-Ligand interaction at molecular level: Proteins have complex structures, consisting of different amino acids. They posses different functional roles based on the amino acid sequence. The protein molecules can form complex with other small drug like molecules via non-covalent interactions that may leads to change in structural and functional aspects of the proteins. The dietary polyphenols are the important class of components having lots of biological and physiological activities e.g. anti-oxidant, anti-inflammatory, anti-diabetic, anti-viral etc. Their interactions with different biological targets e.g. serum albumins, lysozyme and hemoglobin are significant on the background of drug transportation and delivery.

The binding of dietary polyphenols with the proteins are studied with the help of various biophysical techniques: absorption spectroscopy, fluorescence spectroscopy, circular dichroism (CD), Fourier transform infrared spectroscopy (FT-IR) and MALDI-ToF analyses. Molecular docking studies (using Autodock tools) are also conducted to find out the exact binding location of small molecules in the biomacromolecules. (Molecular BioSystems 12, 2016, 1687-1701; Journal of Inclusion Phenomena and Macrocyclic Chemistry 84, 2016, 21-34; Molecular BioSystems 12, 2016, 2818-2833)

Protein Denaturation/renaturation Studies: The unfolding and refolding phenomena of protein structures are also investigated using steady state fluorescence spectroscopy and lifetime measurements. (Molecular Biology Reports 40, 2013, 3239-3253; Journal of Luminescence 145, 2014, 741-751, 2014; Journal of Pharmaceutical Analysis 6, 2016, 256-267)

Glycation of proteins and binding with dietary polyphenols: The proteins are modified by reaction with different reducing sugars via non-enzymatic pathways in different stages of diabetes and glycemia. The glycated analogue is characterized by UV-vis, fluorescence, CD and MALDI-ToF techniques. Currently we are investigating the effects of glycation on the binding of dietary polyphenols with serum albumins. (Journal of Inclusion Phenomena and Macrocyclic Chemistry 85, 2016, 193-202; Journal of Biomolecular Structure & Dynamics 34, 2016, 1911-1918)

DNA-Ligand binding and DNA damaging experiments: The DNA binding and damaging studies of different metal complexes are underway. Various biophysical techniques will be used to analyze the same. (Molecular BioSystems 12, 2016, 1687-1701; Molecular BioSystems 12, 2016, 2818-2833).

 

Dr. Naba Kamal Nath:

(a) Novel Solid State Forms of Pharmaceuticals: Solid state forms of pharmaceuticals include polymorphs (same chemical species with different crystal structures), solvate/hydrate (molecular solid which includes solvent/water in its crystal lattice), salt (multi-component ionic solid), cocrystal (multi-component molecular solid), amorphous form, mixed crystal etc. We are interested in discovering and developing novel solid state forms of pharmaceutically active compounds as each of these solid state forms can modulate physico-chemical properties of drug substances and are therefore suitable candidates for new/alternate oral solid dosage forms.

(b) Stimuli Responsive Materials: Materials capable of responding under the influence of external stimuli (such as heat, light, pH gradient, moisture, mechanical force etc.) by changing its shape, size, colour, or by displaying various mechanical movements such as bending, curling, jumping (photosalient effect, thermosalient effect), twisting etc. have immense importance as material for energy conversion. We are interested in the synthesis, characterization, mechanistic studies and kinematic analysis of such stimuli responsive crystalline, liquid crystalline, polymeric and gel materials.

 

Dr. Mukul Pradhan

We are highly interested to work on nanostructured materials and their diverse applications where synthesis, characterization and analytical skills are applied synergistically. Core experiments include X-ray diffraction, Fourier transform infrared, photoluminescence, Raman, X-ray photoelectron spectroscopy, Atomic Force Microscope. Current application areas of interest include materials for energy, water purification, SERS and electrochemical based sensing of biomolecules and toxic metal ions. Cyclic voltammetry will also be used for energy (catalyst for generation of hydrogen from water) application.

(a) SERS based Sensing
Recent developments in biomedical science established Raman scattering as a promising tool for in vivo cancer detection within the near-infrared optical window (700–900 nm), where endogenous tissue absorption coefficients are more than two orders lower in magnitude compared to blue and ultra-violet light. Synthesis of NIR active SERS substrate/NIR Raman reporter is very important for biosensing. In our recent work, we observed the effect of composite Ag-FeOOH/Au@MnOOH/Ag@MnO2 (dendrite/nanoflower/nanowire) for the giant SERS enhancement with the probe molecule down to the single molecular level (EF >1011) due to the charge transfer as well as electromagnetic enhancement. The marked increase in the Raman activity of molecules adsorbed on substrates like Au-SiO2, Au-TiO2, Ag-CuO etc. Proteins have their distinct isoelectric pH. Above and below the isoelectric pH they become positive or negative. Then a particular protein can be attached onto the nanocomposites as a guest (depending on the charge of the noble metal in the nanocomposite) with the newly formed hybrid-nanocomposites that help sensing particular protein molecule using SERS. This idea can be applied even to charged toxic species. Literature study as well as our experimental observation confer that such composite nanomaterial would be promising SERS sensor. 
(b) Water splitting

Solar energy is green and renewable energy which will be the one of the best remedy for the future crisis of natural resources of energy in earth that could provide sufficient energy to power humanity’s needs. Hydrogen is considered as the energy carrier of the future as no green house gas like CO2 is emitted when hydrogen is burnt and it can be generated from source like water. However, its intermittent nature necessitates an efficient method of storage. Attention was focused on photocatalytic generation of hydrogen from water after the discovery of Fujishima and Honda. They have demonstrated that overall water splitting can be accomplished with the help of a photoelectrochemical cell made of a single crystalline TiO2 (rutile) anode and a Pt cathode under ultraviolet (UV) irradiation and operated with an external bias. Hydrogen fuel generation by photoelectrochemical (PEC) water splitting has been considered as one of the most promising methods to store solar energy. Hydrogen fuel generation by photoelectrochemical (PEC) water splitting has been considered as one of the most promising methods to store solar energy. To split water, a thermodynamic potential of 1.23 V is required. However, due to the overpotential losses associated with the reaction kinetics, usually 1.7 V or more is needed for practical rates to be achieved. A large band gap is a requirement in order to provide enough photovoltage while keeping the band gap small enough to absorb sufficient sunlight is a dilemma for a single absorber water-splitting device. To solve this problem, tandem configurations have been anticipated that use multiple absorbers that cover a larger portion of the solar spectrum and together generate enough photovoltage to drive the overall water splitting reaction.

 

Dr. Amit Kumar Paul

Nonadiabatic transition is one of the most fundamental processes that is present in processes like photosynthesis, vision, photochemistry, biomolecules stability, etc. On this research area, theoretical developments of beyond Born-Oppenheimer theories with appropriate application to spectroscopic problems through quantum and semiclassical dynamics have been very popular among theoretical chemistry community. Understanding the nature of non-adiabatic coupling terms (NACTs) is very important in this research. Ab initio quantum chemistry packages can be used to calculate NACTs and potential energy surfaces (PESs) of a molecular system as functions of normal or local modes. The calculated quantities can be used to perform adiabatic to diabatic transformation (ADT) of Schrödinger equation, and construct uniquely defined diabatic PESs in the configuration space. In a semiclassical process, the “surface hopping” model can be applied with an “on-the-fly” dynamics in the regions where potential energy curves are strongly coupled. In a classical dynamics simulation, a bath model has been developed recently to study collisional energy transfer phenomena. In this model, a 3D box, implemented with periodic boundary condition, can be taken with thousand or more solvent molecules. Any solvent bath density from liquid to gas may be considered. A highly vibrationally excited solute molecule is placed at the middle of the box and the equilibrated solvent molecules are allowed to collide with this hot solute. Relaxation of energy of the hot solute molecule is measured versus time and energy transferred per collision is obtained which can directly be compared with the experiment. The model can be applied to study any reaction dynamics in the presence of solvent molecules with appropriate force-field. Study of QM/MM dynamics can be also done with such a model.