Department of Chemistry
Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1924
Browse
305 results
Search Results
Item Photocatalyst-free regioselective sulfonamidation of N-(2-hydroxyaryl)amides in visible-light(RSC, 2024-09) Grover, NitikaIn this work, we report a regioselective sulfonamidation of N-(2-hydroxyaryl)amides with iminoiodinanes and iodine in visible light at room temperature. The method does not require a strong oxidant, metal or photocatalyst and enables direct functionalization of a C–H bond to a C–N bond. Mechanistic investigations suggest in situ generation of an N-centered radical from N,N-diiodo-sulfonamide by homolytic N–I bond cleavage followed by its site-specific addition to N-(2-hydroxyaryl)amides to furnish para-sulfonamide derivatives.Item Investigation of aluminum-based plasmonic devices for sensing applications in the near-infrared region(SPIE, 2024-03) Arora, Pankaj; Grover, NitikaWe present surface plasmon resonance-based sensing devices with Aluminum (Al) as the plasmonic metal in the near-infrared region and analyze the output performances in terms of higher sensitivity and the Figure of Merit (FOM). The optical characteristics of Al-based plasmonic sensors are explored using different interrogation modes (angle and wavelength). Biorecognition elements help to enhance the sensor’s performance, for which 2D nanomaterials are explored for the biofunctionalization of the top surface. In the end, we also present an Al-based plasmonic device that utilizes both prism and nanostructure-based configurations, and the same designed parameters for the device offer high sensitivity and FOM in both angle and wavelength interrogation.Item Iodine(III)-induced cascade annulation of β-cyanoporphyrins for the efficient synthesis of n-aryliminonaphtho-fused and n-aryl-carboxamide porphyrins(Wiley, 2025-12) Grover, Nitika; Kumar, DalipMeso-β fused porphyrins with tunable optoelectronic properties are attractive candidates for applications in light-harvesting, sensing, and catalysis, yet their synthesis often requires harsh conditions or tedious synthetic routes. Herein, a mild, operationally simple, and Cu(OTf)2-catalyzed protocol is reported to access meso-N-aryliminonaphtho-fused and N-arylcarboxamide porphyrins from readily available β-cyanoporphyrins and diaryliodonium salts. Reaction selectivity is controlled by the water content present in the reaction mixture, affording either fused imines or carboxamides in high yields. The protocol tolerates different symmetrical diaryliodonium salts and enables the preparation of free-base, Zn (II), and Cu (II) porphyrin derivatives, all fully characterized by NMR, UV–visible spectroscopy, high resolution mass spectrometry, electrochemistry, and single crystal X-ray diffraction. The π-extended systems exhibit distinct bathochromic shifts (≈42 nm in Soret and ≈80–90 nm in Q-bands) and narrowed highest molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps up to 1.54 eV. Electrochemical studies reveal that fused porphyrins exhibited anodically shifted reduction potentials, while Density functional theory calculations attribute the gap reduction to LUMO stabilization and HOMO destabilization induced by fusion. Overall, this strategy provides rapid access to structurally diverse π-extended porphyrins with tailored photophysical and redox properties.Item I(III)-promoted facile and rapid synthesis of imidazo-azepino-fused porphyrins with enhanced absorption as singlet oxygen generators(Wiley, 2026-01) Grover, NitikaA facile, high-yielding synthetic protocol has been developed to access azepino-fused porphyrins via iodine(III)-mediated oxidative intramolecular cyclization of β-imidazole or benzimidazole substituted porphyrins. The absorption of the synthesized compounds showed the characteristic features of meso-β-fused porphyrins, with intense Soret bands centered between 440 and 460 nm and two weak bands ranging from 550 to 750 nm (Q-bands) Among the synthesized compounds, the free-base imidazo-azepino-fused porphyrin was found to be an efficient 1O2 producer with a higher singlet oxygen quantum yield (ΦΔ ∼0.78 in DMF) as compared to H2TPP (ΦΔ = 0.64 in DMF). It was observed that the protonated form of 4aH2 exhibits a significant red shift of ∼24 nm in Soret and ∼150 nm in Q-bands. Fitting of the titration data of 4aH2 with TFA yielded an apparent pKa of ∼3.58, demonstrating that imidazole fusion enhances the basicity of the porphyrin system.Item Emerging devices and materials(Springer, 2026-01) Grover, NitikaThis chapter surveys the fast-moving landscape of emerging devices and materials that are reshaping electronics, photonics, energy, and biomedicine. We begin with the motivations beyond silicon limits and outline advances in flexible and wearable platforms—displays, skin-like sensors, and body-conformal systems—that enable continuous health and environment monitoring. We then profile quantum materials (topological insulators, 2D semiconductors, and quantum dots) alongside next-generation energy technologies, including solid-state batteries, supercapacitors, and perovskite solar cells, highlighting the performance gains and stability/sustainability challenges that steer current research. At the device level, we discuss advanced semiconductors (GaN power devices, silicon photonics, and organic semiconductors) that deliver higher speed, power density, and integration. Bridging biology and electronics, we review biocompatible implants, self-healing materials, and biohybrid systems that promise personalized therapies and regenerative interfaces. Finally, we examine nanotechnology-driven catalysts and medicines, as well as smart and sustainable materials (piezoelectrics, metamaterials, biodegradable polymers) that enable self-powered sensing, wave engineering, and circular-economy pathways. Across these domains, the chapter emphasizes cross-disciplinary design, scalable fabrication, low-toxicity alternatives, and life-cycle thinking as the keys to translating laboratory breakthroughs into human-centered, eco-conscious systems.Item Nanotechnology in electronic devices(Springer, 2026-01) Grover, NitikaThis chapter synthesizes how nanoscale phenomena—quantum tunneling and confinement, large surface-to-volume ratios, ballistic transport, anisotropic carrier motion in low-symmetry 2D materials, and plasmonics—reshape device physics and enable new electronic–photonic functionalities. It surveys key nanomaterials—graphene/CNTs, quantum dots, TMDs, and metal-oxide nanostructures—and their roles in flexible/wearable platforms, nanosensors, energy systems, and optoelectronics. The chapter then reviews fabrication toolkits spanning top-down lithographies and bottom-up growth (CVD/ALD) that underpin modern nano-integration, followed by device-level advances from FinFETs to gate-all-around FETs that extend electrostatic control past planar scaling. It highlights nanotechnology’s contributions to quantum computing—materials, structures, and coherence considerations for scalable qubits—before assessing energy-efficient nanoelectronics, including low-power memories and architectures, alongside energy harvesting and storage themes. Finally, it connects these threads to optoelectronic devices (e.g., high-bandwidth graphene/TMD photodetectors) and concludes with challenges in stability, manufacturability, and reliable control at atomic dimensions that will steer the next wave of nanoelectronic technologies.Item Meso-substitution controlled synthesis of bodipy–dpm conjugates: a pathway to tailored photophysical properties(2026) Roy, Aniruddha; Arora, Pankaj; Grover, NitikaWe show that the electronic nature of the meso-aryl substituent in 1,3,5,7-tetramethyl BODIPYs governs the reactivity of the 1,7-methyl (α-methyl) groups toward the Knoevenagel condensation. Reaction of pyrrole-2-aldehyde with electron-deficient 1,3,5,7-tetramethyl-meso-pentafluorophenyl and 1,3,5,7-tetramethyl-meso-4-nitrophenyl BODIPYs yields double condensation at the 1,7-methyl positions to give the corresponding bis(pyrrole) derivatives, whereas the electron-rich meso-tolyl analogue selectively undergoes single condensation at only one of the α-methyl groups under identical conditions. This substituent-dependent divergence extends to reactions with 1,9-diformyl-meso-aryl dipyrromethanes, enabling access to structurally distinct BODIPY–DPM conjugates. Reaction of 1,9-diformyl-DPM with meso-tolyl BODIPY selectively yields acyclic monosubstituted BODIPY–DPM conjugates, whereas the higher reactivity of meso-pentafluorophenyl BODIPY enables condensation between both 1,7-methyl groups and the two aldehyde functionalities of the diformyl-DPM scaffold, affording cyclic, porphyrin-like BODIPY–DPM frameworks. Notably, meso-pentafluorophenyl BODIPYs also undergo nucleophilic aromatic substitution of the para-fluorine atom by piperidine under the condensation conditions, as confirmed unambiguously by single-crystal X-ray diffraction. The resulting BODIPY–DPM and BODIPY–pyrrole conjugates exhibit pronounced bathochromic shifts (90–180 nm relative to parent BODIPYs), deep-red to near-infrared absorption (~670 nm) and emission (~750 nm), enlarged Stokes shifts, and strong intramolecular charge-transfer character. These features translate into efficient heavy-atom-free triplet formation, with singlet-oxygen quantum yields reaching up to 0.45. A representative conjugate (10) exhibits potent photodynamic activity in B16F10 melanoma cells with minimal dark toxicity (IC₅₀ = 0.95 μM). TD-DFT analysis indicates that excited-state twisting reduces ΔEST, thereby facilitating heavy-atom-independent intersystem crossing. Collectively, these results establish a robust molecular design framework for next-generation heavy-atom-free photosensitizers.Item A large step down buck converter for small scale hydrogen generation(IEEE, 2025-12) Pande, Surojit; Kumar, RajneeshThis paper presents a large step-down buck converter topology employing a coupled inductor and a singles-witch configuration to achieve efficient step-down voltage conversion with an extended conversion ratio. The proposed architecture mitigates the limitations of conventional buck converters by leveraging a coupled inductor to enhance voltage gain while maintaining a moderate duty cycle, thereby reducing conduction and switching losses. The developed single-switch topology is validated using MATLAB Simulation and comprehensive theoretical analysis is conducted, including steady-state operation, voltage gain expression, and component stress evaluation representing hydrogen electrolyser as resistive load in steady stateItem Doped nickel-based nanocatalysts for electrochemical water splitting: a review(ACS, 2025-10) Pande, SurojitThe growing demand for clean energy solutions to address fossil fuel depletion and global warming has increased the pace for the search for sustainable alternatives. To address this situation, hydrogen energy is emerging as a promising method due to its zero pollution and high energy density. Electrocatalytic water splitting is a promising technology for large-scale hydrogen production. Generally, electrocatalysts work well for either the HER or the OER, but not both. Developing catalysts that can be efficiently used for overall water splitting is necessary for commercial viability. Nickel-based materials, specifically when doped with metals (e.g., Fe, Co, W, Cu, Ru, and Ir) and nonmetals (e.g., C, F, and P), have shown great potential because of their versatile chemical properties, corrosion resistance, and structural stability. This review provides a comprehensive overview of recent advancements in doped nickel-based electrocatalysts, which focuses on nickel oxides, chalcogenides, phosphides, nitrides, and single-atom catalysts (SACs). It discusses fundamental mechanisms of HER and OER, strategies for enhancing electrocatalytic performance through doping, defect engineering, and electronic structure modulation. It also discusses the effect of nonmetal and metal doping on activity and stability. The review also emphasizes the importance of systematic experimental approaches like doping ratios, accurate surface area corrections, and operando methods to better understand the relationship between electronic structure and electrocatalytic performance. It also highlights the research gaps and the future directions that aim to advance the design of efficient, stable, and cost-effective nickel-based electrocatalysts, which can contribute to the development of sustainable hydrogen energy production.Item Evaluating LLMs for zeolite synthesis event extraction (ZSEE) : a systematic analysis of prompting strategies(2025-12) Ray, SaumiExtracting structured information from zeolite synthesis experimental procedures is critical for materials discovery, yet existing methods have not systematically evaluated Large Language Models (LLMs) for this domain-specific task. This work addresses a fundamental question: what is the efficacy of different prompting strategies when applying LLMs to scientific information extraction? We focus on four key subtasks: event type classification (identifying synthesis steps), trigger text identification (locating event mentions), argument role extraction (recognizing parameter types), and argument text extraction (extracting parameter values). We evaluate four prompting strategies - zero-shot, few-shot, event-specific, and reflection-based - across six state-of-the-art LLMs (Gemma-3-12b-it, GPT-5-mini, O4-mini, Claude-Haiku-3.5, DeepSeek reasoning and non-reasoning) using the ZSEE dataset of 1,530 annotated sentences. Results demonstrate strong performance on event type classification (80-90\% F1) but modest performance on fine-grained extraction tasks, particularly argument role and argument text extraction (50-65\% F1). GPT-5-mini exhibits extreme prompt sensitivity with 11-79\% F1 variation. Notably, advanced prompting strategies provide minimal improvements over zero-shot approaches, revealing fundamental architectural limitations. Error analysis identifies systematic hallucination, over-generalization, and inability to capture synthesis-specific nuances. Our findings demonstrate that while LLMs achieve high-level understanding, precise extraction of experimental parameters requires domain-adapted models, providing quantitative benchmarks for scientific information extraction.