Bhijan Neupane

Sulfonamide derivatives are structurally versatile compounds with relevance to molecular electronics, spectroscopy, and medicinal chemistry. In this study, a cheminformatics-guided physicochemical assessment of 3-bromo-N-tert-butylbenzene-1-sulfonamide (BTBS) was performed by integrating density functional theory, electronic-structure analysis, nonlinear optical descriptors, and preliminary in silico bioactivity assessment. Geometry optimization revealed a rigid sulfonyl framework with a planar aromatic core, while the tert-butyl substituent imposed a non-coplanar sulfonamide orientation that modulates conjugation and charge distribution. Infrared and Raman vibrational assignments reproduced characteristic sulfonamide modes, supporting the proposed bonding framework. The large frontier-orbital energy gap is consistent with high kinetic stability and low intrinsic reactivity, with solvent-dependent stabilization described more effectively by conductor-like continuum models. Electronic-structure and density-of-states analyses revealed functional separation between the aromatic backbone, the electron-withdrawing sulfonamide-bromine unit, and the weakly donating tert-butyl group, indicating intramolecular charge transfer without a classical push-pull architecture. Time-dependent calculations predicted dominant π-[Formula: see text] transitions with solvent-induced red shifts and enhanced oscillator strengths. The calculated first-order hyperpolarizability was higher than the urea reference value, suggesting a molecular-level second-order nonlinear optical response driven by electronic asymmetry. Local reactivity descriptors identified the sulfonamide heteroatoms and brominated ring as the principal reactive regions. Similarity-based read-across and molecular docking provided preliminary computational evidence for possible biological interactions. Overall, BTBS is proposed as a candidate scaffold for follow-up experimental validation at the interface of electronic-material chemistry and medicinal chemoinformatics.

Plant-mediated synthesis offers a low-toxicity route for preparing zinc oxide-based structures; however, the extent of ZnO formation depends strongly on precursor chemistry, phytochemical composition, and post-synthesis heat treatment. In this study, a stem-rich aqueous extract of Buddleja paniculata was used to precipitate a zinc-based precursor from ZnSO4·7H2O under alkaline conditions. The oven-dried precursor was coded as GB-Sample, and portions were calcined at 350 °C for 1 h and 450 °C for 2 h to produce GB-ZnO-350 and GB-ZnO-450, respectively. The materials were examined by XRD, FT-IR, and FESEM-EDX to track calcination-driven phase evolution, bonding changes, and morphology development. The XRD patterns show a progressive transition from a poorly ordered precursor to more ZnO-like calcined products, with GB-ZnO-450 exhibiting the strongest ZnO-related reflections, whereas GB-ZnO-350 already demonstrates credible ZnO-rich development under milder conditions. FT-IR spectra show suppression of precursor-associated hydroxylated/organic bands after calcination together with the emergence of Zn-O-region vibrations, although residual sulfate- and carbon-containing species remain. The FESEM images of GB-ZnO-350 reveal compact micrometre-scale secondary agglomerates assembled from anisotropic rod-/plate-like subunits, and image analysis gives a broad apparent diameter distribution of approximately 90-400 nm. Spot EDX shows Zn and O as the dominant elements with minor S and C, consistent with a ZnO-rich calcined product. The study demonstrates a coherent precursor-to-calcined transformation and shows that 350 °C for 1 h is sufficient to obtain a scientifically credible ZnO-rich material, whereas 450 °C for 2 h produces the more ZnO-like product under the present processing route.

The structural and electronic properties of the title molecule were investigated using Density Functional Theory (DFT) at the B3LYP/6-311G++(d,p) level in Gaussian G09 W and GaussView. Geometrical optimization was performed to determine the most stable configuration, with total energy computations revealing the minimized energy state. The electronic properties were analyzed through HOMO-LUMO gap calculations, yielding a band gap of 8.68708 eV, indicating high kinetic stability and low reactivity. Global reactivity indices, including electrophilicity, hardness, and electronegativity, were evaluated to ascertain the chemical behavior of the molecule. Molecular Electrostatic Potential (MEP) analysis identified reactive sites, with oxygen atoms showing a negative potential for electrophilic attack, while hydrogen atoms exhibited a positive potential, favoring nucleophilic interactions. Frontier molecular orbitals were further explored using the Total, Partial, and Overlap Density of States (TDOS, PDOS, and OPDOS) to elucidate the charge distribution and orbital contributions. Electron Localization Function (ELF) and Localized Orbital Locator (LOL) analyses revealed the electron density distribution, highlighting regions of strong covalent interactions and localized bonding characteristics. A Reduced Density Gradient (RDG) was employed to visualize non-covalent interactions, indicating van der Waals interactions and steric effects. Fukui functions and dual descriptors were calculated to predict reactive sites and charge-transfer tendencies. Spectroscopic characterization via FT-IR and FT-Raman spectroscopy confirmed the key functional group vibrations. These insights contribute to the understanding of the reactivity and stability of the title molecule and its potential applications in materials science and biochemistry.