BITS Faculty Publications
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Item Biochar-supported nanomaterials for environmental applications(Elsevier, 2019-10) Goonetilleke, AshanthaImmobilizing nanomaterials in highly porous, surface active, structurally stable biochar creates novel nanocomposites that combines the well-known advantages of both materials. The exceptional contaminant adsorption and/or catalytic degradation capabilities of these nanocomposites have attracted the attention of the scientific community for possible use in environmental applications. This paper reviews the different methodologies for synthesizing biochar-supported nanomaterials, the key physical and chemical characteristics of these nanomaterials, and their performance in environmental applications, as well as identifies current knowledge gaps and potential directions for further research and development.Item Engineered hydrochar production methodologies, key factors influencing agriculture wastewater treatment, and life cycle analysis: A critical review(Elsevier, 2023-12) Goonetilleke, AshanthaFor intensive food production, a range of chemical compounds are used to increase production, reduce the amount of weeds, and prevent pest infestation. Therefore, agricultural wastewater discharge to water bodies creates human health and environmental risks. This highlights the need for technologies to remove organic and inorganic pollutants, where adsorption using carbon-based materials has emerged as a cost-effective and promising alternative for agricultural wastewater treatment with high removal efficacy and alignment with the circular economy concept by generating value-added products, achieving energy conservation and reducing the environmental footprint. Among the different adsorbent materials, hydrochar (HC) has attracted attention because, compared to the thermal processes used for synthesizing other carbon-based materials, it requires relatively milder production conditions and possesses higher adsorption capability for water pollutants. Although HC holds advantages for the adsorption of water pollutants, HC modification using different methods has been found to improve the properties, including adsorption capacity. Accordingly, engineered hydrochar (EHC) has attracted research attention. However, past research publications show that the investigations have focused on material characterization and removal rates, with little knowledge created of the environmental impacts of HC production, application, and disposal. This study reviews current knowledge on EHC synthesis, characteristics, water treatment applications, and life cycle analysis. Initially, production methodologies were investigated to understand their influence on key surface physical and chemical characteristics. This was followed by assessing EHC efficacy for water and wastewater treatment. Finally, the environmental footprint of EHC production, application, and disposal was evaluated to identify critical knowledge gaps and to provide recommendations for future research.Item Steroid-triazole conjugates: A brief overview of synthesis and their application as anticancer agents(Elsevier, 2023-09) Sakhuja, RajeevSteroids are biomolecules that play pivotal roles in various physiological and drug discovery processes. Abundant research has been fuelled towards steroid-heterocycles conjugates over the last few decades as potential therapeutic agents against various diseases especially as anticancer agents. In this context various steroid-triazole conjugates have been synthesized and studied for their anticancer potential against various cancer cell lines. A thorough search of the literatures revealed that a concise review pertaining the present topic is not compiled. Therefore, in thus review we summarize the synthesis, anticancer activity against various cancer cell lines and structure activity relationship (SAR) of various steroid-triazole conjugates. This review can lay down the path towards the development of various steroid-heterocycles conjugates with lesser side effects and profound efficacy.Item Synthesis and characterization of Co3O4 spinel nanowall: understanding the growth mechanism and properties(IOP, 2024) Gangopadhyay, SubhashisFormation of spinel tricobalt tetraoxide (Co3O4) nanostructures through a controlled thermal oxidation process is discussed here. Thin films of high purity cobalt (Co) were deposited on glass/quartz substrates using an electron beam (E-beam) evaporation technique. Thermal oxidation of the as-deposited Co thin films was carried out at various oxidation temperatures (400 °C to 600 °C) for different durations (5 h to 15 h) to grow various oxide nanostructures. Different surface characterizations techniques were used to investigate the structure, chemistry and electronic properties of the as-grown cobalt oxide nanostructures. x-ray diffraction analysis revealed the presence of the CoO phase along with the Co3O4 phases at relatively lower oxidation temperature. However, the Co3O4 phase becomes more predominant for longer oxidation durations at higher oxidation temperatures. Field emission scanning electron microscopy analysis showed a surface morphological transition from nanowalls to nanograins with an increase in the oxidation temperature. The surface electrical conductivity of the oxidized Co films is also increased for higher oxidation temperature and/or duration mainly due to the oxide phase purity and larger particle sizes. Ultraviolet–visible spectroscopy indicated two distinct optical energy bandgaps, which effectively decreased with an increase in the oxidation temperature and duration. Raman spectroscopy identified five different Raman-active modes corresponding to the Co3O4 phase, with the F2g mode dominating at higher temperatures. All these findings provide clear insights into the structural, electrical, chemical and optical properties of cobalt oxide thin films. Moreover, it provides a mechanism on how to grow 2D nanowalls morphology of Co3O4 films which can further be used in energy, sensor or catalytic applications.Item Design, synthesis, and biological evaluation of novel quinoxaline aryl ethers as anticancer agents(Wiley, 2024-03) Murugesan, SankaranarayananWe designed and synthesized thirty novel quinoxaline aryl ethers as anticancer agents, and the structures of final compounds were confirmed with various analytical techniques like Mass, 1H NMR, 13C NMR, FTIR, and elemental analyses. The compounds were tested against three cancer cell lines: colon cancer (HCT-116), breast cancer (MDA-MB-231), prostate cancer (DU-145), and one normal cell line: human embryonic kidney cell line (HEK-293). The obtained results indicate that two compounds, FQ and MQ, with IC50 values < 16 μM, were the most active compounds. Molecular docking studies revealed the binding of FQ and MQ molecules in the active site of the c-Met kinase (PDB ID: 3F66, 1.40 Å). Furthermore, QikProp ADME prediction and the MDS analysis preserved those critical docking data of both compounds, FQ and MQ. Western blotting was used to confirm the impact of the compounds FQ and MQ on the inhibition of the c-Met kinase receptor. The apoptosis assays were performed to investigate the mechanism of cell death for the most active compounds, FQ and MQ. The Annexin V/7-AAD assay indicated apoptosis in MDA-MB-231 cells treated with FQ and MQ, with FQ (21.4%) showing a higher efficacy in killing MDA-MB-231 cells than MQ (14.25%). The Caspase 3/7 7-AAD assay further supported these findings, revealing higher percentages of apoptotic cells for FQ-treated MDA-MB-231 cells (41.8%). The results obtained from the apoptosis assay conclude that FQ exhibits better anticancer activity against MDA-MB-231 cells than MQ.Item Coumarin analogues as promising anti-obesity agents: in silico design, synthesis, and in vitro pancreatic lipase inhibitory activity(Wiley, 2025-01) Paul, Atish TulshiramA set of coumarin-3-carboxamide analogues were designed, synthesized, and evaluated for their ability to impede pancreatic lipase (PL) activity. Out of all the analogues, 5dh and 5de demonstrated promising inhibitory activity against PL, as indicated by their respective IC50 values of 9.20 and 11.4 μM, as compared to Orlistat (IC50 = 0.97 μM). It was found that analogue 5dh inhibited PL in a competitive manner with an inhibition constant (Ki) of 4.504 μM. Additionally, the docking analysis validated the interactions between the analogue 5dh (MolDock score of −140.251 kcal/mol) and key amino acids in the active site, including Leu 153, Gly 76, Arg 256, His 151, Phe 77, and His 263. The inhibitory activity of these analogues was significantly correlated with their MolDock scores (Pearson's r = 0.6586). Finally, molecular dynamics simulation was also performed for 100 ns in order to elucidate the stability, confirmation and intermolecular interactions of the active analogue 5dh. The results of this investigation suggested that the complex maintained its stability despite the dynamic conditions exhibiting interactions with important amino acids. In summary, the outcomes indicated that the synthesized analogues exhibited the potential to inhibit PL activity.Item A multifaceted scaffold for building bioactive compounds: phenothiazine(Bentham Science, 2023-07) Jain, AnkitIn the growing field of heterocyclic compounds, phenothiazine and the associated nucleus are among the most significant potential scaffolds with excellent pharmacological activities. The knowledge of chemistry, synthetic routes, and various physicochemical parameters of these compounds draws particular attention to create a chemical library. Related compounds synthesized by various routes have diverse pharmacological functions. The exhaustive search of phenothiazine literature helps the medicinal chemists who develop the molecules for designing new drugs. A broad view of the synthetic routes has been outlined in this study. This paper includes the chemistry, physiochemical properties, and various biological activities of phenothiazine and related compounds.Item Facile synthesis of ZnO/ZnS hollow nanorods via Kirkendall effect with enhanced photocatalytic degradation of methylene blue(Springer, 2023-03) Pande, SurojitBecause of the growing concerns about environmental issues, the search of proficient semiconductor catalysts for pollutants degradation from contaminated water is one of the interesting areas of research. Due to the larger surface area, hollow nanomaterials with hollow interior and outer thickness illustrate a class of significant nanostructured materials. The enhanced surface area provides remarkable applications of the hollow nanomaterials in catalysis. In Kirkendall effect, pores are formed owing to the diverse diffusion rates of two nanomaterials in a diffusion couple. Here, we have introduced the facile hydrothermal synthesis of hollow nanorods of ZnO/ZnS via Kirkendall effect using ZnO nanorods (NRs). The morphologies, optical properties, compositions, and crystal structures of the as synthesized materials are systematically studied using UV–vis, PXRD, FESEM, TEM, EDS, XPS, etc. The process of synthesis and growth mechanism of hollow NRs is suggested based on the Kirkendall effect. A hollow nanomaterial, envisaged being highly efficient for molecule adsorption on its surface, the as synthesized materials were used for the photocatalytic degradation of methylene blue (MB) dye. MB degradation efficiency of 96% within 60 min was performed over ZnO/ZnS hollow NRs, which was 2.6-fold greater than that of ZnO. The rate constant of ZnO/ZnS heterostructure was 0.045 min−1, which was 5.5 times larger than that of bare ZnO. We have concluded our work in the directions towards the synthesis of various semiconductor hollow nanostructures for the varied catalytic reactionsItem CO2 to Cyclic Carbonate: A Mechanistic Insight of a Benign Route Using Zinc(II) Salophen Complexes(Wiley, 2023-12) Ray, SaumiZinc(II) Schiff base complexes with different substituents at 5, 5’ positions have been synthesized to study the effect of the electronic environment of the metal towards the cycloaddition reaction between CO2 and epoxide. The complexes have been characterized by FT-IR, XPS, NMR, electronic spectroscopy, LC–MS, and TGA. We have used density functional theory to study the electronic structure of the Zn(II) complexes and modelled the electronic spectra and the mechanism of catalysis. Results obtained from DFT and LC–MS indicate the dimeric structures for all the complexes except ZnL4. The monomeric ZnL4 has the strongest electron withdrawing group, i. e., −NO2 at 5, 5’ positions along with two labile water molecules attached to the Zn center. The dimeric complexes exhibit good to moderate yield for cycloaddition reaction to styrene carbonate under solvent-free conditions and a relatively low reaction temperature of 80 °C, with CO2 pressure of ~1 atm. The best yield has been achieved by ZnL4. Different rate-determining steps are captured by the DFT studies for dimeric and monomeric complexes. Without taking any preventing measure of dimerization by attaching the bulky tBu groups, relatively lesser catalytic amounts of all the complexes have shown yields of cyclic carbonate between 53–74 %, depending on the nature of the substituent present.Item Regiodivergent Synthesis of Cinnoline-Fused Indazolones through Pd-Catalyzed Annulation of 1-Arylindazolones with Allenoates(ACS, 2022-01) Sakhuja, RajeevA tender-hearted Pd(II)-catalyzed C–H activation of 1-arylindazolones followed by an oxidative [4 + 2] annulation reaction has been accomplished, engaging allenoates as annulating partners. Using this strategy, two different regioisomeric forms of cinnoline-fused indazolones possessing internal and exocyclic double bonds were synthesized in acetic acid and dioxane, respectively. Mild and aerobic conditions, avoiding the use of any metal–oxidant, highlights the rewards of this oxidative annulation protocol.