http://dspace.bits-pilani.ac.in:8080/jspui/handle/123456789/1924 2026-04-01T13:44:11Z http://dspace.bits-pilani.ac.in:8080/jspui/handle/123456789/20632 Title: Photocatalyst-free regioselective sulfonamidation of N-(2-hydroxyaryl)amides in visible-light Authors: Grover, Nitika Abstract: In 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. 2024-09-01T00:00:00Z http://dspace.bits-pilani.ac.in:8080/jspui/handle/123456789/20629 Title: Investigation of aluminum-based plasmonic devices for sensing applications in the near-infrared region Authors: Arora, Pankaj; Grover, Nitika Abstract: We 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. 2024-03-01T00:00:00Z http://dspace.bits-pilani.ac.in:8080/jspui/handle/123456789/20625 Title: Iodine(III)-induced cascade annulation of β-cyanoporphyrins for the efficient synthesis of n-aryliminonaphtho-fused and n-aryl-carboxamide porphyrins Authors: Grover, Nitika; Kumar, Dalip Abstract: Meso-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. 2025-12-01T00:00:00Z http://dspace.bits-pilani.ac.in:8080/jspui/handle/123456789/20624 Title: I(III)-promoted facile and rapid synthesis of imidazo-azepino-fused porphyrins with enhanced absorption as singlet oxygen generators Authors: Grover, Nitika Abstract: A 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. 2026-01-01T00:00:00Z