http://nopr.niscpr.res.in/handle/123456789/67173 2026-10-13T03:22:10Z http://nopr.niscpr.res.in/handle/123456789/68273 Title: Theoretical investigation and prediction of 13C and 1H nuclear magnetic resonance chemical shifts in aromatic and new organometallic sandwich systems Authors: Fenzlaff, Marc; Christoph Potzel, Oliver Abstract: This study evaluates a density functional theory (DFT)-based workflow for the prediction of 13C and 1H nuclear magnetic resonance (NMR) chemical shifts in aromatic and organometallic systems. Aromatic reference compounds, namely benzene, toluene, nitrobenzene, aniline and phenol, have been investigated at the B3LYP/TZVP level of theory using the Gauge-Including Atomic Orbital (GIAO) method and implicit chloroform solvation. The calculated chemical shifts show strong agreement with experimental reference data, with coefficients of determination above 0.98. Linear regression-based scaling has further reduced systematic deviations. To assess the transferability of the computational protocol to metal-containing systems, three additional organometallic benchmark compounds with published experimental 13C and 1H NMR data have been investigated: ferrocene, acetylferrocene and lithium cyclopentadienide. These compounds represent complementary organometallic bonding motifs, including sandwich complexes, a substituted ferrocene derivative with chemically distinct carbon and proton environments, and a lithium-containing cyclopentadienyl system. The workflow has been subsequently applied to pentaisopropylcyclopentadienyl-lithium (CpiPr5Li (A)), pentaisopropylcyclopentadienylaluminium (CpiPr5Al (B)), and a lithium-aluminium heterobimetallic dimetallocene (CpiPr5Al–LiCpiPr5 (C)). For these target systems, calculated 13C and 1H chemical shifts have been evaluated by cross-platform comparison using Gaussian 09 and ORCA 6.0.1. Gaussian and ORCA have yielded closely matching predictions for the carbon and proton chemical shifts of compounds A and B, supporting the numerical reproducibility of the computational workflow. A comparison between the TZVP and QZVP basis sets has shown that QZVP substantially increased computational cost without improving predictive accuracy for the investigated aromatic reference systems. Overall, the results support B3LYP/TZVP/GIAO as an efficient computational protocol for the prediction and interpretation of 13C and 1H NMR chemical shifts in structurally diverse organic and organometallic systems. Page(s): 643-656 2026-07-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/68272 Title: Isolation, structural characterization, and in silico evaluation (ADMET, PASS, and molecular docking) of a novel flavonol-di-O-xyloside from mango honey Authors: Yadav, Akanksha; Shankar Singh, Sudhir; De, Tanmoy; Maitra, Sangita; Sharma, Aparna; Pratap Singh, Ranvijay; Bala, Shashi Abstract: The present research work incorporates isolation and structure elucidation of a new compound 3,4’-dihydroxyflavonol- 5,8-di-O-β-D-Xyloside (E), from mango honey. The compound has been separated on silica column chromatography and further purified by preparative HPLC instrument containing column; Gemini (250×4.6 mm, 5 μ) with mobile phase (A = 20 mM ammonium bicarbonate in water, B = acetonitrile). The compound has been subjected to ADMET analysis and the results indicate that the compound can penetrate the CNS with permeability value 0.33 while Caco-2 cell permeability is favourable (–6.88 log cm/s) which demonstrates that the compound has drug-like characteristics. The docking study of compound has also been performed using the peroxisome proliferator-activated receptor gamma (PPARγ) protein as the target and the results show that compound 3,4’-dihydroxyflavonol-5,8-di-O-β-D-Xyloside (E) may act as a PPARγ agonist and could potentially find use in the treatment of diabetic dyslipidemia and non-alcoholic fatty liver disease (NAFLD). Page(s): 657-662 2026-07-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/68271 Title: Methylene resonance and conjugation effects in 3-(4-bromophenyl)-5- (substituted phenyl)-4,5-dihydroisoxazoles: Synthesis, spectral QSAR studies, in silico and in vitro activities evaluation Authors: Sudha, P; Balasundari, S; Devika, K; Muthuvel, I; Thirunarayanan, G Abstract: In this study we report the synthesis and biological evaluation of series of 3-(4-bromophenyl)-5-substituted phenyl-4,5- dihydroisoxazoles (1-8). These 3-(4-bromophenyl)-5-substituted phenyl-4,5-dihydroisoxazoles have been successfully synthesised from 4-bromophenyl chalcone derivatives with hydroxylamine hydrochloride by condensation cum cyclisation method, and their structures are confirmed by FT-IR, 1H, and 13C NMR spectroscopy techniques. The characteristic spectral frequencies and chemical shifts of these isoxazolines have been correlated with Hammett substituent constants and F, R parameters by QSAR analysis. The antimicrobial activity of synthesised isoxazolines (1-8) have been assessed in vitro against two Gram-positive and two Gram-negative bacterial strains, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Klebsiella pneumonia and two fungal strains Candida aureus, Candida albicans by Kirby-Bauer disc diffusion method. The molecular structure of 3-(4-bromophenyl)-5-substituted phenyl-4,5-dihydroisoxazoles has been explored using Density Functional Theory (DFT) at the B3LYP/6-311G(d,p) level of theory. The simulations yield information about total energy, frontier molecular orbitals (HOMO and LUMO), and molecular electrostatic potential (MEP) surfaces. Molecular docking investigation of 3-(4-bromophenyl)-5-substituted phenyl-4,5-dihydroisoxazoles (1–8) against the bacterial protein DNA gyrace (PDB ID: 4URO) reveals that compound 8 has the highest binding affinity value (– 6.68 kcal/mol). The findings of the ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) study help the ongoing development of pharmacologically active medicines. Page(s): 663-679 2026-07-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/68270 Title: Chelating molecular imaging probe amino polycarboxylic acid-manganese (II) complexes: As potent photoluminescent materials for imaging Authors: Selvi M, Amutha; J, Sivasankari; Vinoliya E, Merlin; B, Nandini Abstract: The most used gadolinium and manganese-based contrast agents improve the visibility of internal cell body structures in MRI. To overcome the nephrogenic systemic fibrosis (NSF) related to renal impairment, we are in the race to find safer MRI contrast agents. The utilization of some paramagnetic transition metal ions, Mn2+ and Fe3+ that may effectively relax the water protons is a potential strategy for developing substitute contrast agents for Gd3+chelates and these metals are less harmful than Gd3+. This investigation concentrates on synthesis of DTPA and EDTA-based manganese complexes with two different poly amino carboxylic acids to enhance as potential contrast agents with further studies. DTPA/EDTA anhydrides and respective amino substituted ligands have been prepared under nitrogen atmosphere and complexes have been prepared by reflux method at pH 8.4 using 1N NaHCO3 solution which has been characterized by UV-Vis, FTIR, 1H NMR, EPR, and TGA studies. FT-IR analysis shows 510 cm–1 M-O bond and shifting of the ranges observed on comparing ligand and metal studies which confirms the metal complex formation. 10.5 – 10.6 ppm for COOH group and 5.8 – 5.9 ppm for N-H group confirm the formation of poly amino carboxylic acid ligands with DTPA/EDTA. Nuclear spin I=5/2 reveals the 3d5 electronic configuration for Mn. The Mn complexes have shown good thermal stability, and EDTA complexes have good bacterial-resistant activity. Both DTPA/EDTA complexes have good fluorescence activities. The manganese-based complexes show good resistance against both Gram positive and Gram negative bacteria which are well-suited to the human body, with excellent emissions of complexes that may lead to further studies for imaging agents. Page(s): 680-690 2026-07-01T00:00:00Z