Publications

Untreated and alkali-treated (5% NaOH) Chloris barbata flower fibers (CBFFs) were used to fabricate the composites by hand lay-up method. Novel composite plates were manufactured by changing fiber weight fraction (5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, and 25 wt.%), raw and 5% NaOH treated fibers. The impact of NaOH treatment and fiber weight fraction on tensile, flexural, impact, morphological, and thermal properties of CBFF reinforced epoxy composites were examined and reported for the first time in this article. The tensile, flexural, and impact properties of the composites were increased up to 20 wt. % fiber additions and after that dropped. After the tensile testing, broken cross-sections of the composites were analyzed by scanning electron microscopy (SEM), which showed that NaOH treated CBFF reinforced composite has better interfacial bonding and lesser voids. Thermogravimetric analysis (TGA), Fourier transform infrared analysis (FTIR), and Atomic force microscope (AFM) analysis of composites also pointed out that alkali-treated CBFF is a suitable material for reinforcement with the epoxy polymer matrix.

Polymeric bio-composites synthesized <i>via</i> a green approach using natural herbs have fascinating anticoagulant activity due to their eco-friendly and non-toxic behavior towards various physical and chemical actions. Herein, we introduce a simple and eco-friendly approach for the fabrication of a new hybrid type of bio-composite based on sulfated carboxymethyl cellulose (S-CMC) and <i>Azadirachta indica</i> leaf powder (S-CMC/NLP). First, a non-toxic sulfating agent called N(SO₃Na)₃ was used to modify carboxymethyl cellulose into S-CMC. With an ion exchange capacity of 0.25 meq. g^-1, the level of sulfation (%) of S-CMC (modified polysaccharide) was measured to be 12.01%. Three types of S-CMC/NLP bio-composites were developed by varying the concentration of NLP. FE-SEM, EDX, and XRD were used to characterize the structural features of S-CMC/NLP bio-composites. FTIR spectroscopy indicated that the S-CMC/NLP bio-composite possesses COO^-, -OH and SO^3- groups, suggesting the structural similarity to heparin. In addition, the anticoagulant effect of the S-CMC/NLP bio-composite was investigated using PT and APTT assays. The APTT investigation confirmed that following the intrinsic pathway of the coagulation system, 2-NLP/S-CMC bio-composite dose-dependently (0.045-0.28 mg mL^-1) prolonged the time of blood coagulation compared to control (pure plasma). The S-CMC/NLP bio-composite showed its potential as a new, safe, and effective candidate for anticoagulant activity.

A novel gold-catalyzed cycloisomerization of 1,6-diynes was achieved, providing an atom-economic approach to a diverse set of bicyclo[2.2.1]hept-5-en-2-ones in moderate to good yields. With unsymmetrical starting materials with two different internal alkynyl substituents, to some extent, the regioselectivity could be controlled by both electronic and steric factors. This unprecedented reactivity pattern may inspire new and unconventional strategies for the preparation of bridged ring systems.

In this work, we report a facile synthesis of uniform SnO2@C yolk-shell nanospheres as high-performance anode materials for lithium ion batteries (LIBs). The yolk-shell structured SnO2@C nanospheres were fabricated through a two-step sol-gel coating process by using tetraethyl orthosilicate (TEOS) and resorcinol-formaldehyde (RF) as precursors, where the silica interlayer not only acts as a template to produce the void space, but also promotes the coating of the RF layer. The synthesis is easy to operate and allows tailoring the carbon shell thickness and void space size. The resultant SnO2@C yolk-shell nanospheres possess a hollow highly crystalline SnO2 core (280-380 nm), tailored carbon shell thickness (15-25 nm) and a large void space size (100-160 nm), a high surface area (∼205 m(2) g(-1)), a large pore volume (∼0.25 cm(3) g(-1)), as well as a high SnO2 content (77 wt%). When evaluated as an anode of LIBs, the materials manifest superior electrochemical performance with a high lithium storage capability (2190 mA h g(-1) in initial discharge capacity; >950 mA h g(-1) in the first 10 cycles), a good cycling performance and an excellent rate capability.

Abstract The current article is based on the synthesis of new N ‐ and O‐ alkylated sulfonamides; 4‐{[Ethyl‐(naphthalene‐2‐sulfonyl)‐amino]‐methyl}‐cyclohexanecarboxylic acid ethyl ester ( IV ), 4‐[(2‐nitrobenzene‐1‐sulfonylamino)‐methyl]‐cyclohexanecarboxylic acid ethyl ester ( V ) and 4‐[(Cyclohexa‐1,5‐dienesulfonylamino)‐methyl]‐cyclohexanecarboxylic acid methyl ester ( VI ). These compounds were characterized by FT‐IR spectroscopy, ESI‐MS spectrometry, and X ‐ray crystallography. Density functional theory (DFT) of sulfonamide esters was carried out through the Gaussian‐09 program to optimize structures. Hirshfeld surface analysis has been performed to understand the intermolecular interactions. Biological evaluation of all compounds was done to check their application for antibacterial ( Halomonas halophila, Shigella sonnei, Bacillus subtilis, Chromohalobacter salexigens, Staphylococcus aureus Escherichia coli, Serratia marcescens, Chromohalobacter israelensis, Nesseria gonorrhoeae , Klebsiella pneumonia , and Halomonas salina) , anti‐fungal ( Aspergillus niger ), enzyme inhibition activity (Acetylcholine esterase and butyrylcholine esterase) and anti‐oxidant activity (DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) scavenging method, were carried out. Molecular docking was performed to check the interaction modes of these sulfonamide esters.