http://dspace.dtu.ac.in:8080/jspui/handle/123456789/3 2026-10-17T21:42:54Z 2026-10-17T21:42:54Z ARORA, PRIYANKA Singh, Ram (SUPERVISOR) http://dspace.dtu.ac.in:8080/jspui/handle/repository/23404 2026-10-16T06:36:51Z 2026-07-01T00:00:00Z

Title: DESIGN, SYNTHESIS, AND APPLICATIONS OF INDOLE AND ISOINDOLE DERIVATIVES Authors: ARORA, PRIYANKA; Singh, Ram (SUPERVISOR) Abstract: The present work entitled “Design, Synthesis, and Applications of Indole and Isoindole Derivatives” has been divided into six chapters. Chapter 1 covers the general description of various synthetic methodologies of indole and isoindolin-1-one heterocyclic compounds and their biological applications. Chapter 2 covers the in-silico studies of 3-acyl-3-hydroxyisoindolin-1-one derivatives as potential MAO-B inhibitors for neurodegenerative diseases focusing on PD. A large library of 279 derivatives was created and molecular docking of the complete library was performed. Then, the top two docked scored compounds were further investigated using other parameters such as MDS, MM-GBSA binding free energy, ADME, and DFT studies. Two ligands, 3 hydroxy-2-(4-isopropylphenyl)-3-(4-(trifluoromethyl)benzoyl)isoindolin-1-one (90) and 2 (3,4-dichlorophenyl)-3-hydroxy-3-(4-(trifluoromethyl)benzoyl)isoindolin-1-one (173) displayed superior docking score values of -12.088 kcal/mol and -12.085 kcal/mol, respectively. MDS over 500 ns demonstrated the stability of both the ligands 90 and 173 with RMSD and RMSF values below 2 Å. ADME profiling of both ligands indicated favourable pharmacokinetic parameters, while DFT analysis showed high chemical reactivity and low kinetic stability. This suggested that ligands 90 and 173 exhibit strong potential as promising lead candidates for MAO-B inhibition. Chapter 3 discusses a new Selectfluor-mediated synthetic route for the regioselective synthesis of 3-acyl-3-hydroxyisoindolin-1-ones from N-substituted-2‑(1-alkynyl)benzamides with sodium bicarbonate as mild base in acetonitrile solvent. Water was used as the source for oxidation and hydroxylation. All the derivatives of 3-acyl-3-hydroxyisoindolin-1-ones were synthesized and characterized with 73-85% isolated yield. Control experiments revealed that this new synthetic method followed free radical pathway. Anti-oxidant activities of synthesized compounds are also discussed in this chapter. Chapter 4 covers the in-silico studies of N-alkenylindole derivatives to evaluate their inhibitory activity against MAO-B. A library of 147 N-alkenylindole ligands was made and molecular docking of the complete library with the MAO-B protein target was performed. Further, the top two docked scored ligands were investigated using other in-silico tools which were MDS, MM-GBSA binding free energy, ADME, and DFT studies. Two ligands, 3-(1 (1,2,3,6-tetrahydro-[1,1'-biphenyl]-4-yl)-1H-indol-2-yl)phenol (66) and 2-(4-fluorophenyl)-1 (1,2,3,6-tetrahydro-[1,1'-biphenyl]-4-yl)-1H-indole (63) showed superior docking scores of 11.8 kcal/mol and -11.4 kcal/mol, respectively in their library. MDS performed over 500 ns 9 demonstrated lower RMSD and RMSF values for ligand 66 compared to ligand 63, indicating greater ligand 66-protein docked complex stability. Post-MDS MM-GBSA calculations depicting energetically favourable interactions. ADME profiling of both ligands indicated favourable drug-likeness and physicochemical properties. Whereas DFT analysis showed higher chemical reactivity and low kinetic stability of ligand 66 compared to ligand 63. Chapter 5 covers a new metal-free synthetic method for the regioselective synthesis of N alkenylindoles from 2-(1-alkynyl)anilines and cyclic ketones catalyzed by molecular iodine in toluene:DMF (20:1, v/v) solvent ratio. This developed method facilitated the synthesis of 19 derivatives with yields ranging from 56 to 73 % yield, of which 18 are new derivatives. This developed method was well tolerated the presence of both electron-donating and electron-withdrawing groups including hetero-aromatic rings. According to control experiment, this new synthetic route follows an ionic pathway. Moreover, the antioxidant activities of the synthesized N-alkenylindole compounds were evaluated and discussion in this chapter. Chapter 6 is the conclusion chapter where all the work carried out has been summarized, followed by future prospects and social impact.

2026-07-01T00:00:00Z KUMARI, PRATIBHA Kumar, D. (SUPERVISOR) http://dspace.dtu.ac.in:8080/jspui/handle/repository/23395 2026-10-16T06:35:40Z 2026-07-01T00:00:00Z

Title: FABRICATION OF NOVEL ELECTROCHEMICAL BIOSENSOR FOR FENITROTHION DETECTION USING G-C3N4@ZNO-NIO NANOHYBRID Authors: KUMARI, PRATIBHA; Kumar, D. (SUPERVISOR) Abstract: A widespread utilization of organophosphate pesticides in the agriculture sector has led to serious environmental and public health issues due to the toxicity and non-biodegradability. One of the most commonly used organophosphate pesticides, fenitrothion, can enter water, soil and food products causing serious health effects to people and ecosystems. So, it is highly needful to evolve a rapid, sensitive and cost-effective detection method for fenitrothion monitoring. In the present study, a nanocomposite of graphitic carbon nitride (g-C3N4) and zinc–nickel oxide (ZnO NiO) has been successfully fabricated to develop an electrochemical biosensor for sensitive detection of fenitrothion. Graphitic carbon nitride was synthesized by thermal polymerization of melamine and the zinc–nickel oxide nanostructures were synthesized by a hydrothermal synthesis method. The synthesized nanomaterials were further used to make a hybrid nanocomposite that exhibited improved conductivity, high surface area and better electrocatalytic activity. The fabricated nanocomposite was then coated on an indium tin oxide (ITO) electrode to fabricate an electrochemical biosensor. X-ray diffraction, field-emission scanning electron microscopy and Fourier transform infrared spectroscopy were used to characterize the synthesized materials structurally and morphologically. Cyclic voltammetry and differential pulse voltammetry were also used for the electrochemical studies. The developed biosensor was highly sensitive, rapid, highly selective and had a low detection limit for fenitrothion. The synergistic effect between g-C3N4 and Zn-Ni oxide was believed to be responsible for the improved sensing performance by providing efficient electron transfer and making a more active sensing.

2026-07-01T00:00:00Z VARSHNEY, GUNJAN Kaur, Raminder (SUPERVISOR) Zulfequar, Mohammad (CO-SUPERVISOR) http://dspace.dtu.ac.in:8080/jspui/handle/repository/23378 2026-10-16T06:33:31Z 2026-09-01T00:00:00Z

Title: FABRICATION AND EVALUATION OF ENCAPSULATED PHASE CHANGE MATERIALS FOR LATENT HEAT STORAGE Authors: VARSHNEY, GUNJAN; Kaur, Raminder (SUPERVISOR); Zulfequar, Mohammad (CO-SUPERVISOR) Abstract: The growing global energy demand and overreliance on fossil fuels like coal and petroleum have resulted in serious environmental issues such as climate change, greenhouse gas emissions, and ecological imbalance. The pursuit of sustainable energy management technologies that can boost energy efficiency while lessening the demand on non-renewable resources has accelerated due to these concerns. Among numerous approaches, thermal energy storage (TES) systems have emerged as a viable alternative for storing excess thermal energy and releasing it whenever it is required. Phase change materials (PCMs) have drawn a lot of attention in this regard because of their capacity to store and release a significant quantity of latent heat during phase transition at constant temperatures. Among the several PCMs, Eicosane (ESE) is well known for its high latent heat storage capacity, non-corrosive nature, chemical stability, and appropriate melting temperature for applications involving low-temperature TES. The core PCM in this work is ESE, which has a melting point of about 38.9 °C and a melting enthalpy of 239.9 J.g-1. Despite its benefits, paraffin-based PCMs have numerous intrinsic drawbacks that limit their practical application, including limited thermal conductivity, poor structural stability, and leakage during the phase change process. As a result, the current thesis is focused on producing advanced material techniques to overcome these obstacles and broaden the application of paraffin-based PCMs. To achieve the desired objectives, ESE was first microencapsulated into polymeric shell of polystyrene (PS) by a mini-emulsion polymerization process aided by probe sonication, where polybutylacrylate (PBA) copolymer shell was also used to increase structural integrity. The resultant microencapsulated phase change materials (MPCMs) showed an encapsulation ratio of 91.9%, encapsulation efficiency of 91.6%, with a melting enthalpy of 220.5 J.g-1. The thermal stability and behaviour of the microcapsules were systematically analyzed using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) while diffusion tests were carried out to assess leakage resistance. The findings demonstrated that, in comparison to pure ESE, the microencapsulated systems had noticeably improved thermal stability. Additionally, paraffin was encapsulated at the nanoscale to produce nanoencapsulated phase change materials (NPCMs), which further enhanced heat transfer properties and interfacial xxv interactions. The PCM's thermal responsiveness is improved by the increased surface area that the smaller particle size offered, which promotes interaction between the PCM and its surroundings. The synthesized NPCMs possessed an encapsulation ratio of 93.6%, encapsulation efficiency of 87.2%, and melting enthalpy of 224.6 J.g-1. The efficient encapsulation of ESE within the polymeric shell of polystearylmethacrylate was verified using Fourier Transform Infrared Spectroscopy (FTIR), while the particle size distribution of the produced nanocapsules was ascertained. Further research includes the development of microcapsules with varying crosslinking agent ratios within the polymer shell in order to optimize the thermal stability of the MPCM and investigate their effects on structural strength. The thermal performance and stability of these MPCMs were assessed using DSC and TGA techniques, and significant thermal parameters were calculated from the thermograms in order to assess their performance as TES systems. Among the investigated formulations, EPD5 exhibited a melting enthalpy of 170.5 J.g-1, an encapsulation ratio of 62.4%, and an encapsulation efficiency of 68.3%. The encapsulated PCM system was supplemented with synthesized thermal conductive nanoparticles (NPs) to improve the overall thermal performance of the tailored microcapsules. Powder X-ray Diffraction (PXRD) analysis revealed the amorphous nature of the surrounding polymer shell and validated the structural properties of these NPs. The inclusion of NPs improved the thermal response of the encapsulated PCM system. The ZnATH-(O) NP-doped MPCM (Z7) showed a melting enthalpy of 186.8 J.g-1, while the FeATH-(O) NP-doped MPCM (F5) exhibited a melting enthalpy of 226.2 J.g-1, with encapsulation ratios of 77.9% and 94.3%, respectively. In addition to encapsulation techniques, shape-stabilized phase change materials (SSPCMs) were produced using porous supporting material to mitigate seepage during the phase transition of the PCMs. The optimized ESE/MWCNT SSPCM (SS-EM@9) achieved a melting enthalpy of 215.3 J.g-1 and crystallization enthalpy of 212.7 J.g-1, with a thermal storage capacity of 99.8%. The morphological features of the composites were evaluated using Field-Emission Scanning Electron Microscopy (FE-SEM), which revealed the efficient inclusion of PCM inside the porous structure. The obtained SSPCMs showed enhanced thermal stability and remarkable structural integrity. xxvi Overall, this study provides a thorough investigation into the design, synthesis, and characterization of MPCMs, NPCMs and SSPCMs for efficient TES. The synthesized novel materials exhibit improved stability and performance, indicating their potential for real-world applications in TES technologies. This research makes a substantial contribution to the fields of materials engineering, polymer science, and energy storage. It also offers a viable solution to lessen reliance on non-renewable energy sources while promoting sustainable energy management.

2026-09-01T00:00:00Z JAIN, ANUBHAV Purwar, Roli (SUPERVISOR) http://dspace.dtu.ac.in:8080/jspui/handle/repository/23335 2026-10-16T06:26:24Z 2026-05-01T00:00:00Z

Title: TO STUDY THE EFFECTS OF SURFACTANTS ON THE PROPERTIES OF POLY (METHYL METHACRYLATE CO-ACRYLIC ACID) PREPARED BY BATCH EMULSION POLYMERIZATION Authors: JAIN, ANUBHAV; Purwar, Roli (SUPERVISOR) Abstract: The growing demand for environmentally friendly and high-performance waterborne coatings has significantly increased the importance of emulsion polymerization in the coatings industry. Acrylic emulsions prepared through emulsion polymerization are extensively used due to their excellent film forming ability, durability, chemical resistance, and low volatile organic compound (VOC) emission. Among the various factors influencing the properties of acrylic emulsions, surfactants play a crucial role in determining particle formation, colloidal stability, rheological behavior, and final coating performance. In the present study, the effects of different surfactant systems on the properties of poly (methyl methacrylate-co-acrylic acid) [PMMA-co-PAA] prepared by batch emulsion polymerization were investigated. The emulsion polymerization was carried out using methyl methacrylate (MMA) and acrylic acid (AA) as monomers in an aqueous medium through free radical batch emulsion polymerization. Sodium dodecyl sulfate (SDS), cocamidopropyl betaine (CAPB), and amphoteric fluorosurfactant (AMF-1) were employed as surfactants to study their influence on emulsion characteristics and coating properties. APS was used as an initiator for the polymerization process. Several formulations of latex were prepared with different concentrations of surfactants while keeping the other variables constant. The latexes obtained through this process were characterized on the basis of monomer conversion, solid content, particle size, zeta potential, rheological behavior, and wettability properties. From the gravimetric determination, it was found that the prepared emulsions had high conversion rate of the monomers along with good solid content values. This suggested the efficient polymerization of the monomers in addition to adequate stabilization of the latex particles. The use of various types of surfactants played a significant role in the efficiency of the polymerization process as well as stability of emulsions. DLS studies indicated that surfactant type plays a very important role in determining particle size and colloidal stability of the prepared emulsions. It was found that the fluorsurfactant systems gave rise to relatively smaller particles size with narrower distribution than others. Rheology studies conducted such as viscosity testing, amplitude sweep, and frequency sweep tests have provided useful information regarding the viscoelastic nature of the emulsions. All tested latex systems showed a non-Newtonian shear-thinning behavior, which is favorable when it comes to use in coating applications. It was found that rheological properties of emulsions depended strongly on the type of surfactants used and the interactions between the particles within the emulsion system. Amplitude sweep testing showed the presence of the linear viscoelastic region in all samples studied and differences in structural stability of tested latex samples. Differences in elastic and viscous VI behavior of the emulsions depending on the used surfactants could be observed from frequency sweeps data. Wettability behavior of coating films obtained from various surfactant systems was determined by measuring the water contact angles. Latex systems with fluorosurfactants were found to show much higher water contact angles than traditional surfactant systems, demonstrating the increased hydrophobicity and reduced surface energy of such emulsion systems. Increased water repellent property of fluorosurfactants can be explained by the presence of fluorinated portions in the molecular structure of fluorosurfactants, reducing the surface tension and making coating films more hydrophobic. In summary, the current study revealed that surfactant choice is an essential factor for influencing the physicochemical, rheological, and surface characteristics of PMMA-co-PAA emulsions using batch emulsion polymerization techniques. Of all the tested surfactants, amphoteric fluorosurfactants have exhibited excellent performance in respect to particle size, emulsion stabilization, rheology, and enhanced hydrophobicity. The results from this study will offer useful information in formulating advanced acrylic emulsions for eco-friendly coating purposes.

2026-05-01T00:00:00Z